In a genome-wide association study,we identified a rice UDP-glycosyltransferase gene,OsUGT706D2,whose transcription was activated in response to cold and submergence stress and to exogenous abscisic acid(ABA).OsUGT706...In a genome-wide association study,we identified a rice UDP-glycosyltransferase gene,OsUGT706D2,whose transcription was activated in response to cold and submergence stress and to exogenous abscisic acid(ABA).OsUGT706D2 positively regulated the biosynthesis of tricin-4’-O-(syringyl alcohol)ether-7-O-glucoside at both the transcriptional and metabolic levels.OsUGT706D2 mediated cold and submergence tolerance by modulating the expression of stress-responsive genes as well as the abscisic acid(ABA)signaling pathway.Gain of function of OsUGT706D2 increased cold and submergence tolerance and loss of function of OsUGT706D2 reduced cold tolerance.ABA positively regulated OsUGT706D2-mediated cold tolerance but reduced submergence tolerance.These findings suggest the potential use of OsUGT706D2 for improving abiotic stress tolerance in rice.展开更多
Scour around a submerged square pile was realized experimentally in a steady flow to study the effects of flow depth on local scour.Flow depth to pile height ratios ranging from 1.5 to 5 in uniform sand and 2 to 5 in ...Scour around a submerged square pile was realized experimentally in a steady flow to study the effects of flow depth on local scour.Flow depth to pile height ratios ranging from 1.5 to 5 in uniform sand and 2 to 5 in non-uniform sand were tested in the approaching flow velocity to critical velocity(larger than which the sediment particle is motivated)ratios of 0.56 and 1.03,respectively.The influences of flow depth were investigated on the basis of analysis of the three-dimensional topography,temporal maximum scour depth,bed profile development,and equilibrium scour depth.Results showed that the maximum scour depth was at the upstream corners of the pile other than at the stagnation point.The evolutions of the maximum scour depth data in non-uniform sand were well fitted with a recent exponential function,which characterized the initial,developing,and equilibrium stages of scour depth.The scour hole slopes upstream of the pile were found to be parallel to each other in the process of each test and were mainly governed by the sediment repose underwater.The equilibrium scour depth varied slightly with flow depth when the submergence ratio was larger than 1 in uniform sand while it was 2 in non-uniform sand.The armoring effects of coarse sediment particles markedly reduced the sediment transport in non-uniform sand despite the 0.34 increment in non-uniformity.展开更多
To investigate the expression profile of maize genes induced by submergence, a subtracted cDNA library of maize seedling roots was constructed using suppression subtractive hybridization (SSH). The cDNA of maize seedl...To investigate the expression profile of maize genes induced by submergence, a subtracted cDNA library of maize seedling roots was constructed using suppression subtractive hybridization (SSH). The cDNA of maize seedling roots treated with submergence (ST) was used as tester and what from untreated roots (UT) as driver. Products of the secondary PCR from the forward subtraction were cloned into T/A vector and transferred into Escherichia coli strain JM10B by electroporation. Four hundred and eight randomly chosen transformants carrying cDNA fragments were screened with PCR-Select Deferential Screening Kit. One hundred and eighty-four cDNA clones were identified as, submergence specifically induced or highly expressed. After sequencing and removing redundant cDNAs, we got 95 submergence-induced cDNA clones. Of the 95 cDNA clones, 68 contain the regions with 60%-90% identity to their homolog in GenBank, 21 are expected to be novel genes, only 6 correspond to the published maize sequences.展开更多
Flooding/submergence of rice fields is a severe problem in South and South-East Asia, affecting more than 20 million hectares of rice every year. Submergence creates hypoxic or anoxic condition causing poor germinatio...Flooding/submergence of rice fields is a severe problem in South and South-East Asia, affecting more than 20 million hectares of rice every year. Submergence creates hypoxic or anoxic condition causing poor germination, seedling establishment,and enormous yield loss. Standing water in the field from weeks to months also leads to significant yield losses when large part of aerial tissues is under water. For flash flooding, a rice variety FR1A3 with tolerant gene(SUB1A) was identified. SNORKEL1 and SNORKEL2 have been identified for their ability to survive deep-water flooding by rapid elongation. Submergence stress has also been reported to adversely affect cell division and damage cellular and organelle membranes. Research on antioxidative enzymes response and genes that confer tolerance to prolonged flooding is in progress. Here we review the different anoxia responsive genes and the potential involvement of antioxidative enzymes, such as superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase, which occur in cells of rice plant exposed to submergence stress.展开更多
The influence of submergence on photosynthesis and antioxidant capacities in rice varieties Swarna and Swarna-Subl with or without Sub1 QTL were evaluated under control, simulated complete submergence and subsequent r...The influence of submergence on photosynthesis and antioxidant capacities in rice varieties Swarna and Swarna-Subl with or without Sub1 QTL were evaluated under control, simulated complete submergence and subsequent re-aeration. The leaf photosynthetic rate and stomatal conductance decreased in the both varieties during the progression of submergence as compared to the control plants, but significant varietal differences were observed after 1 d of submergence. Submergence also altered the PSII activity, as reflected in a decrease in the values of Fo, Fm and Fv/Fm and degradation of chlorophyll, more in Swarna than in Swarna-Subl. During early submergence period, the activities of superoxide dismutase （SOD）, ascorbate peroxidase （APX）, dehydroascorbate reductase （DHAR）, glutathione reductase （GR） against reactive oxygen species were increased in the both varieties. However, with the progress of submergence period （after 7 d）, the activities of SOD, catalase （CAT）, APX, guaiacol peroxidase （GPX）, GR and DHAR declined, more in Swarna than in Swarna-Subl. During re-aeration, Swarna-Subl showed significant increase of above antioxidant enzymes but not in Swarna, Swarna-Subl improves photosynthetic activity, showing higher photosynthetic rate compared to Swarna under submergence and subsequent re-aeration because of less degradation of chlorophyll, higher stomatal conductance, and efficient PSII activity along with better antioxidant protection from oxidative damage.展开更多
One sequence tagged site marker Subl-1 and twice submergence stress method were used in selection of submergence tolerant homozygous line from Sub-lBS, a submergence tolerant, bentazon sensitive and photoperiod-sensit...One sequence tagged site marker Subl-1 and twice submergence stress method were used in selection of submergence tolerant homozygous line from Sub-lBS, a submergence tolerant, bentazon sensitive and photoperiod-sensitive and/or thermo-sensitive genic male sterile line that developed by our laboratory. The results revealed that the original Sub-lBS was heterozygous in SublA-1 locus even though it was identical in almost all of agronomical traits and the segregation of SublA-1 was in accordance with Mendelian law based on chi-square test. And then the original Sub-IBS was divided into two groups： one was ofSublA-1 introgression and the other was not; and the two groups were tested by twice submergence stress method. After the first submergence stress that lasted for 12 d, the average plant heights were significant difference at the 1% level between the two groups. After recovery for 10 d, the second submergence stress sustained for 18 d was carried on; and the group with SublA-1 gene was found apparently tolerant than the other group in submergence tolerance.展开更多
Submergence is a serious environmental condition that causes large loss in rice production in rain fed lowland and flood affected area. This study evaluated morphological and physiological responses of rice roots to s...Submergence is a serious environmental condition that causes large loss in rice production in rain fed lowland and flood affected area. This study evaluated morphological and physiological responses of rice roots to submergence using two tolerant rice genotypes FR13A and Swarna-Sub 1 and two sensitive ones Swarna and IR42. The tolerant genotypes had higher survival rate and less shoot elongation but greater root elongation during submergence than the sensitive ones. After submergence,the tolerant genotypes also had higher root dry weight and more active roots than the sensitive ones.Tolerant genotypes exhibited less root injury, with less malondialdehyde production and slower electrolyte leakage after submergence. Tolerant genotypes also maintained higher concentrations of soluble sugar and starch in roots and shoots and higher chlorophyll retention after submergence than the sensitive ones.Our data showed that root traits such as root activity and root growth are associated with survival rate after submergence. This is probably accomplished through higher energy supply, and membrane integrity is necessary to preserve root function and reduce injury during submergence. These root traits are important for submergence tolerance in rice.展开更多
Ethylene response factor proteins play an important role in regulating a variety of stress responses in plants,but their exact functions in submergence stress are not well understood.In this study,we isolated BnE RF2....Ethylene response factor proteins play an important role in regulating a variety of stress responses in plants,but their exact functions in submergence stress are not well understood.In this study,we isolated BnE RF2.4 from Brassica napus L.to study its function in submergence tolerance.The expression of the BnE RF2.4 gene in B.napus and the expression of antioxidant enzyme genes in transgenic Arabidopsis were analyzed by quantitative RT-PCR.The expression of BnE RF2.4 was induced by submergence in B.napus and the overexpression of BnE RF2.4 in Arabidopsis increased the level of tolerance to submergence and oxidative stress.A histochemical method detected lower levels of H_2O_2,O^(·-)_2and malondialdehyde(MDA) in transgenic Arabidopsis.Compared to the wild type,transgenic lines also had higher soluble sugar content and higher activity of antioxidant enzymes,which helped to protect plants against the oxidative damage caused by submergence.It was concluded that BnE RF2.4 increased the tolerance of plants to submergence stress and may be involved in regulating soluble sugar content and the antioxidant system in defense against submergence stress.展开更多
Two variable charge soils were submerged after the addition of 30g/kg of organic matter to examine the differences in behavior between iron and manganese with respect to reduction and the distribution of different for...Two variable charge soils were submerged after the addition of 30g/kg of organic matter to examine the differences in behavior between iron and manganese with respect to reduction and the distribution of different forms of the reduced elements. The reduction of manganese proceeded almost synchronously with the fall in redox potential, while the reduction of iron showed a remarkable lag behind the Eh change. Once formed,the distribution of water-soluble, exchangeable and precipitated forms of ferrous iron was controlled by PH,CEC of the soil and total concentration of the element. For manganous ions, the proportions of water-soluble and exchangeable forms in total Mn(2+) were larger than those for ferrous ions. The reduction of the two elements led to a mobilization of them, and such effect persisted even after drying of the soil, i.e.,the content of amorphous Fe became higher than that of the original soil.展开更多
Rice line 1892S is an elite thermo-sensitive genic male sterile(TGMS)line for two-line hybrid rice production.However,1892S is susceptible to rice blast,bacterial blight and submergence.Here we reported the introducti...Rice line 1892S is an elite thermo-sensitive genic male sterile(TGMS)line for two-line hybrid rice production.However,1892S is susceptible to rice blast,bacterial blight and submergence.Here we reported the introduction of blast resistance(R)gene Pi9,bacterial blight R gene Xa21 and submergence tolerance gene Sub1A into 1892S genetic background through backcrossing and marker-assisted selection.The improved TGMS line 31892S and its hybrids conferred disease resistance to rice blast and bacterial blight,and showed submergence tolerance for over 14 d without significant loss of viability.The sterility-fertility conversion of 31892S was similar to that of 1892S.31892S and its derived hybrid rice had similar agronomic traits and grain quality with 1892S and the control hybrid rice,respectively.The newly developed 31892S provided an improved TGMS line for two-line hybrid rice production with disease resistance to rice blast and bacterial blight,and submergence tolerance with no yield penalty or change in grain quality.展开更多
The present study evaluated submergence responses in 88 lowland indigenous rice(Oryza sativa L.) landraces from Koraput, India, to identify submergence-tolerant rice genotypes. In pot experiments, variations in surviv...The present study evaluated submergence responses in 88 lowland indigenous rice(Oryza sativa L.) landraces from Koraput, India, to identify submergence-tolerant rice genotypes. In pot experiments, variations in survival rate, shoot elongation, relative growth index, dry matter, chlorophyll, soluble sugar and starch contents were evaluated in two consecutive years under well-drained and completely submerged conditions. Principal component analysis showed that the first three axes contributed 96.820% of the total variation among the landraces, indicating wide variation between genotypes. Major traits such as survival rate, relative growth index, soluble sugar and starch contents appeared to be important determinants of phenotypic diversity among the landraces. Phenotypic coefficient of variance was higher than genotypic coefficient of variance for all the traits and all showed high heritability(90.38%–99.54%). Five rice landraces(Samudrabali, Basnamundi, Gadaba, Surudaka and Dokarakuji) were the most tolerant to submergence. When submerged for up to 14d, Samudrabali, Basnamundi and Godoba were notable for having greater survival rates than a standard submergence tolerant variety FR13 A, and also notable for elongating more vigorously and accumulating more biomass. These three landraces may therefore be especially useful in lowland rice growing areas that are affected by both moderate stagnant water and flash flooding. Molecular genotyping revealed that the submergence tolerance of Samudrabali, Basnamundi and Godoba is linked to the presence of one or more different Sub1 loci and it may well prove useful for breeding improved submergence tolerant rice varieties, thereby assising to improve yield stability in the rainfed lowland agro-ecosystem.展开更多
In the present study a group of four indigenous and less popular rice genotypes (Meghi, Panibhasha, Jabra and Sholey) reported by growers as submergence tolerant lines from flood prone areas of south Bengal were explo...In the present study a group of four indigenous and less popular rice genotypes (Meghi, Panibhasha, Jabra and Sholey) reported by growers as submergence tolerant lines from flood prone areas of south Bengal were explored through study of nodal anatomy, physio-biochemical screening under submergence and genotyping with submergence tolerance linked rice microsatellite loci (RM loci). To identify the different allelic forms of different Sub1 compnents (Sub1A, Sub1B and Sub1C) among the studied lines, the genomic DNA of individual genotypes was amplified with three ethylene response factor like genes from Sub1 loci, located on rice chromosome 9. From the different physio-biochemical experiments performed in this investigation, it has been shown that Meghi and Jabra are the two probable potent genotypes which share common properties of both submergence tolerant and deep water nature whereas rest two genotypes (Sholey and Panibhasha) behave like typical deep water rice. The submergence tolerance property of Meghi was also confirmed from submergence tolerance linked SSR based genotyping by sharing with FR13A for some common alleles as reflected in fingerprint derived dendrogram. The rest of the genotypes shared a number of alleles and were included in a separate cluster. The common behaviour of Meghi and FR13A under submergence was also confirmed from genetic study of Sub1 loci through sharing of some common alleles for three Sub1 components (Sub1A, Sub1B and Sub1C loci). One SSR loci (RM 285) was identified as a potent molecular marker for submergence tolerance breeding programme involving these two selected rice lines (Meghi and Jabra) as donor plant through marker assisted selection.展开更多
Three rice varieties, significantly differed in their ability, when subjected to submergence have been studied in relation to physiological attributes. On account of oxidative stress, MDA content and carbonyl content ...Three rice varieties, significantly differed in their ability, when subjected to submergence have been studied in relation to physiological attributes. On account of oxidative stress, MDA content and carbonyl content were measured. The MDA content was maximally decreased in FR13A and minimally decreased in Swarna irrespective of shoots and roots. A higher increase in carbonyl content was found in Swarna followed by FR13A and Swarna Sub1A in both shoots and roots. The activity of antioxidant moieties like total phenolics content and flavonoid content were more increased under submergence than that in air except for Swarna. FR13A showed maximum increase in Phenolics and flavonoid content in both shoots and roots when subjected to submergence. A sharp increase in guaiacol peroxidase and glutathione reductase characterized the plants’ response to sub-mergence irrespective of varieties. The expression of Guaiacol peroxidase was increased in FR13A followed by Swarna Sub1A and Swarna. Glutathione reductase was measured in terms of oxidation of NADP(H) and both FR13A and Swarna Sub1A recorded maximum oxidation than Swarna under submergence. With regards to isozymic variation plants were differed to the intensities of poly-peptide, however not in numbers and may be suggestive for concomitant gene expression to sub-mergence. The analysis clarification for possible biomarkers with regards to cellular responses of rice plants under submergence has been anticipated.展开更多
Flash flood or submergence is a common phenomenon in rice growing rainfed lowland areas that seriously affects crop establishment leading to severe yield losses. A few submergence-tolerant rice varieties have been dev...Flash flood or submergence is a common phenomenon in rice growing rainfed lowland areas that seriously affects crop establishment leading to severe yield losses. A few submergence-tolerant rice varieties have been developed by introgressing SUB1 gene into mega rice varieties of South Asia. Two of these, Swarna-Sub1 and Sambha Mahsuri-Sub1, are already released in India for the commercial cultivation. Performance of these varieties can be further enhanced through adoption of appropriate management practices both in nursery and in main field. Two on-station field experiments were conducted using Swarna-Sub1 during the wet season (kharif) of 2011 at Rice Research Station, Chinsurah, Hooghly, West Bengal (India). Results of these experiments revealed that the use of lower seeding density (25 g m-2), application of balanced doses of N-P2O5-K2O @ 80-40-40 kg ha-1 in nursery and transplanting of aged seedlings (44 days) significantly improved plant survival, yield attributing traits and grain yield. An additional N-dose of 20 kg ha-1 at 7 days after receding of flood water resulted in better post-submergence recovery and maximum grain yield. In the on-farm trials conducted at three different locations in West Bengal, nursery raising of seedlings with the application of N-P2O5-K2O @ 80-40-40 kg ha-1, transplanting them at an optimum age (35 days) and application of 20 kg·N ha-1 after 7 days of de-submergence produced maximum grain yield of Swarna-Sub1.展开更多
The composition of membrane lipids is sensitive to environmental stresses.Submergence is a type of stress often encountered by plants.However,how the molecular species of membrane lipids respond to submergence has not...The composition of membrane lipids is sensitive to environmental stresses.Submergence is a type of stress often encountered by plants.However,how the molecular species of membrane lipids respond to submergence has not yet been characterised.In this study,we used a lipidomic approach to profile the molecular species of membrane lipids in whole plants of Arabidopsis thaliana that were completely submerged for three days.The plants survived one day of submergence,after which,we found that the total membrane lipids were only subtly decreased,showing significant decreases of monogalactosyldiacylglycerol(MGDG)and phosphatidylcholine(PC)and an increase of phosphatidic acid(PA);however,the basic lipid composition was retained.In contrast,three days of submergence caused plants to die,and the membranes deteriorated via the rapid loss of 96% of lipid content together with a 229% increase in PA.The turnover of molecular species from PG and MGDG to PA indicated that submergenceinduced lipid changes occurred through PA-mediated degradation.In addition,molecular species of extraplastidic PG degraded sooner than plastidic ones,lyso-phospholipids exhibited various patterns of change,and the double-bond index(DBI)remained unchanged until membrane deterioration.Our results revealed the unique changes of membrane lipids upon submergence and suggested that the major cause of the massive lipid degradation could be anoxia.展开更多
The detrimental effects of submergence on physiological performances of some rice varieties with special references to carbohydrate metabolisms and their allied enzymes during post-flowering stages have been documente...The detrimental effects of submergence on physiological performances of some rice varieties with special references to carbohydrate metabolisms and their allied enzymes during post-flowering stages have been documented and clarified in the present investigation. It was found that photosynthetic rate and concomitant translocation of sugars into the panicles were both related to the yield. The detrimental effects of the complete submergence were recorded in generation of sucrose, starch, sucrose phosphate synthase and phosphorylase activity in the developing panicles of the plants as compared to those under normal or control （i.e. non-submerged） condition. The accumulation of starch was significantly lower in plants under submergence and that was correlated with ADP-glucose pyrophosphorylase activity. Photosynthetic rate was most affected under submergence in varying days of post-flowering and was also related to the down regulation of Ribulose bisphosphate carboxylase activity. However, under normal or control condition, there recorded a steady maintenance of photosynthetic rate at the post-flowering stages and significantly higher values of Ribulose bisphosphate carboxylase activity. Still, photosynthetic rate of the plants under both control and submerged conditions had hardly any significant correlation with sugar accumulation and other enzymes of carbohydrate metabolism like invertase with grain yield. Finally, plants under submergence suffered significant loss of yield by poor grain filling which was related to impeded carbohydrate metabolism in the tissues. It is evident that loss of yield under submergence is attributed both by lower sink size or sink capacity （number of panicles, in this case） as well as subdued carbohydrate metabolism in plants and its subsequent partitioning into the grains.展开更多
A thermostatic incubation experiment was carried out to estimate the effects of flooding periods, stalk application and P addition on Fe transformation and P availability in calcareous soils. Submergence increased amo...A thermostatic incubation experiment was carried out to estimate the effects of flooding periods, stalk application and P addition on Fe transformation and P availability in calcareous soils. Submergence increased amorphous Fe, especially in the case of stalk application. The newly formed amorphous Fe with a great surface area played an important role in P sorption; and submergence also stimulated the dissolution of inorganic P, thus increasing the availability of soil P in calcareous soils. Meanwhile, a part of soluble P was adsorbed and fixed again on the surface of newly formed amorphous Fe, thus resulting in a decrease of P availability. Soil rapidly available P increased after ISO-day incubation. There existed significantly negative correlations between soil amorphous Fe content and soil Fe-P and rapidly available P contents. Submerged conditions promoted the transformation of inorganic P added to-ward Fe-P in calcareous soils, especially in the case of stalk application.展开更多
Submergence tolerant high yielding rice variety was developed using BR11 as a recipient parent applying foreground, phenotypic and background selection approaches. Recombinant selection was found essential to minimize...Submergence tolerant high yielding rice variety was developed using BR11 as a recipient parent applying foreground, phenotypic and background selection approaches. Recombinant selection was found essential to minimize linkage drag by BC2F2 generation. Without recombinant selection, the introgression size in the backcross recombinant lines （BRLs） was approximately 15 Mb on the carrier chromosome. The BRLs were found submergence tolerance compared to the check varieties under complete submergence for two weeks at Bangladesh Rice Research Institute, and produced higher yield compared to the isogenic Subl-line under controlled submerged condition. The BRL IR85260-66-654-Gaz2 was released as BRRI dhan52 in 2010, which was the first high yielding submergence tolerant variety in Bangladesh. BRRI dhan52 produced grain yield ranging from 4.2 to 5.2 t/hm2 under different flash flood prone areas of Bangladesh in three consecutive seasons. The study demonstrated the efficiency of recombinant selection and better adaptability of the newly released submergence tolerant high yielding variety in flash flood prone different areas of the country with respect to submergence tolerance and yield potential.展开更多
In this paper, the influence depths of all levels of wind power produced waves are reckoned according to the measured swaying degree when a submarine meets with a force 11 strong tropical storm and has to submerge; Th...In this paper, the influence depths of all levels of wind power produced waves are reckoned according to the measured swaying degree when a submarine meets with a force 11 strong tropical storm and has to submerge; Then the minimum submergence depth is given when a submarine is faced with weather systems with force ≥ 6 wind and the swaying degree of less than 12 degree is assured as reference for a submarine working and sailing in big strong winds and waves.展开更多
The result of the study contributes to enhancing and sustaining future livelihoods and food security in Vietnam vis-a-vis climate change. An innovative strategy based on marker-assisted backcrossing (MABC) was used to...The result of the study contributes to enhancing and sustaining future livelihoods and food security in Vietnam vis-a-vis climate change. An innovative strategy based on marker-assisted backcrossing (MABC) was used to transform popular rice variety AS996 into the one can tolerate submergence while maintaining its original characteristics preferred by farmers and consumers. The submergence tolerance QTL SUB1 counts for up to 70% of the submergence tolerant and provides a marked improvement of submergence tolerance in all genetic backgrounds and environments tested so far. Parental diversity was carried out with 460 markers. Of which, 53 polymorphic markers were used for assessment on BC1F1, BC2F1 and BC3F1 generations. The best BC1F1 plant was P422 with highest recipient allele was 87.5%, while the additional chosen plants were P412, P428, P215 and P39 (81% - 84%). All these plants were used to develop BC2F1 generation. The six BC2F1 plants were used to develop BC3F1 and BC2F2 were the plants number P422-11 and P422-14 having 93.75% recipient alleles and P422-12, P422-3, P39-17, P39-25 having 92.25% recipient alleles. Total of 445 BC3F1 plants were confirmed the introgresion of SUB1 using ART5 and SC3. After three generations of backcrossing, application of MABC resulted in the best BC3F1 individual P422-14-177 with 100% of recipient alleles based on the number of 53 markers used with only the introgression size of SUB1 was 0.3Mb between ART5 and SC3. Phenotyping was carried out on BC3F1 and BC2F2 of the selected lines. The survival ratio of these selected lines and IR64SUB1 were the same. It convinced the successfully introgress SUB1 into AS996 rice variety. The breeding line BC4F1 having 100% genetic background of donor variety is ready for develop new submergence tolerant rice variety ASS996-SUB1 to cope with climate change.展开更多
基金jointly funded by National Natural Science Foundation of China(32372206)the Natural Science Foundation of Guangdong Province(2023A1515030224,2023A0505090005,2021TQ06N115)+3 种基金the Governor’s Special Program of 2023(Yuecainong[2023]No.145)the Key Field Research and Development Project of Guangdong Province(2022B0202110003)the Special Fund for Scientific Innovation Strategy-Construction of High Level Academy of Agriculture Science(R2020PY-JX001)Guangdong Key Laboratory of New Technology in Rice Breeding(2023B1212060042)。
文摘In a genome-wide association study,we identified a rice UDP-glycosyltransferase gene,OsUGT706D2,whose transcription was activated in response to cold and submergence stress and to exogenous abscisic acid(ABA).OsUGT706D2 positively regulated the biosynthesis of tricin-4’-O-(syringyl alcohol)ether-7-O-glucoside at both the transcriptional and metabolic levels.OsUGT706D2 mediated cold and submergence tolerance by modulating the expression of stress-responsive genes as well as the abscisic acid(ABA)signaling pathway.Gain of function of OsUGT706D2 increased cold and submergence tolerance and loss of function of OsUGT706D2 reduced cold tolerance.ABA positively regulated OsUGT706D2-mediated cold tolerance but reduced submergence tolerance.These findings suggest the potential use of OsUGT706D2 for improving abiotic stress tolerance in rice.
基金the support of the National Natural Science Foundation of China(Nos.51679223 and 51739010)the 111 Project(No.B14028),the Shangdong Provincial Key Laboratory of Ocean Engineering(No.kl oe202009)+1 种基金the Ningbo Natural Science Foundation(No.2021J096)a grant from the 7th Generation Ultra-Deepwater Drilling Rig Innovation Project。
文摘Scour around a submerged square pile was realized experimentally in a steady flow to study the effects of flow depth on local scour.Flow depth to pile height ratios ranging from 1.5 to 5 in uniform sand and 2 to 5 in non-uniform sand were tested in the approaching flow velocity to critical velocity(larger than which the sediment particle is motivated)ratios of 0.56 and 1.03,respectively.The influences of flow depth were investigated on the basis of analysis of the three-dimensional topography,temporal maximum scour depth,bed profile development,and equilibrium scour depth.Results showed that the maximum scour depth was at the upstream corners of the pile other than at the stagnation point.The evolutions of the maximum scour depth data in non-uniform sand were well fitted with a recent exponential function,which characterized the initial,developing,and equilibrium stages of scour depth.The scour hole slopes upstream of the pile were found to be parallel to each other in the process of each test and were mainly governed by the sediment repose underwater.The equilibrium scour depth varied slightly with flow depth when the submergence ratio was larger than 1 in uniform sand while it was 2 in non-uniform sand.The armoring effects of coarse sediment particles markedly reduced the sediment transport in non-uniform sand despite the 0.34 increment in non-uniformity.
文摘To investigate the expression profile of maize genes induced by submergence, a subtracted cDNA library of maize seedling roots was constructed using suppression subtractive hybridization (SSH). The cDNA of maize seedling roots treated with submergence (ST) was used as tester and what from untreated roots (UT) as driver. Products of the secondary PCR from the forward subtraction were cloned into T/A vector and transferred into Escherichia coli strain JM10B by electroporation. Four hundred and eight randomly chosen transformants carrying cDNA fragments were screened with PCR-Select Deferential Screening Kit. One hundred and eighty-four cDNA clones were identified as, submergence specifically induced or highly expressed. After sequencing and removing redundant cDNAs, we got 95 submergence-induced cDNA clones. Of the 95 cDNA clones, 68 contain the regions with 60%-90% identity to their homolog in GenBank, 21 are expected to be novel genes, only 6 correspond to the published maize sequences.
文摘Flooding/submergence of rice fields is a severe problem in South and South-East Asia, affecting more than 20 million hectares of rice every year. Submergence creates hypoxic or anoxic condition causing poor germination, seedling establishment,and enormous yield loss. Standing water in the field from weeks to months also leads to significant yield losses when large part of aerial tissues is under water. For flash flooding, a rice variety FR1A3 with tolerant gene(SUB1A) was identified. SNORKEL1 and SNORKEL2 have been identified for their ability to survive deep-water flooding by rapid elongation. Submergence stress has also been reported to adversely affect cell division and damage cellular and organelle membranes. Research on antioxidative enzymes response and genes that confer tolerance to prolonged flooding is in progress. Here we review the different anoxia responsive genes and the potential involvement of antioxidative enzymes, such as superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase, which occur in cells of rice plant exposed to submergence stress.
文摘The influence of submergence on photosynthesis and antioxidant capacities in rice varieties Swarna and Swarna-Subl with or without Sub1 QTL were evaluated under control, simulated complete submergence and subsequent re-aeration. The leaf photosynthetic rate and stomatal conductance decreased in the both varieties during the progression of submergence as compared to the control plants, but significant varietal differences were observed after 1 d of submergence. Submergence also altered the PSII activity, as reflected in a decrease in the values of Fo, Fm and Fv/Fm and degradation of chlorophyll, more in Swarna than in Swarna-Subl. During early submergence period, the activities of superoxide dismutase （SOD）, ascorbate peroxidase （APX）, dehydroascorbate reductase （DHAR）, glutathione reductase （GR） against reactive oxygen species were increased in the both varieties. However, with the progress of submergence period （after 7 d）, the activities of SOD, catalase （CAT）, APX, guaiacol peroxidase （GPX）, GR and DHAR declined, more in Swarna than in Swarna-Subl. During re-aeration, Swarna-Subl showed significant increase of above antioxidant enzymes but not in Swarna, Swarna-Subl improves photosynthetic activity, showing higher photosynthetic rate compared to Swarna under submergence and subsequent re-aeration because of less degradation of chlorophyll, higher stomatal conductance, and efficient PSII activity along with better antioxidant protection from oxidative damage.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(KSCX2-EW-N-01)
文摘One sequence tagged site marker Subl-1 and twice submergence stress method were used in selection of submergence tolerant homozygous line from Sub-lBS, a submergence tolerant, bentazon sensitive and photoperiod-sensitive and/or thermo-sensitive genic male sterile line that developed by our laboratory. The results revealed that the original Sub-lBS was heterozygous in SublA-1 locus even though it was identical in almost all of agronomical traits and the segregation of SublA-1 was in accordance with Mendelian law based on chi-square test. And then the original Sub-IBS was divided into two groups： one was ofSublA-1 introgression and the other was not; and the two groups were tested by twice submergence stress method. After the first submergence stress that lasted for 12 d, the average plant heights were significant difference at the 1% level between the two groups. After recovery for 10 d, the second submergence stress sustained for 18 d was carried on; and the group with SublA-1 gene was found apparently tolerant than the other group in submergence tolerance.
基金supported by German Federal Ministry from Economic Cooperation and Development (BMZ)
文摘Submergence is a serious environmental condition that causes large loss in rice production in rain fed lowland and flood affected area. This study evaluated morphological and physiological responses of rice roots to submergence using two tolerant rice genotypes FR13A and Swarna-Sub 1 and two sensitive ones Swarna and IR42. The tolerant genotypes had higher survival rate and less shoot elongation but greater root elongation during submergence than the sensitive ones. After submergence,the tolerant genotypes also had higher root dry weight and more active roots than the sensitive ones.Tolerant genotypes exhibited less root injury, with less malondialdehyde production and slower electrolyte leakage after submergence. Tolerant genotypes also maintained higher concentrations of soluble sugar and starch in roots and shoots and higher chlorophyll retention after submergence than the sensitive ones.Our data showed that root traits such as root activity and root growth are associated with survival rate after submergence. This is probably accomplished through higher energy supply, and membrane integrity is necessary to preserve root function and reduce injury during submergence. These root traits are important for submergence tolerance in rice.
基金supported by the Natural Science Foundation of Jiangsu,China(BK2011668)the China Agriculture Research System(CARS-13)the National Key Technology Research and Development Program of China(2010-BAD01B10)
文摘Ethylene response factor proteins play an important role in regulating a variety of stress responses in plants,but their exact functions in submergence stress are not well understood.In this study,we isolated BnE RF2.4 from Brassica napus L.to study its function in submergence tolerance.The expression of the BnE RF2.4 gene in B.napus and the expression of antioxidant enzyme genes in transgenic Arabidopsis were analyzed by quantitative RT-PCR.The expression of BnE RF2.4 was induced by submergence in B.napus and the overexpression of BnE RF2.4 in Arabidopsis increased the level of tolerance to submergence and oxidative stress.A histochemical method detected lower levels of H_2O_2,O^(·-)_2and malondialdehyde(MDA) in transgenic Arabidopsis.Compared to the wild type,transgenic lines also had higher soluble sugar content and higher activity of antioxidant enzymes,which helped to protect plants against the oxidative damage caused by submergence.It was concluded that BnE RF2.4 increased the tolerance of plants to submergence stress and may be involved in regulating soluble sugar content and the antioxidant system in defense against submergence stress.
文摘Two variable charge soils were submerged after the addition of 30g/kg of organic matter to examine the differences in behavior between iron and manganese with respect to reduction and the distribution of different forms of the reduced elements. The reduction of manganese proceeded almost synchronously with the fall in redox potential, while the reduction of iron showed a remarkable lag behind the Eh change. Once formed,the distribution of water-soluble, exchangeable and precipitated forms of ferrous iron was controlled by PH,CEC of the soil and total concentration of the element. For manganous ions, the proportions of water-soluble and exchangeable forms in total Mn(2+) were larger than those for ferrous ions. The reduction of the two elements led to a mobilization of them, and such effect persisted even after drying of the soil, i.e.,the content of amorphous Fe became higher than that of the original soil.
文摘Rice line 1892S is an elite thermo-sensitive genic male sterile(TGMS)line for two-line hybrid rice production.However,1892S is susceptible to rice blast,bacterial blight and submergence.Here we reported the introduction of blast resistance(R)gene Pi9,bacterial blight R gene Xa21 and submergence tolerance gene Sub1A into 1892S genetic background through backcrossing and marker-assisted selection.The improved TGMS line 31892S and its hybrids conferred disease resistance to rice blast and bacterial blight,and showed submergence tolerance for over 14 d without significant loss of viability.The sterility-fertility conversion of 31892S was similar to that of 1892S.31892S and its derived hybrid rice had similar agronomic traits and grain quality with 1892S and the control hybrid rice,respectively.The newly developed 31892S provided an improved TGMS line for two-line hybrid rice production with disease resistance to rice blast and bacterial blight,and submergence tolerance with no yield penalty or change in grain quality.
文摘The present study evaluated submergence responses in 88 lowland indigenous rice(Oryza sativa L.) landraces from Koraput, India, to identify submergence-tolerant rice genotypes. In pot experiments, variations in survival rate, shoot elongation, relative growth index, dry matter, chlorophyll, soluble sugar and starch contents were evaluated in two consecutive years under well-drained and completely submerged conditions. Principal component analysis showed that the first three axes contributed 96.820% of the total variation among the landraces, indicating wide variation between genotypes. Major traits such as survival rate, relative growth index, soluble sugar and starch contents appeared to be important determinants of phenotypic diversity among the landraces. Phenotypic coefficient of variance was higher than genotypic coefficient of variance for all the traits and all showed high heritability(90.38%–99.54%). Five rice landraces(Samudrabali, Basnamundi, Gadaba, Surudaka and Dokarakuji) were the most tolerant to submergence. When submerged for up to 14d, Samudrabali, Basnamundi and Godoba were notable for having greater survival rates than a standard submergence tolerant variety FR13 A, and also notable for elongating more vigorously and accumulating more biomass. These three landraces may therefore be especially useful in lowland rice growing areas that are affected by both moderate stagnant water and flash flooding. Molecular genotyping revealed that the submergence tolerance of Samudrabali, Basnamundi and Godoba is linked to the presence of one or more different Sub1 loci and it may well prove useful for breeding improved submergence tolerant rice varieties, thereby assising to improve yield stability in the rainfed lowland agro-ecosystem.
文摘In the present study a group of four indigenous and less popular rice genotypes (Meghi, Panibhasha, Jabra and Sholey) reported by growers as submergence tolerant lines from flood prone areas of south Bengal were explored through study of nodal anatomy, physio-biochemical screening under submergence and genotyping with submergence tolerance linked rice microsatellite loci (RM loci). To identify the different allelic forms of different Sub1 compnents (Sub1A, Sub1B and Sub1C) among the studied lines, the genomic DNA of individual genotypes was amplified with three ethylene response factor like genes from Sub1 loci, located on rice chromosome 9. From the different physio-biochemical experiments performed in this investigation, it has been shown that Meghi and Jabra are the two probable potent genotypes which share common properties of both submergence tolerant and deep water nature whereas rest two genotypes (Sholey and Panibhasha) behave like typical deep water rice. The submergence tolerance property of Meghi was also confirmed from submergence tolerance linked SSR based genotyping by sharing with FR13A for some common alleles as reflected in fingerprint derived dendrogram. The rest of the genotypes shared a number of alleles and were included in a separate cluster. The common behaviour of Meghi and FR13A under submergence was also confirmed from genetic study of Sub1 loci through sharing of some common alleles for three Sub1 components (Sub1A, Sub1B and Sub1C loci). One SSR loci (RM 285) was identified as a potent molecular marker for submergence tolerance breeding programme involving these two selected rice lines (Meghi and Jabra) as donor plant through marker assisted selection.
文摘Three rice varieties, significantly differed in their ability, when subjected to submergence have been studied in relation to physiological attributes. On account of oxidative stress, MDA content and carbonyl content were measured. The MDA content was maximally decreased in FR13A and minimally decreased in Swarna irrespective of shoots and roots. A higher increase in carbonyl content was found in Swarna followed by FR13A and Swarna Sub1A in both shoots and roots. The activity of antioxidant moieties like total phenolics content and flavonoid content were more increased under submergence than that in air except for Swarna. FR13A showed maximum increase in Phenolics and flavonoid content in both shoots and roots when subjected to submergence. A sharp increase in guaiacol peroxidase and glutathione reductase characterized the plants’ response to sub-mergence irrespective of varieties. The expression of Guaiacol peroxidase was increased in FR13A followed by Swarna Sub1A and Swarna. Glutathione reductase was measured in terms of oxidation of NADP(H) and both FR13A and Swarna Sub1A recorded maximum oxidation than Swarna under submergence. With regards to isozymic variation plants were differed to the intensities of poly-peptide, however not in numbers and may be suggestive for concomitant gene expression to sub-mergence. The analysis clarification for possible biomarkers with regards to cellular responses of rice plants under submergence has been anticipated.
文摘Flash flood or submergence is a common phenomenon in rice growing rainfed lowland areas that seriously affects crop establishment leading to severe yield losses. A few submergence-tolerant rice varieties have been developed by introgressing SUB1 gene into mega rice varieties of South Asia. Two of these, Swarna-Sub1 and Sambha Mahsuri-Sub1, are already released in India for the commercial cultivation. Performance of these varieties can be further enhanced through adoption of appropriate management practices both in nursery and in main field. Two on-station field experiments were conducted using Swarna-Sub1 during the wet season (kharif) of 2011 at Rice Research Station, Chinsurah, Hooghly, West Bengal (India). Results of these experiments revealed that the use of lower seeding density (25 g m-2), application of balanced doses of N-P2O5-K2O @ 80-40-40 kg ha-1 in nursery and transplanting of aged seedlings (44 days) significantly improved plant survival, yield attributing traits and grain yield. An additional N-dose of 20 kg ha-1 at 7 days after receding of flood water resulted in better post-submergence recovery and maximum grain yield. In the on-farm trials conducted at three different locations in West Bengal, nursery raising of seedlings with the application of N-P2O5-K2O @ 80-40-40 kg ha-1, transplanting them at an optimum age (35 days) and application of 20 kg·N ha-1 after 7 days of de-submergence produced maximum grain yield of Swarna-Sub1.
基金Acknowledgements The authors thank Mary Roth （Kansas Lipidomics Research Center） for her assistance with the lipid analysis, Dr. Yanxia Jia for the use of the IMAGING-PAM chlorophyll fluorometer.
文摘The composition of membrane lipids is sensitive to environmental stresses.Submergence is a type of stress often encountered by plants.However,how the molecular species of membrane lipids respond to submergence has not yet been characterised.In this study,we used a lipidomic approach to profile the molecular species of membrane lipids in whole plants of Arabidopsis thaliana that were completely submerged for three days.The plants survived one day of submergence,after which,we found that the total membrane lipids were only subtly decreased,showing significant decreases of monogalactosyldiacylglycerol(MGDG)and phosphatidylcholine(PC)and an increase of phosphatidic acid(PA);however,the basic lipid composition was retained.In contrast,three days of submergence caused plants to die,and the membranes deteriorated via the rapid loss of 96% of lipid content together with a 229% increase in PA.The turnover of molecular species from PG and MGDG to PA indicated that submergenceinduced lipid changes occurred through PA-mediated degradation.In addition,molecular species of extraplastidic PG degraded sooner than plastidic ones,lyso-phospholipids exhibited various patterns of change,and the double-bond index(DBI)remained unchanged until membrane deterioration.Our results revealed the unique changes of membrane lipids upon submergence and suggested that the major cause of the massive lipid degradation could be anoxia.
文摘The detrimental effects of submergence on physiological performances of some rice varieties with special references to carbohydrate metabolisms and their allied enzymes during post-flowering stages have been documented and clarified in the present investigation. It was found that photosynthetic rate and concomitant translocation of sugars into the panicles were both related to the yield. The detrimental effects of the complete submergence were recorded in generation of sucrose, starch, sucrose phosphate synthase and phosphorylase activity in the developing panicles of the plants as compared to those under normal or control （i.e. non-submerged） condition. The accumulation of starch was significantly lower in plants under submergence and that was correlated with ADP-glucose pyrophosphorylase activity. Photosynthetic rate was most affected under submergence in varying days of post-flowering and was also related to the down regulation of Ribulose bisphosphate carboxylase activity. However, under normal or control condition, there recorded a steady maintenance of photosynthetic rate at the post-flowering stages and significantly higher values of Ribulose bisphosphate carboxylase activity. Still, photosynthetic rate of the plants under both control and submerged conditions had hardly any significant correlation with sugar accumulation and other enzymes of carbohydrate metabolism like invertase with grain yield. Finally, plants under submergence suffered significant loss of yield by poor grain filling which was related to impeded carbohydrate metabolism in the tissues. It is evident that loss of yield under submergence is attributed both by lower sink size or sink capacity （number of panicles, in this case） as well as subdued carbohydrate metabolism in plants and its subsequent partitioning into the grains.
基金A part of the project supported by the Laboratory of Material Cycling in Pedosphere, Academia Sinica.
文摘A thermostatic incubation experiment was carried out to estimate the effects of flooding periods, stalk application and P addition on Fe transformation and P availability in calcareous soils. Submergence increased amorphous Fe, especially in the case of stalk application. The newly formed amorphous Fe with a great surface area played an important role in P sorption; and submergence also stimulated the dissolution of inorganic P, thus increasing the availability of soil P in calcareous soils. Meanwhile, a part of soluble P was adsorbed and fixed again on the surface of newly formed amorphous Fe, thus resulting in a decrease of P availability. Soil rapidly available P increased after ISO-day incubation. There existed significantly negative correlations between soil amorphous Fe content and soil Fe-P and rapidly available P contents. Submerged conditions promoted the transformation of inorganic P added to-ward Fe-P in calcareous soils, especially in the case of stalk application.
基金supported in part by a grant from the German Federal Ministry for Economic Cooperation and Development and Bill and Melinda Gates Foundation
文摘Submergence tolerant high yielding rice variety was developed using BR11 as a recipient parent applying foreground, phenotypic and background selection approaches. Recombinant selection was found essential to minimize linkage drag by BC2F2 generation. Without recombinant selection, the introgression size in the backcross recombinant lines （BRLs） was approximately 15 Mb on the carrier chromosome. The BRLs were found submergence tolerance compared to the check varieties under complete submergence for two weeks at Bangladesh Rice Research Institute, and produced higher yield compared to the isogenic Subl-line under controlled submerged condition. The BRL IR85260-66-654-Gaz2 was released as BRRI dhan52 in 2010, which was the first high yielding submergence tolerant variety in Bangladesh. BRRI dhan52 produced grain yield ranging from 4.2 to 5.2 t/hm2 under different flash flood prone areas of Bangladesh in three consecutive seasons. The study demonstrated the efficiency of recombinant selection and better adaptability of the newly released submergence tolerant high yielding variety in flash flood prone different areas of the country with respect to submergence tolerance and yield potential.
文摘In this paper, the influence depths of all levels of wind power produced waves are reckoned according to the measured swaying degree when a submarine meets with a force 11 strong tropical storm and has to submerge; Then the minimum submergence depth is given when a submarine is faced with weather systems with force ≥ 6 wind and the swaying degree of less than 12 degree is assured as reference for a submarine working and sailing in big strong winds and waves.
文摘The result of the study contributes to enhancing and sustaining future livelihoods and food security in Vietnam vis-a-vis climate change. An innovative strategy based on marker-assisted backcrossing (MABC) was used to transform popular rice variety AS996 into the one can tolerate submergence while maintaining its original characteristics preferred by farmers and consumers. The submergence tolerance QTL SUB1 counts for up to 70% of the submergence tolerant and provides a marked improvement of submergence tolerance in all genetic backgrounds and environments tested so far. Parental diversity was carried out with 460 markers. Of which, 53 polymorphic markers were used for assessment on BC1F1, BC2F1 and BC3F1 generations. The best BC1F1 plant was P422 with highest recipient allele was 87.5%, while the additional chosen plants were P412, P428, P215 and P39 (81% - 84%). All these plants were used to develop BC2F1 generation. The six BC2F1 plants were used to develop BC3F1 and BC2F2 were the plants number P422-11 and P422-14 having 93.75% recipient alleles and P422-12, P422-3, P39-17, P39-25 having 92.25% recipient alleles. Total of 445 BC3F1 plants were confirmed the introgresion of SUB1 using ART5 and SC3. After three generations of backcrossing, application of MABC resulted in the best BC3F1 individual P422-14-177 with 100% of recipient alleles based on the number of 53 markers used with only the introgression size of SUB1 was 0.3Mb between ART5 and SC3. Phenotyping was carried out on BC3F1 and BC2F2 of the selected lines. The survival ratio of these selected lines and IR64SUB1 were the same. It convinced the successfully introgress SUB1 into AS996 rice variety. The breeding line BC4F1 having 100% genetic background of donor variety is ready for develop new submergence tolerant rice variety ASS996-SUB1 to cope with climate change.
