cDNA libraries were constructed from the leaves of a rice (Oryza sativa L.) salt tolerancevariety Tesan抋i 2 growing in solutions with 150 mmol/L NaCl for 3 h or without salt stress. Three salt-responsive cDNA clones,...cDNA libraries were constructed from the leaves of a rice (Oryza sativa L.) salt tolerancevariety Tesan抋i 2 growing in solutions with 150 mmol/L NaCl for 3 h or without salt stress. Three salt-responsive cDNA clones, Ts1, Ts2 and Ts3 were isolated by differential screening. Northern blottinganalysis showed that the transcription levels of Ts1 and Ts2 increased within 3 h salt stress and kept onincreasing within 24 h, while the transcription level of Ts3 reached its peak within 3 h. Sequence analysisindicated that there were no homologies between the three cDNA clones and any known gene. The threecDNA clones were mapped using a doubled haploid (DH) population derived from an indica variety ZYQ8,which was a salt tolerance parent of Tesan抋i 2, with a japonica variety JX17. Ts1, Ts2 and Ts3 werelocated on chromosomes 1, 3 and 7, respectively. It was noted that Ts1, Ts2, and Ts3 were in or near theregions of major or minor salt tolerance quantitative trait loci (QTLs), which were mapped in the same DHpopulation in a parallel study.展开更多
[Objective] Marine sediment from Tianjin Port has a extremely high salinity.The bacteria which live in such habitats have evolved distinct physiological,metabolic,and morphological characteristics to survive.The objec...[Objective] Marine sediment from Tianjin Port has a extremely high salinity.The bacteria which live in such habitats have evolved distinct physiological,metabolic,and morphological characteristics to survive.The objective of this study is to identify all the specific salt-tolerant characteristics and the genetic evolution of the bacteria in the sediment.[Methods] In this study,the total DNA of sediment from Tianjin Port was extracted,and 16S rDNA was used to conduct an analysis of the fauna of sediment bacteria. We also isolated sediment bacteria using beef extract-peptone media with seven different NaCl concentrations (0,0.5%,2%,5%,10%,15%,and 20%),aiming to analyze the dominant species of halophilous bacteria under different salinities.[Results] 1) With each stepwise increase of salinity from 0.5% to 20%,the total number of isolated bacterial colonies decreased.14 strains of bacteria were identified and classified by the16S rDNA sequencing analysis.Of these,four could tolerate 0~2% salinity,four could tolerate 0~5% salinity,one could tolerate 0~15% salinity,and one tolerated within the full 0~20% salinity range.Further four strains were only able to tolerate within a few narrow salinity ranges.such as 5%~10%,10%~15%,10%~20% and 15%~20%;2) The quantity of bacteria strains that can be isolated from the marine sediment decreased with the increase of salinity. Also, the Shannon wiener index and species richness index of marine sediment bacteria decreased significantly from 5% salinity.However,there were no significant differences in the species evenness index;3) When the salinity was 0~10%,the dominant species was Bacillus.When the salinity was 15%, Halomonas was the dominant species.When the salinity was 20%,there were no significant differences in the proportions of these species.[Conclusion] Our results showed that some bacteria could tolerate living conditions with high salinity,and we even found a species which can tolerate a wide range of salinities (0~20%).In further study,it would be valuable to analyze these bacteria's unique physiological and biochemical functions that allow them to adapt to environments with high salinity.It can provide theories to promote the development of microbial population resources in marine sediment and the reclaimation of salinized soil by salt tolerant microorganisms.展开更多
The role of mycorrhizal symbiosis in the alleviation of salinity stress induced by sodium chloride （NaCI） was investigated. Three artichoke hybrids, Madrigal F1, Opal FI, and Concerto FI （Nunhems company）, were gr...The role of mycorrhizal symbiosis in the alleviation of salinity stress induced by sodium chloride （NaCI） was investigated. Three artichoke hybrids, Madrigal F1, Opal FI, and Concerto FI （Nunhems company）, were grown in pot in controlled environment with two different mycorrhizal treatments （with or without Glomus viscosum）. Two months after inoculation, the fungus established well on roots of the Madrigal and Opal plants with higher colonization and dependency values, instead the Concerto plants showed lower mycorrhizal dependency and colonization rate. Mycorrhizal symbiosis generally improved plant vegetative growth and sustained plant physiology increasing stomatal conductance and SPAD values. The root systems of two months old artichoke plantlets, both inoculated and non inoculated, were placed in distilled water enriched with different salt concentrations （0, 100, 150, 200, 250 mM NaCI） to study the wilting response. A visual rating system was developed defining various wilting indexes （TO, no wilting; T1, foliar damage on less than 50% of vegetal tissues of basal leaves; T2, initial wilting and foliar damage on more than 50% of vegetal tissues of basal leaves; T3, foliar damage on the apical leaves; and T4, total wilting）. Mycorrhizal plants reached later the wilting indexes than non-mycorrhizal plants. Electrolyte leakage by leaves after salinity imposition was higher in non-mycorrhizal plants and the vegetal tissues were severely damaged especially in the basal leaves. The greater tolerance observed in the mycorrhizal plants could be in agreement with the improvement in growth stimulated by mycorrhizal symbiosis, which leads to the dilution of toxic ions.展开更多
The plant hormone abscisic acid(ABA)is crucial for plant seed germination and abiotic stress tolerance.However,the association between ABA sensitivity and plant abiotic stress tolerance remains largely unknown.In this...The plant hormone abscisic acid(ABA)is crucial for plant seed germination and abiotic stress tolerance.However,the association between ABA sensitivity and plant abiotic stress tolerance remains largely unknown.In this study,436 rice accessions were assessed for their sensitivity to ABA during seed germination.The considerable diversity in ABA sensitivity among rice germplasm accessions was primarily reflected by the differentiation between the Xian(indica)and Geng(japonica)subspecies and between the upland-Geng and lowland-Geng ecotypes.The upland-Geng accessions were most sensitive to ABA.Genome-wide association analyses identified four major quantitative trait loci containing21 candidate genes associated with ABA sensitivity of which a basic helix-loop-helix transcription factor gene,OsbHLH38,was the most important for ABA sensitivity.Comprehensive functional analyses using knockout and overexpression transgenic lines revealed that OsbHLH38 expression was responsive to multiple abiotic stresses.Overexpression of OsbHLH38 increased seedling salt tolerance,while knockout of OsbHLH38 increased sensitivity to salt stress.A salt-responsive transcription factor,OsDREB2A,interacted with OsbHLH38 and was directly regulated by OsbHLH38.Moreover,OsbHLH38 affected rice abiotic stress tolerance by mediating the expression of a large set of transporter genes of phytohormones,transcription factor genes,and many downstream genes with diverse functions,including photosynthesis,redox homeostasis,and abiotic stress responsiveness.These results demonstrated that OsbHLH38 is a key regulator in plant abiotic stress tolerance.展开更多
文摘cDNA libraries were constructed from the leaves of a rice (Oryza sativa L.) salt tolerancevariety Tesan抋i 2 growing in solutions with 150 mmol/L NaCl for 3 h or without salt stress. Three salt-responsive cDNA clones, Ts1, Ts2 and Ts3 were isolated by differential screening. Northern blottinganalysis showed that the transcription levels of Ts1 and Ts2 increased within 3 h salt stress and kept onincreasing within 24 h, while the transcription level of Ts3 reached its peak within 3 h. Sequence analysisindicated that there were no homologies between the three cDNA clones and any known gene. The threecDNA clones were mapped using a doubled haploid (DH) population derived from an indica variety ZYQ8,which was a salt tolerance parent of Tesan抋i 2, with a japonica variety JX17. Ts1, Ts2 and Ts3 werelocated on chromosomes 1, 3 and 7, respectively. It was noted that Ts1, Ts2, and Ts3 were in or near theregions of major or minor salt tolerance quantitative trait loci (QTLs), which were mapped in the same DHpopulation in a parallel study.
文摘[Objective] Marine sediment from Tianjin Port has a extremely high salinity.The bacteria which live in such habitats have evolved distinct physiological,metabolic,and morphological characteristics to survive.The objective of this study is to identify all the specific salt-tolerant characteristics and the genetic evolution of the bacteria in the sediment.[Methods] In this study,the total DNA of sediment from Tianjin Port was extracted,and 16S rDNA was used to conduct an analysis of the fauna of sediment bacteria. We also isolated sediment bacteria using beef extract-peptone media with seven different NaCl concentrations (0,0.5%,2%,5%,10%,15%,and 20%),aiming to analyze the dominant species of halophilous bacteria under different salinities.[Results] 1) With each stepwise increase of salinity from 0.5% to 20%,the total number of isolated bacterial colonies decreased.14 strains of bacteria were identified and classified by the16S rDNA sequencing analysis.Of these,four could tolerate 0~2% salinity,four could tolerate 0~5% salinity,one could tolerate 0~15% salinity,and one tolerated within the full 0~20% salinity range.Further four strains were only able to tolerate within a few narrow salinity ranges.such as 5%~10%,10%~15%,10%~20% and 15%~20%;2) The quantity of bacteria strains that can be isolated from the marine sediment decreased with the increase of salinity. Also, the Shannon wiener index and species richness index of marine sediment bacteria decreased significantly from 5% salinity.However,there were no significant differences in the species evenness index;3) When the salinity was 0~10%,the dominant species was Bacillus.When the salinity was 15%, Halomonas was the dominant species.When the salinity was 20%,there were no significant differences in the proportions of these species.[Conclusion] Our results showed that some bacteria could tolerate living conditions with high salinity,and we even found a species which can tolerate a wide range of salinities (0~20%).In further study,it would be valuable to analyze these bacteria's unique physiological and biochemical functions that allow them to adapt to environments with high salinity.It can provide theories to promote the development of microbial population resources in marine sediment and the reclaimation of salinized soil by salt tolerant microorganisms.
文摘The role of mycorrhizal symbiosis in the alleviation of salinity stress induced by sodium chloride （NaCI） was investigated. Three artichoke hybrids, Madrigal F1, Opal FI, and Concerto FI （Nunhems company）, were grown in pot in controlled environment with two different mycorrhizal treatments （with or without Glomus viscosum）. Two months after inoculation, the fungus established well on roots of the Madrigal and Opal plants with higher colonization and dependency values, instead the Concerto plants showed lower mycorrhizal dependency and colonization rate. Mycorrhizal symbiosis generally improved plant vegetative growth and sustained plant physiology increasing stomatal conductance and SPAD values. The root systems of two months old artichoke plantlets, both inoculated and non inoculated, were placed in distilled water enriched with different salt concentrations （0, 100, 150, 200, 250 mM NaCI） to study the wilting response. A visual rating system was developed defining various wilting indexes （TO, no wilting; T1, foliar damage on less than 50% of vegetal tissues of basal leaves; T2, initial wilting and foliar damage on more than 50% of vegetal tissues of basal leaves; T3, foliar damage on the apical leaves; and T4, total wilting）. Mycorrhizal plants reached later the wilting indexes than non-mycorrhizal plants. Electrolyte leakage by leaves after salinity imposition was higher in non-mycorrhizal plants and the vegetal tissues were severely damaged especially in the basal leaves. The greater tolerance observed in the mycorrhizal plants could be in agreement with the improvement in growth stimulated by mycorrhizal symbiosis, which leads to the dilution of toxic ions.
基金supported by the National Key Research and Development Program of China(2020YFE0202300)the National Natural Science Foundation of China(31971928)+2 种基金the Hainan Yazhou Bay Seed Lab Project(B23CJ0208,B21HJ0223,and B21HJ0508)the CAAS Innovative Team Award(to BYF and WSW)the National High-level Personnel of Special Support Program(to WSW)。
文摘The plant hormone abscisic acid(ABA)is crucial for plant seed germination and abiotic stress tolerance.However,the association between ABA sensitivity and plant abiotic stress tolerance remains largely unknown.In this study,436 rice accessions were assessed for their sensitivity to ABA during seed germination.The considerable diversity in ABA sensitivity among rice germplasm accessions was primarily reflected by the differentiation between the Xian(indica)and Geng(japonica)subspecies and between the upland-Geng and lowland-Geng ecotypes.The upland-Geng accessions were most sensitive to ABA.Genome-wide association analyses identified four major quantitative trait loci containing21 candidate genes associated with ABA sensitivity of which a basic helix-loop-helix transcription factor gene,OsbHLH38,was the most important for ABA sensitivity.Comprehensive functional analyses using knockout and overexpression transgenic lines revealed that OsbHLH38 expression was responsive to multiple abiotic stresses.Overexpression of OsbHLH38 increased seedling salt tolerance,while knockout of OsbHLH38 increased sensitivity to salt stress.A salt-responsive transcription factor,OsDREB2A,interacted with OsbHLH38 and was directly regulated by OsbHLH38.Moreover,OsbHLH38 affected rice abiotic stress tolerance by mediating the expression of a large set of transporter genes of phytohormones,transcription factor genes,and many downstream genes with diverse functions,including photosynthesis,redox homeostasis,and abiotic stress responsiveness.These results demonstrated that OsbHLH38 is a key regulator in plant abiotic stress tolerance.
