Water caltrop(Trapa spp.,Lythraceae)is a traditional but currently underutilized non-cereal crop.Here,we generated chromosome-level genome assemblies for the two diploid progenitors of allotetraploid Trapa.natans(4x,A...Water caltrop(Trapa spp.,Lythraceae)is a traditional but currently underutilized non-cereal crop.Here,we generated chromosome-level genome assemblies for the two diploid progenitors of allotetraploid Trapa.natans(4x,AABB),i.e.,diploid T.natans(2x,AA)and Trapa incisa(2x,BB).In conjunction with four published(sub)genomes of Trapa,we used gene-based and graph-based pangenomic approaches and a pangenomic transposable element(TE)library to develop Trapa genomic resources.The pangenome displayed substantial gene-content variationwith dispensable and private gene clusters occupying a large proportion(51.95%)of the total cluster sets in the six(sub)genomes.Genotyping of presence-absence variation(PAVs)identified 40453 PAVs associated with 2570 genes specific to A-or B-lineages,of which 1428were differentially expressed,andwere enriched in organ development process,organic substancemetabolic process and response to stimulus.Comparative genome analyses showed that the allotetraploid T.natans underwent asymmetric subgenome divergence,with the B-subgenome being more dominant than the A-subgenome.Multiple factors,including PAVs,asymmetrical amplification of TEs,homeologous exchanges(HEs),and homeolog expression divergence,together affected genome evolution after polyploidization.Overall,this study sheds lights on the genome architecture and evolution of Trapa,and facilitates its functional genomic studies and breeding program.展开更多
To explore how rice(Oryza sativa L.) can be safely produced in Cd-polluted soil, OsLCT1 and OsNramp5 mutant lines were generated by CRISPR/Cas9-mediated mutagenesis. One of OsLCT1 mutant(lct1×1) and two of OsNram...To explore how rice(Oryza sativa L.) can be safely produced in Cd-polluted soil, OsLCT1 and OsNramp5 mutant lines were generated by CRISPR/Cas9-mediated mutagenesis. One of OsLCT1 mutant(lct1×1) and two of OsNramp5 mutants(nramp5×7 and nramp5×9) were evaluated for grain Cd accumulation and agronomic performances. In paddy field soil containing approximately 0.9 mg/kg Cd, lct1×1 grains contained approximately 40%(0.17 mg/kg) of the Cd concentration of the wild type parental line, less than the China National Food Safety Standard(0.20 mg/kg). Both OsNramp5 mutants showed low grain Cd accumulation(< 0.06 mg/kg) in the paddy(approximately 0.9 mg/kg Cd) or in pots in soil spiked with 2 mg/kg Cd. However, only nramp5×7 showed normal growth and yield, whereas the growth of nramp5×9 was severely impaired. The study showed that lct1×1 could be used to produce rice grains safe for human consumption in lightly contaminated paddy soils and nramp5×7 used in soils contaminated by much higher levels of Cd.展开更多
A field demonstration of reduction of lead availability in a soil and cabbage (Brassica Chinensis L.) contaminated by mining tailings, located in Shaoxing, China was carried out to evaluate the effects of applications...A field demonstration of reduction of lead availability in a soil and cabbage (Brassica Chinensis L.) contaminated by mining tailings, located in Shaoxing, China was carried out to evaluate the effects of applications of phosphorus fertilizers on Pb fractionation and Pb phytoavailability in the soil. It was found that the addition of all three P fertilizers including single super phosphate (SSP), phosphate rock (PR), and calcium magnesium phosphate (CMP) significantly decreased the percentage of water-soluble and exchangeable (WE) soil Pb and then reduced the uptake of Pb, Cd, and Zn by the cabbage compared to the control (CK). The results showed that the level of 300 g P/m2 soil was the most cost-effective application rate of P fertilizers for reducing Pb availability at the first stage of remediation, and that at this P level, the effect of WE fraction of Pb in the soil de- creased by three phosphorus fertilizers followed the order: CMP (79%)>SSP (41%)>PR (23%); Effectiveness on the reduction of Pb uptake by cabbage was in the order: CMP (53%)>SSP (41%)>PR (30%). Therefore our field trial demonstrated that it was effective and feasible to reduce Pb availability in soil and cabbage contaminated by mining tailings using P fertilizers in China and PR would be a most cost-effective amendment.展开更多
To understand the relationship between rice sowing date and occurrence of the rice small brown planthopper （SBPH） Laodelphax striatellus Fallen and the epidemics of the planthopper-transmitted rice stripe viral （RS...To understand the relationship between rice sowing date and occurrence of the rice small brown planthopper （SBPH） Laodelphax striatellus Fallen and the epidemics of the planthopper-transmitted rice stripe viral （RSV） disease, four sowing dates of rice were evaluated in 2006 and 2007. The results showed that the peak density of SBPH and RSV incidence in the nursery and in the transplanted field decreased with the delay of sowing date in single crop of japonica rice in north Zhejiang Province of China. The relationship between seedling RSV incidence at the end of the nursery trial with sowing date was well described by Weibull equation. The area under the curve of population dynamics （AUCPD or planthopper-day accumulation） or the peak density of the planthopper in the nursery could be summarized by a logistic equation. RSV incidence in the transplanted fields could be characterized quantitatively by a multivariate regression equation, including the variables of sowing date, peak density of the vector, and RSV incidence at the end of the nursery trial. That the descriptive model excluded the AUCPD in transplanted field implies that this variable is not necessary in forecasting disease epidemics in the field. The 2-year experiments sufficiently indicated that suitable sowing of rice could be used as one of the effective measures to control the vector population and therefore the planthopper-transmitted RSV on a larger scale. The optimal sowing date for the single-cropped transplanted japonica rice is recommended from late May to early June in north Zhejiang, China.展开更多
A pot experiment was conducted to study the effects of Cd on grain Cd, K, P, Mg, Zn, Cu, Pb, Fe and Mn accumulation in two rice genotypes （Xiushui 63 and Xiushui 217） differing in grain Cd accumulation under four Cd...A pot experiment was conducted to study the effects of Cd on grain Cd, K, P, Mg, Zn, Cu, Pb, Fe and Mn accumulation in two rice genotypes （Xiushui 63 and Xiushui 217） differing in grain Cd accumulation under four Cd levels, i.e. 0, 0.5, 2.5 and 12.5 mg/kg. Rice genotype greatly affected the grain K content, but not significantly for P, Mg, Zn, Cu, Pb, Fe and Mn contents. There were remarkable effects of additional Cd on the contents of P, Mg and Zn in grains, while not significant for K, Cu, Pb, Fe and Mn contents. No significant differences were found in the interaction of genotype by additional Cd on these nine element contents. The low grain Cd accumulation genotype Xiushui 217 had significantly higher grain K, Mg, Cu and Mn contents than the high grain Cd accumulation genotype Xiushui 63, but the case was opposite for Zn, Pb and Fe contents. It also showed that Cd addition levels significantly influenced the K, P, Mg, Zn, Cu, Pb, Fe and Mn contents in rice grains. Grain K, P, Mg, Zn, Fe and Mn contents reduced with the increasing rate of Cd addition.展开更多
The effect of H2O2 pretreatment on Cd tolerance and translocation of rice seedlings were studied using two rice cultivars （N07-6 and N07-63） differing in Cd tolerance. The contents of malondialdehyde （MDA）, reduce...The effect of H2O2 pretreatment on Cd tolerance and translocation of rice seedlings were studied using two rice cultivars （N07-6 and N07-63） differing in Cd tolerance. The contents of malondialdehyde （MDA）, reduced glutathione （GSH）, non-protein thiols （NPT）, phytochelatins （PCs） and the activity of glutathione S-transferase （GST） were compared between the two cultivars exposed to various treatments. The results showed that 50 μmol/L Cd exposure significantly inhibited rice growth, enhanced the production of GSH, NPT, PCs and MDA, and increased the activity of GST, and there were significant differences between the two cultivars. More Cd was transported into the shoot of N07-6. The H2O2 pretreatment alleviated Cd toxicity by further increasing GSH, NPT and PCs contents, as well as the GST activity in roots. The increase degrees of these parameters in N07-63 were higher than those in N07-6, suggesting that the tolerance of N07-63 was enhanced more significantly than N07-6. Hydrogen peroxide reduced Cd translocation to rice shoot but affected the Cd content in root differently. From the above results, it may be speculated that there were remarkable differences in the Cd detoxification and response to the H2O2 pretreatment between the two cultivars.展开更多
[ Objective] The FaOLtr2 （ Frago^ia ananassa osmotin-like protein） is a functional homolog of PR5-1ike protein. This study was undertaken to produce recombinant FaOLP2 and to identify its antifungal activity. [ Meth...[ Objective] The FaOLtr2 （ Frago^ia ananassa osmotin-like protein） is a functional homolog of PR5-1ike protein. This study was undertaken to produce recombinant FaOLP2 and to identify its antifungal activity. [ Method] The ORF of FaOLP2 （ accession number DQ325524） was cloned into pET22b vector to con- stroct the pET22b-FaOLP2 plasmid. The recombinant mature FaOLP2 was expressed in E. coli Rosetta-gami B （DE3） by inducing with I nunol/L IPTG and found exclusively in insoluble inclusion bodies. As FaOLP2 requires the correct formation of eight disulfide bonds, but there were no obvious effect to correctly form these by expression at different temperatures and high osmotic pressure （ supplemented Betaineand and D-Sorbitol）, we used an in vitro method to refold E. coli expressed FaOLP2 by gradually elution using reduced：oxidized gluthatione redox buffer, followed by 8 mol/L urea solubilized His6-tagged mature FaOLP2 protein, which was affinity-purified by an immobilized-metal （Ni2＋ ） affinity chromatography （IMAC） column. [ Result] This method generated biologically active conformations of the recombinant mature FaOLP2 that displayed antifungal activity against Ustilaginoides virens, a plant pathogenic fungus, which causes rice false smut. [ Conclusion] This study laid the foundation for further biotechnological application of the novel protein.展开更多
[ Objective] This study aimed to map quantitative tarit loci （QTLs） associated with salt tolerance of maize inbred line at seedling stage. [ Method! The recombinant inbred line （RIL） F7 including 171 plants were d...[ Objective] This study aimed to map quantitative tarit loci （QTLs） associated with salt tolerance of maize inbred line at seedling stage. [ Method! The recombinant inbred line （RIL） F7 including 171 plants were developed by single seed descent procedure from a combination, Huangzazsi × Mo17, and used to map QTLs associated with salt tolerance, based on the constructed genetic map of SSR markers. [ Resultl A linkage map consisting of 81 SSR markers loci from 10 chromosomes （ 1 428.3 cM in total length, with an average distance of 17.63 cM between two neighbouring loci） was constructed. Six QTI~ associated significantly with salt tolerance were detected at chromosomes 1,5 and 6. [ Conclusion] This study is extremely significant for better understanding sah tolerance-related genes, the genes＇ location and cloning, salt tolerance mechanism and the marker-assisted selection of salt tolerant maize.展开更多
In previous experiments, a natural late-flowering mutant was obtained from a late-season japonica rice line. The mutant exhibits no significant differences in various traits except growth period at the basic vegetativ...In previous experiments, a natural late-flowering mutant was obtained from a late-season japonica rice line. The mutant exhibits no significant differences in various traits except growth period at the basic vegetative growth stage compared with other wild-type varieties. In Jiaxing City, the heading stage of the late-flow- ering mutant was averagely delayed by about 20 days compared with other wild-type varieties. According to the results of progeny investigation and statistical analysis, the late-flowering mutant is controlled by a single recessive gene, which can be utilized with breeding technology to obtain sterile lines and multiple lines, thus expanding the germplasm resources for production application, which laid the foundation for subsequent studies.展开更多
Veterinary antibiotics can enter the environment due to the common practice of land application of manure from treated animals.The environmental fate of tetracyclines in swine manure after composting and field applica...Veterinary antibiotics can enter the environment due to the common practice of land application of manure from treated animals.The environmental fate of tetracyclines in swine manure after composting and field application remains largely unknown.This study analyzed the concentrations of tetracyclines in manure,manure-based compost and compost amended soil in selected swine farms from Beijing,Jiaxing and Putian,China to determine the dilution effects of antibiotics when released into the soil environment.The results demonstrate that residues of antibiotics were detected in all samples and chlortetracycline as well as its degradation products should be regarded critically concerning their potential ecotoxicity.Application of manure-based compost to soil could reduce the possible risk posed by antibiotic contamination,but the trigger value of 100 μg/kg was still exceeded in soil samples （776.1 μg/kg dw） from Putian City after application of compost.Field studies such as the present one can help to improve the routine administration of antibiotic-containing composted manure.展开更多
Mutation breeding is based on the induction of genetic variations; hence knowledge of the frequency and type of induced mutations is of paramount importance for the design and implementation of a mutation breeding pro...Mutation breeding is based on the induction of genetic variations; hence knowledge of the frequency and type of induced mutations is of paramount importance for the design and implementation of a mutation breeding program. Although γ ray irradiation has been widely used since the 1960 s in the breeding of about 200 economically important plant species, molecular elucidation of its genetic effects has so far been achieved largely by analysis of target genes or genomic regions. In the present study, the whole genomes of six γ-irradiated M2 rice plants were sequenced; a total of 144–188 million high-quality（Q〉20） reads were generated for each M2 plant, resulting in genome coverage of 45 times for each plant. Single base substitution（SBS） and short insertion/deletion（Indel） mutations were detected at the average frequency of 7.5×10^-6～9.8×10^-6 in the six M2 rice plants（SBS being about 4 times more frequent than Indels）. Structural and copy number variations, though less frequent than SBS and Indel, were also identified and validated. The mutations were scattered in all genomic regions across 12 rice chromosomes without apparent hotspots. The present study is the first genome-wide single-nucleotide resolution study on the feature and frequency of γ irradiation-induced mutations in a seed propagated crop; the findings are of practical importance for mutation breeding of rice and other crop species.展开更多
Targeting Induced Local Lesions IN Genomes （TILLING） is a reverse genetics strategy for the high-throughput screening of induced mutations.γ, radiation, which often induces both insertion/deletion （Indel） and poi...Targeting Induced Local Lesions IN Genomes （TILLING） is a reverse genetics strategy for the high-throughput screening of induced mutations.γ, radiation, which often induces both insertion/deletion （Indel） and point mutations, has been widely used in mutation induction and crop breeding. The present study aimed to develop a simple, high-throughput TILLING system for screening γ ray-induced mutations using high-resolution melting （HRM） analysis. Pooled rice （Oryza sativa） samples mixed at a 1：7 ratio of Indel mutant to wild-type DNA could be distinguished from the wild-type controls by HRM analysis. Thus, an HRM-TILLING system that analyzes pooled samples of four M2 plants is recommended for screening γ, ray-induced mutants in rice. For demonstration, a γ, ray-mutagenized M2 rice population （n=4560） was screened for mutations in two genes, OsLCT1 and SPDT, using this HRM-TILLING system. Mutations including one single nucleotide substitution （G→A） and one single nucleotide insertion （A） were identified in OsLCT1, and one tdnucleotide （TTC） deletion was identified in SPDT. These mutants can be used in rice breeding and genetic studies, and the findings are of importance for the application of γ, ray mutagenesis to the breeding of rice and other seed crops.展开更多
Grain shape is a key breeding target that influences both grain yield and appearance quality in rice. Breeding for long-slender grains is an effective strategy to improve grain quality (Jain et al., 2004;Wang et al., ...Grain shape is a key breeding target that influences both grain yield and appearance quality in rice. Breeding for long-slender grains is an effective strategy to improve grain quality (Jain et al., 2004;Wang et al., 2012, 2015a). In the past two decades, several quantitative trait loci (QTLs) responsible for grain size and shape have been identified, including GS3 (Fan et al., 2006), GS5 (Li et al., 2011).展开更多
The cytochrome P450 gene CYP81A6 confers tolerance to bentazon and metsulfuron-methyl, two selective herbicides widely used for weed control in rice and wheat fields. Knockout mutants of CYP81A6 are highly susceptible...The cytochrome P450 gene CYP81A6 confers tolerance to bentazon and metsulfuron-methyl, two selective herbicides widely used for weed control in rice and wheat fields. Knockout mutants of CYP81A6 are highly susceptible to both herbicides. The present study aimed to characterize the CYP81A6 expression in rice. Quantitative real-time polymerase chain reaction（PCR） analyses demonstrated that foliar treatment of bentazon（500 mg/L） greatly induced expression of CYP81A6 in both wild-type（Jiazhe B） and its knockout mutant（Jiazhe m B）： a 10-fold increase at 9 h before returning to basal levels at 24 h in Jiazhe B, while in the mutant the expression level rose to 20-fold at 12 h and maintained at such high level up to 24 h post exposure. In contrast, metsulfuron-methyl（500 mg/L） treatment did not affect the expression of CYP81A6 in Jiazhe B within 80 h; thereafter the expression peaked at 120 h and returned gradually to basal levels by Day 6. We suggest that a metabolite of metsulfuron-methyl, 1H-2,3-benzothiazin-4-（3H）-one-2,2-dioxide, is likely to be responsible for inducing CYP81A6 expression, rather than the metsulfuronmethyl itself. Use of a promoter-GUS reporter construct（CYP81A6Pro：：GUS） demonstrated that CYP81A6 was constitutively expressed throughout the plant, with the highest expression in the upper surfaces of leaves. Subcellular localization studies in rice protoplasts showed that CYP81A6 was localized in the endoplasmic reticulum. These observations advance our understanding of CYP81A6 expression in rice, particularly its response to the two herbicides.展开更多
Rice endosperm plays a very important role in seedling germination and determines the qualities of rice grain. Although studies on specific gene categories in endosperm have been carried out, global view of gene expre...Rice endosperm plays a very important role in seedling germination and determines the qualities of rice grain. Although studies on specific gene categories in endosperm have been carried out, global view of gene expression at a transcription level In rice endosperm Is still limited. To gain a better understanding of the global and tissue-specific gene expression profiles In rice endosperm, a cDNA library from rice endosperm of immature seeds was sequenced. A cDNA array was constructed based on the tentative unique transcripts derived from expression sequence tag （EST） assembling results and then hybridized with cDNAs from five different tissues or organs including endosperm, embryo, leaf, stem and root of rice. Significant redundancy was found for genes encoding prolamin, glutelin, allergen, and starch synthesis proteins, accounting for ~34% of the total ESTs obtained. The cDNA array revealed 87 significantly expressed genes In endosperm compared with the other four organs or tissues. These genes included 13 prolamin family proteins, 17 glutelin family proteins, 12 binding proteins, nine catalytic proteins and four ribosomal proteins, indicating a complicated biological processing in rice endosperm. In addition, Northern verification of 1,4-alpha-glucan branching enzyme detected two isoforms in rice endosperm, the larger one of which only existed in endosperm.展开更多
基金supported by the collaborative program of Chinese Academy of Agricultural Sciences(CAAS)-Jinhua Academy of Agricultural Sciences,funded by Jinhua City of Zhejiang Province,and the Research Grant fromWuhan Botanic Garden(E1559901)。
文摘Water caltrop(Trapa spp.,Lythraceae)is a traditional but currently underutilized non-cereal crop.Here,we generated chromosome-level genome assemblies for the two diploid progenitors of allotetraploid Trapa.natans(4x,AABB),i.e.,diploid T.natans(2x,AA)and Trapa incisa(2x,BB).In conjunction with four published(sub)genomes of Trapa,we used gene-based and graph-based pangenomic approaches and a pangenomic transposable element(TE)library to develop Trapa genomic resources.The pangenome displayed substantial gene-content variationwith dispensable and private gene clusters occupying a large proportion(51.95%)of the total cluster sets in the six(sub)genomes.Genotyping of presence-absence variation(PAVs)identified 40453 PAVs associated with 2570 genes specific to A-or B-lineages,of which 1428were differentially expressed,andwere enriched in organ development process,organic substancemetabolic process and response to stimulus.Comparative genome analyses showed that the allotetraploid T.natans underwent asymmetric subgenome divergence,with the B-subgenome being more dominant than the A-subgenome.Multiple factors,including PAVs,asymmetrical amplification of TEs,homeologous exchanges(HEs),and homeolog expression divergence,together affected genome evolution after polyploidization.Overall,this study sheds lights on the genome architecture and evolution of Trapa,and facilitates its functional genomic studies and breeding program.
基金supported by the Zhejiang Provincial S & T Project on Breeding of Agricultural (Food) Crops (Grant No. 2016C02050-2)
文摘To explore how rice(Oryza sativa L.) can be safely produced in Cd-polluted soil, OsLCT1 and OsNramp5 mutant lines were generated by CRISPR/Cas9-mediated mutagenesis. One of OsLCT1 mutant(lct1×1) and two of OsNramp5 mutants(nramp5×7 and nramp5×9) were evaluated for grain Cd accumulation and agronomic performances. In paddy field soil containing approximately 0.9 mg/kg Cd, lct1×1 grains contained approximately 40%(0.17 mg/kg) of the Cd concentration of the wild type parental line, less than the China National Food Safety Standard(0.20 mg/kg). Both OsNramp5 mutants showed low grain Cd accumulation(< 0.06 mg/kg) in the paddy(approximately 0.9 mg/kg Cd) or in pots in soil spiked with 2 mg/kg Cd. However, only nramp5×7 showed normal growth and yield, whereas the growth of nramp5×9 was severely impaired. The study showed that lct1×1 could be used to produce rice grains safe for human consumption in lightly contaminated paddy soils and nramp5×7 used in soils contaminated by much higher levels of Cd.
基金Project (No. 40432004) supported by the National Natural ScienceFoundation of China and the Science & Technology Foundation(2004) of Zhejiang Province, China
文摘A field demonstration of reduction of lead availability in a soil and cabbage (Brassica Chinensis L.) contaminated by mining tailings, located in Shaoxing, China was carried out to evaluate the effects of applications of phosphorus fertilizers on Pb fractionation and Pb phytoavailability in the soil. It was found that the addition of all three P fertilizers including single super phosphate (SSP), phosphate rock (PR), and calcium magnesium phosphate (CMP) significantly decreased the percentage of water-soluble and exchangeable (WE) soil Pb and then reduced the uptake of Pb, Cd, and Zn by the cabbage compared to the control (CK). The results showed that the level of 300 g P/m2 soil was the most cost-effective application rate of P fertilizers for reducing Pb availability at the first stage of remediation, and that at this P level, the effect of WE fraction of Pb in the soil de- creased by three phosphorus fertilizers followed the order: CMP (79%)>SSP (41%)>PR (23%); Effectiveness on the reduction of Pb uptake by cabbage was in the order: CMP (53%)>SSP (41%)>PR (30%). Therefore our field trial demonstrated that it was effective and feasible to reduce Pb availability in soil and cabbage contaminated by mining tailings using P fertilizers in China and PR would be a most cost-effective amendment.
基金financially supported by the National High-Tech R&D Program of China (863 Program,2007AA10Z220)National Key Technologies R&D Program during the 11th Five-Year Plan period of China(2006BAD17B06)+3 种基金the National Basic Research Program of China (973 Program, 2002CB111400)Zhejiang Provincial Key Project (2009CB119203)Zhejiang Yangtze Delta Key Sci & Tech Collaborative Program,China (2004E60055)Jiaxing City Key Sci & Tech Project, China (2005AZ3002)
文摘To understand the relationship between rice sowing date and occurrence of the rice small brown planthopper （SBPH） Laodelphax striatellus Fallen and the epidemics of the planthopper-transmitted rice stripe viral （RSV） disease, four sowing dates of rice were evaluated in 2006 and 2007. The results showed that the peak density of SBPH and RSV incidence in the nursery and in the transplanted field decreased with the delay of sowing date in single crop of japonica rice in north Zhejiang Province of China. The relationship between seedling RSV incidence at the end of the nursery trial with sowing date was well described by Weibull equation. The area under the curve of population dynamics （AUCPD or planthopper-day accumulation） or the peak density of the planthopper in the nursery could be summarized by a logistic equation. RSV incidence in the transplanted fields could be characterized quantitatively by a multivariate regression equation, including the variables of sowing date, peak density of the vector, and RSV incidence at the end of the nursery trial. That the descriptive model excluded the AUCPD in transplanted field implies that this variable is not necessary in forecasting disease epidemics in the field. The 2-year experiments sufficiently indicated that suitable sowing of rice could be used as one of the effective measures to control the vector population and therefore the planthopper-transmitted RSV on a larger scale. The optimal sowing date for the single-cropped transplanted japonica rice is recommended from late May to early June in north Zhejiang, China.
基金We are deeply grateful of the Postdoctoral Science Foundation of China(Grant No.2005037824)the Science and Technology Department of Zhejiang Province,China(Grant No.2005C32007)the Science and Technology Bureau of Jiaxing,Zhejiang,China (Grant No.2006AZ1008-1 and No.2008AZ2027)for financial support
文摘A pot experiment was conducted to study the effects of Cd on grain Cd, K, P, Mg, Zn, Cu, Pb, Fe and Mn accumulation in two rice genotypes （Xiushui 63 and Xiushui 217） differing in grain Cd accumulation under four Cd levels, i.e. 0, 0.5, 2.5 and 12.5 mg/kg. Rice genotype greatly affected the grain K content, but not significantly for P, Mg, Zn, Cu, Pb, Fe and Mn contents. There were remarkable effects of additional Cd on the contents of P, Mg and Zn in grains, while not significant for K, Cu, Pb, Fe and Mn contents. No significant differences were found in the interaction of genotype by additional Cd on these nine element contents. The low grain Cd accumulation genotype Xiushui 217 had significantly higher grain K, Mg, Cu and Mn contents than the high grain Cd accumulation genotype Xiushui 63, but the case was opposite for Zn, Pb and Fe contents. It also showed that Cd addition levels significantly influenced the K, P, Mg, Zn, Cu, Pb, Fe and Mn contents in rice grains. Grain K, P, Mg, Zn, Fe and Mn contents reduced with the increasing rate of Cd addition.
基金the financial support from the Natural Science Foundation of China (Grant No. 30700479)the Ph.D. Programs Foundation of Ministry of Education, China (Grant No. 20090097110035)
文摘The effect of H2O2 pretreatment on Cd tolerance and translocation of rice seedlings were studied using two rice cultivars （N07-6 and N07-63） differing in Cd tolerance. The contents of malondialdehyde （MDA）, reduced glutathione （GSH）, non-protein thiols （NPT）, phytochelatins （PCs） and the activity of glutathione S-transferase （GST） were compared between the two cultivars exposed to various treatments. The results showed that 50 μmol/L Cd exposure significantly inhibited rice growth, enhanced the production of GSH, NPT, PCs and MDA, and increased the activity of GST, and there were significant differences between the two cultivars. More Cd was transported into the shoot of N07-6. The H2O2 pretreatment alleviated Cd toxicity by further increasing GSH, NPT and PCs contents, as well as the GST activity in roots. The increase degrees of these parameters in N07-63 were higher than those in N07-6, suggesting that the tolerance of N07-63 was enhanced more significantly than N07-6. Hydrogen peroxide reduced Cd translocation to rice shoot but affected the Cd content in root differently. From the above results, it may be speculated that there were remarkable differences in the Cd detoxification and response to the H2O2 pretreatment between the two cultivars.
基金Supported by Zhejiang Province Natural Science Foundation(Y307591,Y3110288)Key Scientific and Technological Innovation Team Program of Zhejiang Province(2010R50028)
文摘[ Objective] The FaOLtr2 （ Frago^ia ananassa osmotin-like protein） is a functional homolog of PR5-1ike protein. This study was undertaken to produce recombinant FaOLP2 and to identify its antifungal activity. [ Method] The ORF of FaOLP2 （ accession number DQ325524） was cloned into pET22b vector to con- stroct the pET22b-FaOLP2 plasmid. The recombinant mature FaOLP2 was expressed in E. coli Rosetta-gami B （DE3） by inducing with I nunol/L IPTG and found exclusively in insoluble inclusion bodies. As FaOLP2 requires the correct formation of eight disulfide bonds, but there were no obvious effect to correctly form these by expression at different temperatures and high osmotic pressure （ supplemented Betaineand and D-Sorbitol）, we used an in vitro method to refold E. coli expressed FaOLP2 by gradually elution using reduced：oxidized gluthatione redox buffer, followed by 8 mol/L urea solubilized His6-tagged mature FaOLP2 protein, which was affinity-purified by an immobilized-metal （Ni2＋ ） affinity chromatography （IMAC） column. [ Result] This method generated biologically active conformations of the recombinant mature FaOLP2 that displayed antifungal activity against Ustilaginoides virens, a plant pathogenic fungus, which causes rice false smut. [ Conclusion] This study laid the foundation for further biotechnological application of the novel protein.
基金Supported by Project of Key Opening Laboratory of Physiology and Ecology of Crop in Cold Terra of Agriculture MinistryProject of the Department of Education of Heilongjiang Province (11521196)
文摘[ Objective] This study aimed to map quantitative tarit loci （QTLs） associated with salt tolerance of maize inbred line at seedling stage. [ Method! The recombinant inbred line （RIL） F7 including 171 plants were developed by single seed descent procedure from a combination, Huangzazsi × Mo17, and used to map QTLs associated with salt tolerance, based on the constructed genetic map of SSR markers. [ Resultl A linkage map consisting of 81 SSR markers loci from 10 chromosomes （ 1 428.3 cM in total length, with an average distance of 17.63 cM between two neighbouring loci） was constructed. Six QTI~ associated significantly with salt tolerance were detected at chromosomes 1,5 and 6. [ Conclusion] This study is extremely significant for better understanding sah tolerance-related genes, the genes＇ location and cloning, salt tolerance mechanism and the marker-assisted selection of salt tolerant maize.
基金Supported by Science and Technology Project of Jiaxing City(2010AZ2017,2012AY1053)Public Welfare Project of Zhejiang Province(2013C32028)
文摘In previous experiments, a natural late-flowering mutant was obtained from a late-season japonica rice line. The mutant exhibits no significant differences in various traits except growth period at the basic vegetative growth stage compared with other wild-type varieties. In Jiaxing City, the heading stage of the late-flow- ering mutant was averagely delayed by about 20 days compared with other wild-type varieties. According to the results of progeny investigation and statistical analysis, the late-flowering mutant is controlled by a single recessive gene, which can be utilized with breeding technology to obtain sterile lines and multiple lines, thus expanding the germplasm resources for production application, which laid the foundation for subsequent studies.
基金supported by the Major Projects of Knowledge Innovation Program of the Chinese Academy of Sciences (No. KZCX2-YW-Q02-05)the Beijing Science and Technology Program (No. D101105046410004)
文摘Veterinary antibiotics can enter the environment due to the common practice of land application of manure from treated animals.The environmental fate of tetracyclines in swine manure after composting and field application remains largely unknown.This study analyzed the concentrations of tetracyclines in manure,manure-based compost and compost amended soil in selected swine farms from Beijing,Jiaxing and Putian,China to determine the dilution effects of antibiotics when released into the soil environment.The results demonstrate that residues of antibiotics were detected in all samples and chlortetracycline as well as its degradation products should be regarded critically concerning their potential ecotoxicity.Application of manure-based compost to soil could reduce the possible risk posed by antibiotic contamination,but the trigger value of 100 μg/kg was still exceeded in soil samples （776.1 μg/kg dw） from Putian City after application of compost.Field studies such as the present one can help to improve the routine administration of antibiotic-containing composted manure.
基金supported by the National Natural Science Foundation of China(No.11275171)the National Key Technology R&D Program of China(No.2014BAA03B04)the Mutation Breeding Project of the Forum for Nuclear Cooperation in Asia(FNCA)
文摘Mutation breeding is based on the induction of genetic variations; hence knowledge of the frequency and type of induced mutations is of paramount importance for the design and implementation of a mutation breeding program. Although γ ray irradiation has been widely used since the 1960 s in the breeding of about 200 economically important plant species, molecular elucidation of its genetic effects has so far been achieved largely by analysis of target genes or genomic regions. In the present study, the whole genomes of six γ-irradiated M2 rice plants were sequenced; a total of 144–188 million high-quality（Q〉20） reads were generated for each M2 plant, resulting in genome coverage of 45 times for each plant. Single base substitution（SBS） and short insertion/deletion（Indel） mutations were detected at the average frequency of 7.5×10^-6～9.8×10^-6 in the six M2 rice plants（SBS being about 4 times more frequent than Indels）. Structural and copy number variations, though less frequent than SBS and Indel, were also identified and validated. The mutations were scattered in all genomic regions across 12 rice chromosomes without apparent hotspots. The present study is the first genome-wide single-nucleotide resolution study on the feature and frequency of γ irradiation-induced mutations in a seed propagated crop; the findings are of practical importance for mutation breeding of rice and other crop species.
基金Project supported by the National Key Research and Development Program of China(No.2016YFD0102103)
文摘Targeting Induced Local Lesions IN Genomes （TILLING） is a reverse genetics strategy for the high-throughput screening of induced mutations.γ, radiation, which often induces both insertion/deletion （Indel） and point mutations, has been widely used in mutation induction and crop breeding. The present study aimed to develop a simple, high-throughput TILLING system for screening γ ray-induced mutations using high-resolution melting （HRM） analysis. Pooled rice （Oryza sativa） samples mixed at a 1：7 ratio of Indel mutant to wild-type DNA could be distinguished from the wild-type controls by HRM analysis. Thus, an HRM-TILLING system that analyzes pooled samples of four M2 plants is recommended for screening γ, ray-induced mutants in rice. For demonstration, a γ, ray-mutagenized M2 rice population （n=4560） was screened for mutations in two genes, OsLCT1 and SPDT, using this HRM-TILLING system. Mutations including one single nucleotide substitution （G→A） and one single nucleotide insertion （A） were identified in OsLCT1, and one tdnucleotide （TTC） deletion was identified in SPDT. These mutants can be used in rice breeding and genetic studies, and the findings are of importance for the application of γ, ray mutagenesis to the breeding of rice and other seed crops.
基金supported by grants from the National Natural Science Foundation of China,China(31970304,31971916)Youth Innovation Promotion Association,Chinese Academy of Sciences (2019-100),ChinaOpen Fund of the Guangdong Key Laboratory of Plant Molecular Breeding(GPKLPMB201904)
文摘Grain shape is a key breeding target that influences both grain yield and appearance quality in rice. Breeding for long-slender grains is an effective strategy to improve grain quality (Jain et al., 2004;Wang et al., 2012, 2015a). In the past two decades, several quantitative trait loci (QTLs) responsible for grain size and shape have been identified, including GS3 (Fan et al., 2006), GS5 (Li et al., 2011).
基金supported by the Ministry of Science and Technology of China(No.BAA03B04)the Fundamental Research Funds for the Central Universities of China
文摘The cytochrome P450 gene CYP81A6 confers tolerance to bentazon and metsulfuron-methyl, two selective herbicides widely used for weed control in rice and wheat fields. Knockout mutants of CYP81A6 are highly susceptible to both herbicides. The present study aimed to characterize the CYP81A6 expression in rice. Quantitative real-time polymerase chain reaction（PCR） analyses demonstrated that foliar treatment of bentazon（500 mg/L） greatly induced expression of CYP81A6 in both wild-type（Jiazhe B） and its knockout mutant（Jiazhe m B）： a 10-fold increase at 9 h before returning to basal levels at 24 h in Jiazhe B, while in the mutant the expression level rose to 20-fold at 12 h and maintained at such high level up to 24 h post exposure. In contrast, metsulfuron-methyl（500 mg/L） treatment did not affect the expression of CYP81A6 in Jiazhe B within 80 h; thereafter the expression peaked at 120 h and returned gradually to basal levels by Day 6. We suggest that a metabolite of metsulfuron-methyl, 1H-2,3-benzothiazin-4-（3H）-one-2,2-dioxide, is likely to be responsible for inducing CYP81A6 expression, rather than the metsulfuronmethyl itself. Use of a promoter-GUS reporter construct（CYP81A6Pro：：GUS） demonstrated that CYP81A6 was constitutively expressed throughout the plant, with the highest expression in the upper surfaces of leaves. Subcellular localization studies in rice protoplasts showed that CYP81A6 was localized in the endoplasmic reticulum. These observations advance our understanding of CYP81A6 expression in rice, particularly its response to the two herbicides.
基金the Zhejiang Provincial Science and Technology Project(2005C22002)
文摘Rice endosperm plays a very important role in seedling germination and determines the qualities of rice grain. Although studies on specific gene categories in endosperm have been carried out, global view of gene expression at a transcription level In rice endosperm Is still limited. To gain a better understanding of the global and tissue-specific gene expression profiles In rice endosperm, a cDNA library from rice endosperm of immature seeds was sequenced. A cDNA array was constructed based on the tentative unique transcripts derived from expression sequence tag （EST） assembling results and then hybridized with cDNAs from five different tissues or organs including endosperm, embryo, leaf, stem and root of rice. Significant redundancy was found for genes encoding prolamin, glutelin, allergen, and starch synthesis proteins, accounting for ~34% of the total ESTs obtained. The cDNA array revealed 87 significantly expressed genes In endosperm compared with the other four organs or tissues. These genes included 13 prolamin family proteins, 17 glutelin family proteins, 12 binding proteins, nine catalytic proteins and four ribosomal proteins, indicating a complicated biological processing in rice endosperm. In addition, Northern verification of 1,4-alpha-glucan branching enzyme detected two isoforms in rice endosperm, the larger one of which only existed in endosperm.
