Now,lodging is a major constraint factor contributing to yield loss of maize (Zea mays L.) under high planting density.Chemical regulation and nitrogen fertilizer could effectively coordinate the relationship between ...Now,lodging is a major constraint factor contributing to yield loss of maize (Zea mays L.) under high planting density.Chemical regulation and nitrogen fertilizer could effectively coordinate the relationship between stem lodging and maize yield,which significantly reduce lodging and improve the grain yield.The purpose of this study was to explore the effects of chemical regulation and different nitrogen application rates on lodging characteristics,grain filling and yield of maize under high density.For this,we established a field study during 2017 and 2018 growing seasons,with three nitrogen levels of N100 (100 kg ha^(–1)),N200 (200 kg ha^(–1)) and N300 (300 kg ha^(–1)) at high planting density (90 000 plants ha^(–1)),and applied plant growth regulator (Yuhuangjin,the mixture of 3% DTA-6 and 27% ethephon) at the 7th leaf.The results showed that chemical control increased the activities of phenylalanine ammonia-lyase (PAL),tyrosine ammonia-lyase (TAL),4-coumarate:Co A ligase (4CL),and cinnamyl alcohol dehydrogenase (CAD),and increased the lignin,cellulose and hemicellulose contents at the bottom of the 3rd internode,which significantly reduced the lodging percentage.The lignin-related enzyme activities,lignin,cellulose and hemicellulose contents decreased with the increase of nitrogen fertilizer,which significantly increased the lodging percentage.The 200 kg ha^(–1) nitrogen application and chemical control increased the number,diameter,angle,volume,and dry weight of brace roots.The 200 kg ha^(–1) nitrogen application and chemical control significantly increased the activities of ADP-glucose pyrophosphorylase (AGPase),soluble starch synthase (SSS) and starch branching enzyme(SBE),which promoted the starch accumulation in grains.Additional,improved the maximum grain filling rate (V_(max)) and mean grain filling rate (V_(m)),which promoted the grain filling process,significantly increased grain weight and grain number per ear,thus increased the final yield.展开更多
Grain water relations play an important role in grain filling in maize. The study aimed to gain a clear understanding of the changes in grain dry weight and water relations in maize grains by using hybrids with contra...Grain water relations play an important role in grain filling in maize. The study aimed to gain a clear understanding of the changes in grain dry weight and water relations in maize grains by using hybrids with contrasting nitrogen efficiencies under differing nitrogen levels. The objectives were: 1) to understand the changes in dry matter and percent moisture content(MC) during grain development in response to different nitrogen application rates and 2) to determine whether nitrogen application affects grain filling by regulating grain water relations. Two maize hybrids, high N-efficient Zhenghong 311(ZH311) and low N-efficient Xianyu 508(XY508), were grown in the field under four levels of N fertilizer: 0, 150, 300, and 450 kg N ha;during three growing seasons. Dry weight, percent MC and water content(WC) of basal-middle and apical grains were investigated. The difference in the maximum WC and filling duration of basal-middle and apical grains in maize ears resulted in a significant difference in final grain weight. Grain position markedly influenced grain drying down;specifically, the drying down rate of apical grains was faster than that of basal-middle grains. Genotype and grain position both influenced the impact of nitrogen application rate on grain filling and drying down. Nitrogen rate determined the maximum grain WC and percent MC loss rate in the middle and the late grain-filling stages, thus affecting final grain weight. The use of high N-efficient hybrids, combined with the reduction of nitrogen application rate, can coordinate basal-middle and apical grain drying down to ensure yield. This management strategy could lead to a win-win situation in which the maximum maize yield, efficient mechanical harvest and environmental safety are all achieved.展开更多
The environmental temperature occurring during the grain filling stage is an important factoraffecting starch synthesis and accumulation in rice. We investigated starch accumulation, amylaseactivity and starch granule...The environmental temperature occurring during the grain filling stage is an important factoraffecting starch synthesis and accumulation in rice. We investigated starch accumulation, amylaseactivity and starch granule size distribution in two low-amylose japonica rice varieties, Nanjing 9108 andFujing 1606, grown in the field at different filling temperatures by manipulating sowing date. The two ricevarieties exhibited similar performances between two sowing dates. Total starch, amylose andamylopectin contents were lower at the early-filling stage of T1 treatment (Early-sowing) compared withthose at the same stage in T2 treatment (Late-sowing). In contrast, at the late-filling stage, when fieldtemperatures were generally decreasing, total starch and amylopectin contents in T1 were highercompared to those in T2. The ideal temperature for strong activity of ADP-glucose pyrophosphorylaseand soluble starch synthase was about 22℃. A higher temperature from the heading to maturity stagesin T1 increased the activities of starch branching enzyme and suppressed the activities of granule boundstarch synthetase and starch debranching enzyme. We found that rice produced larger-sized starchgranules under the T1 treatment. These results suggested that due to the early-sowing date, the hightemperature (30℃) occurring at the early-filling stage hindered starch synthesis and accumulation,however, the lower temperatures (22 ℃) at the late-filling stage allowed starch synthesis and accumulationto return to normal levels.展开更多
The grain filling of inferior spikelets is much less complete than that of superior spikelets in rice cultivars with large panicles and numerous spikelets and is promoted by moderate soil drying(MD)post-anthesis.A gro...The grain filling of inferior spikelets is much less complete than that of superior spikelets in rice cultivars with large panicles and numerous spikelets and is promoted by moderate soil drying(MD)post-anthesis.A growing body of evidence has shown that microRNAs function in regulating grain development.However,little is known about the mechanism of microRNA control of grain filling of inferior spikelets in response to MD.In this study,grain filling of inferior spikelets was promoted by MD treatment in Nipponbare.Small-RNA profiling at the most active grain-filling stage was conducted in inferior spikelets under control(CK)and MD treatment.Of 521 known and 128 novel miRNAs,38 known and 9 novel miRNAs were differentially expressed between the CK and MD treatments.Target genes of differentially expressed miRNAs were involved in multiple developmental and signaling pathways associated with catalytic activity,carbohydrate metabolism,and other functions.Both miR1861 and miR397 were upregulated by MD,leading to a decrease in OsSBDCP1 and OsLAC,two negative regulators of SSIIIa activity and BR signaling,respectively.In contrast,miR1432 abundance was reduced by MD,resulting in upregulation of OsACOT and thus an elevated content of both ABA and IAA.These results suggest that both starch synthesis and phytohormone biosynthesis are regulated by differentially expressed miRNAs in inferior spikelets in response to MD treatment.Our results suggest the molecular mechanisms by which miRNAs regulate grain filling in inferior spikelets of rice under moderate soil drying,providing potential application in agriculture to increase rice yields by genetic approaches.展开更多
Grain filling is a crucial process that affects yield in rice(Oryza sativa L.).Auxin biosynthesis and signaling are closely related to rice yield;therefore,it is important to understand the effects of auxin biosynthes...Grain filling is a crucial process that affects yield in rice(Oryza sativa L.).Auxin biosynthesis and signaling are closely related to rice yield;therefore,it is important to understand the effects of auxin biosynthesis on rice grain filling to improve crop yield.In this study,we used physiological and molecular strategies to identify the roles of auxin in rice grain filling.Exogenous application of auxin(IAA)or auxin analogues(2,4-D)to young spikelets and flag leaves improved the seed-setting rate and yield per spike.Furthermore,real-time quantitative PCR assays confirmed that nine members of the OsYUCCA family of auxin biosynthetic genes were upregulated during grain filling,implication that auxin biosynthesis plays a major role in grain development.The specific expression of either Arabidopsis AtYUCCA1 or OsYUCCA2 in the endosperm or leaves resulted in increased expression of OsIAA genes and auxin content of seeds,as well as increased grain filling and seed-setting rate.This result establishes that the auxin content in grains and leaves is important for grain development.Our findings further highlight the potential applications for improving rice yield by elevating targeted gene expression in specific tissues.展开更多
Based on isobaric tags for relative and absolute quantification(iTRAQ)technology,the proteome of grains of a maize cultivar Huangzao 4 under drought stress at grain filling stage was analyzed.The results show that und...Based on isobaric tags for relative and absolute quantification(iTRAQ)technology,the proteome of grains of a maize cultivar Huangzao 4 under drought stress at grain filling stage was analyzed.The results show that under drought stress,438 proteins were differentially expressed in the maize grains during grain filling.Among them,200 were up-regulated and 238 were down-regulated.The gene ontology(GO)analysis shows that the biological processes in which differential proteins are more involved are cellular processes,metabolic processes and single biological processes;proteins in the cell component category are mainly distributed in cells,cell parts and organelles;and the proteins the molecular function category mainly possess catalytic activity and binding function.Differentially expressed proteins classified by COG are mainly involved in protein post-translational modification and transport,molecular chaperones,general functional genes,translation,ribosomal structure,biosynthesis,energy production and transformation,carbohydrate transport and metabolism,amino acid transport and metabolism,etc.The subcellular structure of the differentially expressed proteins is mainly located in the cell chloroplast and cytosol.The proportions are 35.01%and 30.21%respectively.KEGG metabolic pathway enrichment analysis shows that the differentially expressed proteins are mostly involved in antibiotic biosynthesis,microbial metabolism in different environments,and endoplasmic reticulum protein processing;the metabolic pathways with higher enrichment are the carbon fixation pathway and estrogen signaling pathway of prokaryotes;and the higher enrichment and greater significance are in the tricarboxylic acid cycle,carbon fixation of photosynthetic organisms and proteasome.The results of this study preliminarily reveal the adaptive mechanism of maize grains in response to drought stress during grain filling,providing a theoretical reference for maize drought-resistant molecular breeding.展开更多
During grain filling,starch and other nutrients accumulate in the endosperm;this directly determines grain yield and grain quality in crops such as rice(Oryza sativa),maize(Zea mays),and wheat(Triticum aestivum).Grain...During grain filling,starch and other nutrients accumulate in the endosperm;this directly determines grain yield and grain quality in crops such as rice(Oryza sativa),maize(Zea mays),and wheat(Triticum aestivum).Grain filling is a complex trait affected by both intrinsic and environmental factors,making it difficult to explore the underlying genetics,molecular regulation,and the application of these genes for breeding.With the development of powerful genetic and molecular techniques,much has been learned about the genes and molecular networks related to grain filling over the past decades.In this review,we highlight the key factors affecting grain filling,including both biological and abiotic factors.We then summarize the key genes controlling grain filling and their roles in this event,including regulators of sugar translocation and starch biosynthesis,phytohormone-related regulators,and other factors.Finally,we discuss how the current knowledge of valuable grain filling genes could be integrated with strategies for breeding cereal varieties with improved grain yield and quality.展开更多
Grain filling influences grain size and quality in cereal crops. The molecular mechanisms that regulate grain endosperm development remain elusive. In this study, we characterized a filling-defective and grain width m...Grain filling influences grain size and quality in cereal crops. The molecular mechanisms that regulate grain endosperm development remain elusive. In this study, we characterized a filling-defective and grain width mutant, fgw1, whose mutation increased rice seed width mainly via cell division and expansion in grains. Sucrose contents were higher but starch contents lower in the fgw1 mutant during the grainfilling stage, resulting in inferior endosperm of opaque, white appearance with loosely packed starch granules. Map-based cloning revealed that FGW1 encoded a protein containing DUF630/DUF632domains, localized in the plasma membrane with preferential expression in the panicle. RNA interference in FGW1 resulted in increased grain width and weight, whereas overexpression of FGW1 led to slightly narrower kernels and better grain filling. In a yeast two-hybrid assay, FGW1 interacted directly with the 14–3–3 protein GF14f, bimolecular fluorescence complementation verified that the site of interaction was the membrane, and the mutated FGW1 protein failed to interact with GF14f. The expression of GF14f was down-regulated in fgw1, and the activities of AGPase, StSase, and SuSase in the endosperm of fgw1increased similarly to those of a reported GF14f-RNAi. Transcriptome analysis indicated that FGW1 also regulates cellular processes and carbohydrate metabolism. Thus, FGW1 regulated grain formation via the GF14f pathway.展开更多
Excessive use of nitrogen fertilizer and high planting density reduce grain weight in wheat.However,the effects of high nitrogen and planting density on the filling of grain located in different positions of the wheat...Excessive use of nitrogen fertilizer and high planting density reduce grain weight in wheat.However,the effects of high nitrogen and planting density on the filling of grain located in different positions of the wheat spikelet are unknown.A two-year field experiment was conducted to investigate this question and the underlying mechanisms with respect to hormone and carbohydrate activity.Both high nitrogen application and planting density significantly increased spike density,while reducing kernel number per spike and 1000-kernel weight.However,the effects of high nitrogen and high plant density on kernel number per spike and 1000-kernel weight were different.The inhibitory effect of high nitrogen application and high planting density on kernel number per spike was achieved mainly by a reduction in kernel number per spikelet in the top and bottom spikelets.However,the decrease in 1000-kernel weight was contributed mainly by the reduced weight of grain in the middle spikelets.The grain-filling rate of inferior grain in the middle spikelets was significantly decreased under high nitrogen input and high planting density conditions,particularly during the early and middle grain-filling periods,leading to the suppression of grain filling and consequent decrease in grain weight.This effect resulted mainly from inhibited sucrose transport to and starch accumulation in inferior grain in the middle spikelets via reduction of the abscisic acid/ethylene ratio.This mechanism may explain how high nitrogen application and high planting density inhibit the grain filling of inferior wheat grain.展开更多
To investigate the effect of nitrogen management on the grain-filling characteristics and yield formation of maize cultivars with contrasting nitrogen efficiencies,and to identify differences in grain-filling characte...To investigate the effect of nitrogen management on the grain-filling characteristics and yield formation of maize cultivars with contrasting nitrogen efficiencies,and to identify differences in grain-filling characteristics and yield of maize cultivars in response to nitrogen management,a two-year field experiment was conducted in southwest China in2015–2016.The grain-filling rate and duration of the N-inefficient cultivar XY 508 were higher than those of the N-efficient cultivar ZH 311.The 100-kernel weight of XY 508 was significantly higher than that of ZH 311.The kernel number per ear of ZH 311 was significantly higher than that of XY 508,making the population filling rate of ZH 311 significantly higher than that of XY 508.The higher population filling rate of the N-efficient maize cultivar led to a significant yield advantage over the N-inefficient maize cultivar.Nitrogen management effectively improved maize grain yield,but the response of maize cultivars with contrasting nitrogen efficiencies to nitrogen management was inconsistent.A basal fertilizer ratio 60.43%with a topdressing ratio 39.57%effectively increased grainfilling rate,delayed the time to maximum filling rate,prolonged the active filling period and effective grain-filling time,increased the 100-kernel weight,and maintained higher kernels per ear,thereby improving the population filling rate and maximizing the yield advantage of the N-efficient cultivar.A 100%basal fertilizer ratio not only increased the number of kernels per ear,but also maintained high grain filling characteristics to obtain a higher 100-kernel weight and increased the population filling rate,leading to a high grain yield in the N-inefficient cultivar.Thus,the 100%basal fertilizer ratio partially compensated for the deficient grain yield of the N-inefficient cultivar.展开更多
Understanding the morphological and physiological traits associated with improved filling efficiency in large-panicle rice varieties is critical to devise strategies for breeding programs and cultivation management pr...Understanding the morphological and physiological traits associated with improved filling efficiency in large-panicle rice varieties is critical to devise strategies for breeding programs and cultivation management practices.Information on such traits,however,remains limited.Two large-panicle varieties with high filled-grain percentage(HF) and two check large-panicle varieties with low filled-grain percentage(LF) were field-grown in 2012 and 2013.The number of spikelets per panicle of HF and LF both exceeded 300,and the filled-grain percentage(%) of HF was approximately 90,while that of LF was approximately 75 over the two years.The results showed that when the values were averaged across two years,HF yielded 12.91 ha^(-1),while LF yielded 11.01 ha^(-1).HF had a greater leaf area duration,biomass accumulation and transport of carbohydrates stored in the culm to the grains from heading to maturity compared with LF.HF exhibited a higher leaf photosynthetic rate,more green leaves on the culm,and higher root activity during filling phase,especially during the middle and late filling phases,in relative to LF.The length of HF for upper three leaves was significantly higher than that of LF,while the angle of upper three leaves on the main culm was less in both years.Meanwhile,specific leaf weight of HF was significantly higher when compared with LF.In addition,the grain filling characteristics of HF and LF were investigated in our study.Our results suggested that a higher leaf photosynthetic rate and root activity during filling phase,greater biomass accumulation and assimilate transport after heading,and longer,thicker and more erect upper three leaves were important morphological and physiological traits of HF,and these traits could be considered as selection criterion to develop large-panicle varieties with high filled-grain percentage.展开更多
Poor filling and low weight of inferior kernels limit the further improvement of wheat yield. Two cultivars, Shuangda 1 and Xinong 538, with different grain weights, were selected to investigate the physiological chan...Poor filling and low weight of inferior kernels limit the further improvement of wheat yield. Two cultivars, Shuangda 1 and Xinong 538, with different grain weights, were selected to investigate the physiological changes of inferior kernels by removal of superior kernels(RS) at the flowering stage. i TRAQ combined with physiological indexes was used to identify factors limiting the filling of inferior kernels.Removal of superior kernels significantly increased the mean filling rate of inferior kernels and thus increased their weight. A set of 6012 proteins in inferior wheat kernels were differentially expressed between the RS and control. These differentially expressed proteins were involved mainly in carbon metabolism and energy metabolism. The main reason for the promoting effect of RS on the filling of inferior kernels may be that RS downregulated proteins involved in glycolysis and pyruvate metabolism while upregulating proteins involved in carbon fixation and photosynthesis. Consequently, RS greatly increased the ATP content in inferior kernels, supplying energy for them to absorb photosynthetic assimilates. Removal of superior kernels increased the activities of sucrose synthase, soluble starch synthase,adenosine diphosphate glucose pyrophosphorylase, and starch branching enzyme in inferior kernels and promoted starch accumulation in them. Thus, RS promoted the filling of inferior kernels and increased their weight. The promoting effect of RS on starch synthesis in inferior kernels was associated with their endogenous IAA and ABA levels.展开更多
Foliar nitrogen(N)application is an effective strategy to improve protein content and quality in wheat kernels,but the specific effects of N forms remain unclear.In a two-year field study,foliar application of various...Foliar nitrogen(N)application is an effective strategy to improve protein content and quality in wheat kernels,but the specific effects of N forms remain unclear.In a two-year field study,foliar application of various N forms(NO_(3)^(-),urea,NH_(4)^(+))at anthesis was performed to measure their effects on wheat grain protein accumulation,quality formation,and the underlying mechanisms.Foliar application of three N forms showed varying effects in improving grain gluten proteins and quality traits.Under NH_(4)^(+) application,there was more post-anthesis N uptake for grain filling,with relatively strong increase in enzyme activities and gene expression associated with N metabolism in flag leaves at 8–20 days after anthesis(DAA),whereas its promotion of grain N metabolism became weaker after 20 DAA than those under NO_(3)^(-) and urea treatments.More N was remobilized from source organs to grain under treatment with foliar NO_(3)^(-) and urea.Genes controlling the synthesis of gluten protein and disulfide bonds were upregulated by NO_(3)^(-) and urea at 20–28 DAA,contributing to increased grain protein content and quality.Overall,foliar applications of NO_(3)^(-) and urea were more effective than those of NH_(4)^(+) in increasing grain N filling.These findings show that manipulating the source–sink relationship by reinforcing grain N metabolism and N remobilization is critical for optimizing grain protein accumulation and quality formation.展开更多
Variation in weather conditions during grain filling has substantial effects on maize kernel weight(KW). The objective of this work was to characterize variation in KW with sowing date-associated weather conditions an...Variation in weather conditions during grain filling has substantial effects on maize kernel weight(KW). The objective of this work was to characterize variation in KW with sowing date-associated weather conditions and examine the relationship between KW, grain filling parameters, and weather factors. Maize was sown on eight sowing dates(SD) at 15–20-day intervals from mid-March to mid-July during 2012 and 2013 in the North China Plain. With sowing date delay, KW increased initially and later declined, and the greatest KW was obtained at SD6 in both years. The increased KW at SD6 was attributed mainly to kernel growth rate(Gmean), and effective grain-filling period(P). Variations in temperature and radiation were the primary factors that influenced KW and grain-filling parameters. When the effective cumulative temperature(AT) and radiation(Ra)during grain filling were 950 °C and 1005.4 MJ m-2, respectively, P and KW were greatest. High temperatures(daily maximum temperature [Tmax] > 30.2 °C) during grain filling under early sowing conditions, or low temperatures(daily minimum temperature [Tmin] < 20.7 °C) under late sowing conditions combined with high diurnal temperature range(Tmax-min> 7.1 °C) decreased kernel growth rate and ultimately final KW. When sowing was performed from May 25 through June 27, higher KW and yield of maize were obtained. We conclude that variations in environmental conditions(temperature and radiation) during grain filling markedly affect growth rate and duration of grain filling and eventually affect kernel weight and yield of maize.展开更多
Simultaneous occurrence of drought and heat stress will have significant negative impact on rice yield,especially under upland conditions.The projected increase in global temperatures and reduced precipitation will in...Simultaneous occurrence of drought and heat stress will have significant negative impact on rice yield,especially under upland conditions.The projected increase in global temperatures and reduced precipitation will increase the frequency of occurrence and intensity of these stresses,threatening rice production.Despite recognizing the importance of combined stress in rice,the knowledge generated in this area is very limited.Though complex,understanding combined stress tolerance of rice under water saving cultivation is more critical towards development of climate resilient rice cultivars.Here,we summarized the effects of combined stress on rice physiology with more emphasis on reproductive stage.Omics responses,phenotyping and physiology challenges and potential strategies for improving combined stress tolerance in rice are also discussed.展开更多
Spatial dynamics of crop yield provide useful information for improving the production. High sensitivity of crop growth models to uncertainties in input factors and parameters and relatively coarse parameterizations i...Spatial dynamics of crop yield provide useful information for improving the production. High sensitivity of crop growth models to uncertainties in input factors and parameters and relatively coarse parameterizations in conventional remote sensing(RS) approaches limited their applications over broad regions. In this study, a process-based and remote sensing driven crop yield model for maize(PRYM–Maize) was developed to estimate regional maize yield, and it was implemented using eight data-model coupling strategies(DMCSs) over the Northeast China Plain(NECP). Simulations under eight DMCSs were validated against the prefecture-level statistics(2010–2012) reported by National Bureau of Statistics of China, and inter-compared. The 3-year averaged result could give more robust estimate than the yearly simulation for maize yield over space. A 3-year averaged validation showed that prefecture-level estimates by PRYM–Maize under DMCS8, which coupled with the development stage(DVS)-based grain-filling algorithm and RS phenology information and leaf area index(LAI), had higher correlation(R, 0.61) and smaller root mean standard error(RMSE, 1.33 t ha^(–1)) with the statistics than did PRYM–Maize under other DMCSs. The result also demonstrated that DVS-based grain-filling algorithm worked better for maize yield than did the harvest index(HI)-based method, and both RS phenology information and LAI worked for improving regional maize yield estimate. These results demonstrate that the developed PRYM–Maize under DMCS8 gives reasonable estimates for maize yield and provides scientific basis facilitating the understanding the spatial variations of maize yield over the NECP.展开更多
Grain development is a crucial determinant of yield and quality in bread wheat(Triticum aestivum L.).However,the regulatory mechanisms underlying wheat grain development remain elusive.Here we report how Ta MADS29 int...Grain development is a crucial determinant of yield and quality in bread wheat(Triticum aestivum L.).However,the regulatory mechanisms underlying wheat grain development remain elusive.Here we report how Ta MADS29 interacts with Ta NF-YB1 to synergistically regulate early grain development in bread wheat.The tamads29 mutants generated by CRISPR/Cas9 exhibited severe grain filling deficiency,coupled with excessive accumulation of reactive oxygen species(ROS)and abnormal programmed cell death that occurred in early developing grains,while overexpression of Ta MADS29 increased grain width and1,000-kernel weight.Further analysis revealed that Ta MADS29 interacted directly with Ta NF-YB1;null mutation in Ta NF-YB1caused grain developmental deficiency similar to tamads29 mutants.The regulatory complex composed of Ta MADS29 and Ta NF-YB1 exercises its possible function that inhibits the excessive accumulation of ROS by regulating the genes involved in chloroplast development and photosynthesis in early developing wheat grains and prevents nucellar projection degradation and endosperm cell death,facilitating transportation of nutrients into the endosperm and wholly filling of developing grains.Collectively,our work not only discloses the molecular mechanism of MADS-box and NF-Y TFs in facilitating bread wheat grain development,but also indicates that caryopsis chloroplast might be a central regulator of grain development rather than merely a photosynthesis organelle.More importantly,our work offers an innovative way to breed high-yield wheat cultivars by controlling the ROS level in developing grains.展开更多
基金supported by the National Key R&D Program of China(2016YFD0300103 and 2017YFD0300506)the Heilongjiang Provincial Funding for National Key R&D Programs of China(GX18B029)the“Academic Backbone”Project of Northeast Agricultural University,China(17XG23)。
文摘Now,lodging is a major constraint factor contributing to yield loss of maize (Zea mays L.) under high planting density.Chemical regulation and nitrogen fertilizer could effectively coordinate the relationship between stem lodging and maize yield,which significantly reduce lodging and improve the grain yield.The purpose of this study was to explore the effects of chemical regulation and different nitrogen application rates on lodging characteristics,grain filling and yield of maize under high density.For this,we established a field study during 2017 and 2018 growing seasons,with three nitrogen levels of N100 (100 kg ha^(–1)),N200 (200 kg ha^(–1)) and N300 (300 kg ha^(–1)) at high planting density (90 000 plants ha^(–1)),and applied plant growth regulator (Yuhuangjin,the mixture of 3% DTA-6 and 27% ethephon) at the 7th leaf.The results showed that chemical control increased the activities of phenylalanine ammonia-lyase (PAL),tyrosine ammonia-lyase (TAL),4-coumarate:Co A ligase (4CL),and cinnamyl alcohol dehydrogenase (CAD),and increased the lignin,cellulose and hemicellulose contents at the bottom of the 3rd internode,which significantly reduced the lodging percentage.The lignin-related enzyme activities,lignin,cellulose and hemicellulose contents decreased with the increase of nitrogen fertilizer,which significantly increased the lodging percentage.The 200 kg ha^(–1) nitrogen application and chemical control increased the number,diameter,angle,volume,and dry weight of brace roots.The 200 kg ha^(–1) nitrogen application and chemical control significantly increased the activities of ADP-glucose pyrophosphorylase (AGPase),soluble starch synthase (SSS) and starch branching enzyme(SBE),which promoted the starch accumulation in grains.Additional,improved the maximum grain filling rate (V_(max)) and mean grain filling rate (V_(m)),which promoted the grain filling process,significantly increased grain weight and grain number per ear,thus increased the final yield.
基金funding support from the National Key Research and Development Program of China(2018YFD0301206,2016YFD0300209,2016YFD0300307,and 2017YFD0301704)。
文摘Grain water relations play an important role in grain filling in maize. The study aimed to gain a clear understanding of the changes in grain dry weight and water relations in maize grains by using hybrids with contrasting nitrogen efficiencies under differing nitrogen levels. The objectives were: 1) to understand the changes in dry matter and percent moisture content(MC) during grain development in response to different nitrogen application rates and 2) to determine whether nitrogen application affects grain filling by regulating grain water relations. Two maize hybrids, high N-efficient Zhenghong 311(ZH311) and low N-efficient Xianyu 508(XY508), were grown in the field under four levels of N fertilizer: 0, 150, 300, and 450 kg N ha;during three growing seasons. Dry weight, percent MC and water content(WC) of basal-middle and apical grains were investigated. The difference in the maximum WC and filling duration of basal-middle and apical grains in maize ears resulted in a significant difference in final grain weight. Grain position markedly influenced grain drying down;specifically, the drying down rate of apical grains was faster than that of basal-middle grains. Genotype and grain position both influenced the impact of nitrogen application rate on grain filling and drying down. Nitrogen rate determined the maximum grain WC and percent MC loss rate in the middle and the late grain-filling stages, thus affecting final grain weight. The use of high N-efficient hybrids, combined with the reduction of nitrogen application rate, can coordinate basal-middle and apical grain drying down to ensure yield. This management strategy could lead to a win-win situation in which the maximum maize yield, efficient mechanical harvest and environmental safety are all achieved.
基金the National Key Research Program of China(Grant No.2016YFD0300503)the National Rice Industry Technology System of China(Grant No.CARS0127)+3 种基金the National Natural Science Foundation of China(Grant No.31971841)he Key Research Program of Jiangsu Province,China(Grant No.BE2018355)the Earmarked Fund for Jiangsu Agricultural Industry Technology System,China(Grant No.JATS[2020]450)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China.
文摘The environmental temperature occurring during the grain filling stage is an important factoraffecting starch synthesis and accumulation in rice. We investigated starch accumulation, amylaseactivity and starch granule size distribution in two low-amylose japonica rice varieties, Nanjing 9108 andFujing 1606, grown in the field at different filling temperatures by manipulating sowing date. The two ricevarieties exhibited similar performances between two sowing dates. Total starch, amylose andamylopectin contents were lower at the early-filling stage of T1 treatment (Early-sowing) compared withthose at the same stage in T2 treatment (Late-sowing). In contrast, at the late-filling stage, when fieldtemperatures were generally decreasing, total starch and amylopectin contents in T1 were highercompared to those in T2. The ideal temperature for strong activity of ADP-glucose pyrophosphorylaseand soluble starch synthase was about 22℃. A higher temperature from the heading to maturity stagesin T1 increased the activities of starch branching enzyme and suppressed the activities of granule boundstarch synthetase and starch debranching enzyme. We found that rice produced larger-sized starchgranules under the T1 treatment. These results suggested that due to the early-sowing date, the hightemperature (30℃) occurring at the early-filling stage hindered starch synthesis and accumulation,however, the lower temperatures (22 ℃) at the late-filling stage allowed starch synthesis and accumulationto return to normal levels.
基金supported by the National Natural Science Foundation of China(32171927,31971924,U21A201755)the Natural Science Foundation of Hunan Province(2021JJ30349)+3 种基金the Key Research and Development Program of Hunan Province(2018NK1010)Science and Technology Plan of Changsha City(kq2004034)Scientific Research Project of Education Department of Hunan Province(19A245)the Hong Kong Research Grant Council(AoE/M-05/12,AoE/M-403/16,GRF12103219,12103220,14177617).
文摘The grain filling of inferior spikelets is much less complete than that of superior spikelets in rice cultivars with large panicles and numerous spikelets and is promoted by moderate soil drying(MD)post-anthesis.A growing body of evidence has shown that microRNAs function in regulating grain development.However,little is known about the mechanism of microRNA control of grain filling of inferior spikelets in response to MD.In this study,grain filling of inferior spikelets was promoted by MD treatment in Nipponbare.Small-RNA profiling at the most active grain-filling stage was conducted in inferior spikelets under control(CK)and MD treatment.Of 521 known and 128 novel miRNAs,38 known and 9 novel miRNAs were differentially expressed between the CK and MD treatments.Target genes of differentially expressed miRNAs were involved in multiple developmental and signaling pathways associated with catalytic activity,carbohydrate metabolism,and other functions.Both miR1861 and miR397 were upregulated by MD,leading to a decrease in OsSBDCP1 and OsLAC,two negative regulators of SSIIIa activity and BR signaling,respectively.In contrast,miR1432 abundance was reduced by MD,resulting in upregulation of OsACOT and thus an elevated content of both ABA and IAA.These results suggest that both starch synthesis and phytohormone biosynthesis are regulated by differentially expressed miRNAs in inferior spikelets in response to MD treatment.Our results suggest the molecular mechanisms by which miRNAs regulate grain filling in inferior spikelets of rice under moderate soil drying,providing potential application in agriculture to increase rice yields by genetic approaches.
基金supported by the National Natural Science Foundation of China(Grant Nos.31801193,31820103008,91754104,and 31670283)the Fundamental Research Funds for the Central Universities(No.lzujbky-2020-it13).
文摘Grain filling is a crucial process that affects yield in rice(Oryza sativa L.).Auxin biosynthesis and signaling are closely related to rice yield;therefore,it is important to understand the effects of auxin biosynthesis on rice grain filling to improve crop yield.In this study,we used physiological and molecular strategies to identify the roles of auxin in rice grain filling.Exogenous application of auxin(IAA)or auxin analogues(2,4-D)to young spikelets and flag leaves improved the seed-setting rate and yield per spike.Furthermore,real-time quantitative PCR assays confirmed that nine members of the OsYUCCA family of auxin biosynthetic genes were upregulated during grain filling,implication that auxin biosynthesis plays a major role in grain development.The specific expression of either Arabidopsis AtYUCCA1 or OsYUCCA2 in the endosperm or leaves resulted in increased expression of OsIAA genes and auxin content of seeds,as well as increased grain filling and seed-setting rate.This result establishes that the auxin content in grains and leaves is important for grain development.Our findings further highlight the potential applications for improving rice yield by elevating targeted gene expression in specific tissues.
基金National Key R&D Program of China(2018YFD0100105)Natural Science Foundation of Guangxi(2015GXNSFBA139061)+1 种基金Special Fund for Innovation-driven Development in Guangxi(Gui Ke AA17204064)Guangxi Innovative Team Construction Project of National Modern Agricultural Industrial Technology System(nycytxgxcxtd).
文摘Based on isobaric tags for relative and absolute quantification(iTRAQ)technology,the proteome of grains of a maize cultivar Huangzao 4 under drought stress at grain filling stage was analyzed.The results show that under drought stress,438 proteins were differentially expressed in the maize grains during grain filling.Among them,200 were up-regulated and 238 were down-regulated.The gene ontology(GO)analysis shows that the biological processes in which differential proteins are more involved are cellular processes,metabolic processes and single biological processes;proteins in the cell component category are mainly distributed in cells,cell parts and organelles;and the proteins the molecular function category mainly possess catalytic activity and binding function.Differentially expressed proteins classified by COG are mainly involved in protein post-translational modification and transport,molecular chaperones,general functional genes,translation,ribosomal structure,biosynthesis,energy production and transformation,carbohydrate transport and metabolism,amino acid transport and metabolism,etc.The subcellular structure of the differentially expressed proteins is mainly located in the cell chloroplast and cytosol.The proportions are 35.01%and 30.21%respectively.KEGG metabolic pathway enrichment analysis shows that the differentially expressed proteins are mostly involved in antibiotic biosynthesis,microbial metabolism in different environments,and endoplasmic reticulum protein processing;the metabolic pathways with higher enrichment are the carbon fixation pathway and estrogen signaling pathway of prokaryotes;and the higher enrichment and greater significance are in the tricarboxylic acid cycle,carbon fixation of photosynthetic organisms and proteasome.The results of this study preliminarily reveal the adaptive mechanism of maize grains in response to drought stress during grain filling,providing a theoretical reference for maize drought-resistant molecular breeding.
基金supported by the National Natural Science Foundation of China(32100206,31871217,and 32072037)the China National Postdoctoral Program for Innovative Talents(BX2021314)+2 种基金the China Postdoctoral Science Foundation(2021M693173)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(20KJA210002)Yangzhou University Interdisciplinary Research Foundation for Crop Science Discipline of Targeted Support(yzuxk202006)。
文摘During grain filling,starch and other nutrients accumulate in the endosperm;this directly determines grain yield and grain quality in crops such as rice(Oryza sativa),maize(Zea mays),and wheat(Triticum aestivum).Grain filling is a complex trait affected by both intrinsic and environmental factors,making it difficult to explore the underlying genetics,molecular regulation,and the application of these genes for breeding.With the development of powerful genetic and molecular techniques,much has been learned about the genes and molecular networks related to grain filling over the past decades.In this review,we highlight the key factors affecting grain filling,including both biological and abiotic factors.We then summarize the key genes controlling grain filling and their roles in this event,including regulators of sugar translocation and starch biosynthesis,phytohormone-related regulators,and other factors.Finally,we discuss how the current knowledge of valuable grain filling genes could be integrated with strategies for breeding cereal varieties with improved grain yield and quality.
基金sponsored by the National Key Research and Development Program of China(2022YFD1201600, 2016YFD0100501)Natural Science Foundation of Chongqing of China (cstc2020jcyj-msxm0539)+1 种基金the National Natural Science Foundation of China (32171964)Chongqing Natural Science Foundation Innovation Group (cstc2021jcyjcxttX0004)。
文摘Grain filling influences grain size and quality in cereal crops. The molecular mechanisms that regulate grain endosperm development remain elusive. In this study, we characterized a filling-defective and grain width mutant, fgw1, whose mutation increased rice seed width mainly via cell division and expansion in grains. Sucrose contents were higher but starch contents lower in the fgw1 mutant during the grainfilling stage, resulting in inferior endosperm of opaque, white appearance with loosely packed starch granules. Map-based cloning revealed that FGW1 encoded a protein containing DUF630/DUF632domains, localized in the plasma membrane with preferential expression in the panicle. RNA interference in FGW1 resulted in increased grain width and weight, whereas overexpression of FGW1 led to slightly narrower kernels and better grain filling. In a yeast two-hybrid assay, FGW1 interacted directly with the 14–3–3 protein GF14f, bimolecular fluorescence complementation verified that the site of interaction was the membrane, and the mutated FGW1 protein failed to interact with GF14f. The expression of GF14f was down-regulated in fgw1, and the activities of AGPase, StSase, and SuSase in the endosperm of fgw1increased similarly to those of a reported GF14f-RNAi. Transcriptome analysis indicated that FGW1 also regulates cellular processes and carbohydrate metabolism. Thus, FGW1 regulated grain formation via the GF14f pathway.
基金This work was supported by the National Natural Science Foundation of China(31871567)the National Key Research and Development Program of China(2017YFD0300202-2)the Young Scholar of Tang(2017).
文摘Excessive use of nitrogen fertilizer and high planting density reduce grain weight in wheat.However,the effects of high nitrogen and planting density on the filling of grain located in different positions of the wheat spikelet are unknown.A two-year field experiment was conducted to investigate this question and the underlying mechanisms with respect to hormone and carbohydrate activity.Both high nitrogen application and planting density significantly increased spike density,while reducing kernel number per spike and 1000-kernel weight.However,the effects of high nitrogen and high plant density on kernel number per spike and 1000-kernel weight were different.The inhibitory effect of high nitrogen application and high planting density on kernel number per spike was achieved mainly by a reduction in kernel number per spikelet in the top and bottom spikelets.However,the decrease in 1000-kernel weight was contributed mainly by the reduced weight of grain in the middle spikelets.The grain-filling rate of inferior grain in the middle spikelets was significantly decreased under high nitrogen input and high planting density conditions,particularly during the early and middle grain-filling periods,leading to the suppression of grain filling and consequent decrease in grain weight.This effect resulted mainly from inhibited sucrose transport to and starch accumulation in inferior grain in the middle spikelets via reduction of the abscisic acid/ethylene ratio.This mechanism may explain how high nitrogen application and high planting density inhibit the grain filling of inferior wheat grain.
基金supported by the National Key Research and Development Program of China(2016YFD0300307 and 2016YFD0300209)the Special Fund for Agro-scientific Research in the Public Interest of China(20150312705)the Sichuan Agriculture Research System of Maize Industry。
文摘To investigate the effect of nitrogen management on the grain-filling characteristics and yield formation of maize cultivars with contrasting nitrogen efficiencies,and to identify differences in grain-filling characteristics and yield of maize cultivars in response to nitrogen management,a two-year field experiment was conducted in southwest China in2015–2016.The grain-filling rate and duration of the N-inefficient cultivar XY 508 were higher than those of the N-efficient cultivar ZH 311.The 100-kernel weight of XY 508 was significantly higher than that of ZH 311.The kernel number per ear of ZH 311 was significantly higher than that of XY 508,making the population filling rate of ZH 311 significantly higher than that of XY 508.The higher population filling rate of the N-efficient maize cultivar led to a significant yield advantage over the N-inefficient maize cultivar.Nitrogen management effectively improved maize grain yield,but the response of maize cultivars with contrasting nitrogen efficiencies to nitrogen management was inconsistent.A basal fertilizer ratio 60.43%with a topdressing ratio 39.57%effectively increased grainfilling rate,delayed the time to maximum filling rate,prolonged the active filling period and effective grain-filling time,increased the 100-kernel weight,and maintained higher kernels per ear,thereby improving the population filling rate and maximizing the yield advantage of the N-efficient cultivar.A 100%basal fertilizer ratio not only increased the number of kernels per ear,but also maintained high grain filling characteristics to obtain a higher 100-kernel weight and increased the population filling rate,leading to a high grain yield in the N-inefficient cultivar.Thus,the 100%basal fertilizer ratio partially compensated for the deficient grain yield of the N-inefficient cultivar.
基金financed by the Special Program of Super Rice of Ministry of Agriculture, China (02318802013231)the National Public Services Sectors (Agricultural) Research Projects, Ministry of Agriculture, China (201303102)the Great Technology Project of Ningbo, China (2013C11001)
文摘Understanding the morphological and physiological traits associated with improved filling efficiency in large-panicle rice varieties is critical to devise strategies for breeding programs and cultivation management practices.Information on such traits,however,remains limited.Two large-panicle varieties with high filled-grain percentage(HF) and two check large-panicle varieties with low filled-grain percentage(LF) were field-grown in 2012 and 2013.The number of spikelets per panicle of HF and LF both exceeded 300,and the filled-grain percentage(%) of HF was approximately 90,while that of LF was approximately 75 over the two years.The results showed that when the values were averaged across two years,HF yielded 12.91 ha^(-1),while LF yielded 11.01 ha^(-1).HF had a greater leaf area duration,biomass accumulation and transport of carbohydrates stored in the culm to the grains from heading to maturity compared with LF.HF exhibited a higher leaf photosynthetic rate,more green leaves on the culm,and higher root activity during filling phase,especially during the middle and late filling phases,in relative to LF.The length of HF for upper three leaves was significantly higher than that of LF,while the angle of upper three leaves on the main culm was less in both years.Meanwhile,specific leaf weight of HF was significantly higher when compared with LF.In addition,the grain filling characteristics of HF and LF were investigated in our study.Our results suggested that a higher leaf photosynthetic rate and root activity during filling phase,greater biomass accumulation and assimilate transport after heading,and longer,thicker and more erect upper three leaves were important morphological and physiological traits of HF,and these traits could be considered as selection criterion to develop large-panicle varieties with high filled-grain percentage.
基金supported by the National Natural Science Foundation of China (31871567)the National Key Research and Development Program of China (2017YFD0300202-2)Tang Young Scholar (2017)。
文摘Poor filling and low weight of inferior kernels limit the further improvement of wheat yield. Two cultivars, Shuangda 1 and Xinong 538, with different grain weights, were selected to investigate the physiological changes of inferior kernels by removal of superior kernels(RS) at the flowering stage. i TRAQ combined with physiological indexes was used to identify factors limiting the filling of inferior kernels.Removal of superior kernels significantly increased the mean filling rate of inferior kernels and thus increased their weight. A set of 6012 proteins in inferior wheat kernels were differentially expressed between the RS and control. These differentially expressed proteins were involved mainly in carbon metabolism and energy metabolism. The main reason for the promoting effect of RS on the filling of inferior kernels may be that RS downregulated proteins involved in glycolysis and pyruvate metabolism while upregulating proteins involved in carbon fixation and photosynthesis. Consequently, RS greatly increased the ATP content in inferior kernels, supplying energy for them to absorb photosynthetic assimilates. Removal of superior kernels increased the activities of sucrose synthase, soluble starch synthase,adenosine diphosphate glucose pyrophosphorylase, and starch branching enzyme in inferior kernels and promoted starch accumulation in them. Thus, RS promoted the filling of inferior kernels and increased their weight. The promoting effect of RS on starch synthesis in inferior kernels was associated with their endogenous IAA and ABA levels.
基金supported by the National Natural Science Foundation of China(31971860).
文摘Foliar nitrogen(N)application is an effective strategy to improve protein content and quality in wheat kernels,but the specific effects of N forms remain unclear.In a two-year field study,foliar application of various N forms(NO_(3)^(-),urea,NH_(4)^(+))at anthesis was performed to measure their effects on wheat grain protein accumulation,quality formation,and the underlying mechanisms.Foliar application of three N forms showed varying effects in improving grain gluten proteins and quality traits.Under NH_(4)^(+) application,there was more post-anthesis N uptake for grain filling,with relatively strong increase in enzyme activities and gene expression associated with N metabolism in flag leaves at 8–20 days after anthesis(DAA),whereas its promotion of grain N metabolism became weaker after 20 DAA than those under NO_(3)^(-) and urea treatments.More N was remobilized from source organs to grain under treatment with foliar NO_(3)^(-) and urea.Genes controlling the synthesis of gluten protein and disulfide bonds were upregulated by NO_(3)^(-) and urea at 20–28 DAA,contributing to increased grain protein content and quality.Overall,foliar applications of NO_(3)^(-) and urea were more effective than those of NH_(4)^(+) in increasing grain N filling.These findings show that manipulating the source–sink relationship by reinforcing grain N metabolism and N remobilization is critical for optimizing grain protein accumulation and quality formation.
基金supported by the Special Fund for Agro-scientific Research in the Public Interest(No.201203096)the National Key Technology R&D Program of China(Nos.2013BAD07B00 and 2013BAD08B00)the China Agriculture Research System(No.CARS-02)
文摘Variation in weather conditions during grain filling has substantial effects on maize kernel weight(KW). The objective of this work was to characterize variation in KW with sowing date-associated weather conditions and examine the relationship between KW, grain filling parameters, and weather factors. Maize was sown on eight sowing dates(SD) at 15–20-day intervals from mid-March to mid-July during 2012 and 2013 in the North China Plain. With sowing date delay, KW increased initially and later declined, and the greatest KW was obtained at SD6 in both years. The increased KW at SD6 was attributed mainly to kernel growth rate(Gmean), and effective grain-filling period(P). Variations in temperature and radiation were the primary factors that influenced KW and grain-filling parameters. When the effective cumulative temperature(AT) and radiation(Ra)during grain filling were 950 °C and 1005.4 MJ m-2, respectively, P and KW were greatest. High temperatures(daily maximum temperature [Tmax] > 30.2 °C) during grain filling under early sowing conditions, or low temperatures(daily minimum temperature [Tmin] < 20.7 °C) under late sowing conditions combined with high diurnal temperature range(Tmax-min> 7.1 °C) decreased kernel growth rate and ultimately final KW. When sowing was performed from May 25 through June 27, higher KW and yield of maize were obtained. We conclude that variations in environmental conditions(temperature and radiation) during grain filling markedly affect growth rate and duration of grain filling and eventually affect kernel weight and yield of maize.
基金SERB,DST,Govt.of India,for National Post-Doctoral fellowship(PDF/2018/003582)Ramanujan Fellowship(SE/S2/RJN-039/2016)Early Career Research Award(ECR/2018/00l942).
文摘Simultaneous occurrence of drought and heat stress will have significant negative impact on rice yield,especially under upland conditions.The projected increase in global temperatures and reduced precipitation will increase the frequency of occurrence and intensity of these stresses,threatening rice production.Despite recognizing the importance of combined stress in rice,the knowledge generated in this area is very limited.Though complex,understanding combined stress tolerance of rice under water saving cultivation is more critical towards development of climate resilient rice cultivars.Here,we summarized the effects of combined stress on rice physiology with more emphasis on reproductive stage.Omics responses,phenotyping and physiology challenges and potential strategies for improving combined stress tolerance in rice are also discussed.
基金supported by the National Key Research and Development Program of China(2016YFD0300101,and 2016YFD0300110)the National Natural Science Foundation of China(41871253 and 31671585)+1 种基金the“Taishan Scholar”Project of Shandong Province,Chinathe Key Basic Research Project of Shandong Natural Science Foundation,China(ZR2017ZB0422)。
文摘Spatial dynamics of crop yield provide useful information for improving the production. High sensitivity of crop growth models to uncertainties in input factors and parameters and relatively coarse parameterizations in conventional remote sensing(RS) approaches limited their applications over broad regions. In this study, a process-based and remote sensing driven crop yield model for maize(PRYM–Maize) was developed to estimate regional maize yield, and it was implemented using eight data-model coupling strategies(DMCSs) over the Northeast China Plain(NECP). Simulations under eight DMCSs were validated against the prefecture-level statistics(2010–2012) reported by National Bureau of Statistics of China, and inter-compared. The 3-year averaged result could give more robust estimate than the yearly simulation for maize yield over space. A 3-year averaged validation showed that prefecture-level estimates by PRYM–Maize under DMCS8, which coupled with the development stage(DVS)-based grain-filling algorithm and RS phenology information and leaf area index(LAI), had higher correlation(R, 0.61) and smaller root mean standard error(RMSE, 1.33 t ha^(–1)) with the statistics than did PRYM–Maize under other DMCSs. The result also demonstrated that DVS-based grain-filling algorithm worked better for maize yield than did the harvest index(HI)-based method, and both RS phenology information and LAI worked for improving regional maize yield estimate. These results demonstrate that the developed PRYM–Maize under DMCS8 gives reasonable estimates for maize yield and provides scientific basis facilitating the understanding the spatial variations of maize yield over the NECP.
基金supported by the National Key Research and Development Program of China(2022YFF1002902,2016YFD0100803)。
文摘Grain development is a crucial determinant of yield and quality in bread wheat(Triticum aestivum L.).However,the regulatory mechanisms underlying wheat grain development remain elusive.Here we report how Ta MADS29 interacts with Ta NF-YB1 to synergistically regulate early grain development in bread wheat.The tamads29 mutants generated by CRISPR/Cas9 exhibited severe grain filling deficiency,coupled with excessive accumulation of reactive oxygen species(ROS)and abnormal programmed cell death that occurred in early developing grains,while overexpression of Ta MADS29 increased grain width and1,000-kernel weight.Further analysis revealed that Ta MADS29 interacted directly with Ta NF-YB1;null mutation in Ta NF-YB1caused grain developmental deficiency similar to tamads29 mutants.The regulatory complex composed of Ta MADS29 and Ta NF-YB1 exercises its possible function that inhibits the excessive accumulation of ROS by regulating the genes involved in chloroplast development and photosynthesis in early developing wheat grains and prevents nucellar projection degradation and endosperm cell death,facilitating transportation of nutrients into the endosperm and wholly filling of developing grains.Collectively,our work not only discloses the molecular mechanism of MADS-box and NF-Y TFs in facilitating bread wheat grain development,but also indicates that caryopsis chloroplast might be a central regulator of grain development rather than merely a photosynthesis organelle.More importantly,our work offers an innovative way to breed high-yield wheat cultivars by controlling the ROS level in developing grains.
