Foxtail millet(Setaria italica L.)with high drought resistance,is grown widely in arid and semi-arid regions of the world,and it is a new model plant for genetic and molecular studies.To uncover the molecular mechanis...Foxtail millet(Setaria italica L.)with high drought resistance,is grown widely in arid and semi-arid regions of the world,and it is a new model plant for genetic and molecular studies.To uncover the molecular mechanisms of stress-tolerance in different genotypes of foxtail millet,physiological analyses combined with transcriptional profiling were conducted using a time-course analysis on two foxtail millet genotypes Damaomao(DM)and Hongnian(HN).The genotype DM performed better than HN under water deficiency,with more moderate relative water content(RWC)and chlorophyll decline.Further physiological and RNA-seq investigations revealed that the two genotypes possessed high conservatism in some vital biological pathways which respond to drought stress,involving hormone synthesis,proline,and soluble sugar synthesis,and reactive oxygen species(ROS)metabolism.However,some genes related to these pathways showed different expression profiles.Likewise,the lower malondialdehyde(MDA)content in HN than DM may be explained by the observation that HN contained more activated genes in the ascorbate-glutathione cycle using KEGG pathway analysis.Overall,abscisic acid(ABA)response genes,ROS scavengers which were probably involved in signaling responses,a set of enzymes involved in proline and soluble sugar synthesis,channel protein genes,and transcription factors,encompassed the early strategy of foxtail millet response to drought.These findings provide a comprehensive molecular view of how different foxtail millet genotypes respond to short-term osmotic stress.展开更多
Foxtail millet（Setaria italica（L.）P.Beauv）is a naturally stress tolerant crop.Compared to other gramineous crops,it has relatively stronger drought and lower nutrition stress tolerance traits.To date,the scope of ...Foxtail millet（Setaria italica（L.）P.Beauv）is a naturally stress tolerant crop.Compared to other gramineous crops,it has relatively stronger drought and lower nutrition stress tolerance traits.To date,the scope of functional genomics research in foxtail millet（S.italic L.）has been quite limited.NAC（NAM,ATAF1/2 and CUC2）-like transcription factors are known to be involved in various biological processes,including abiotic stress responses.In our previous foxtail millet（S.italic L.）RNA seq analysis,we found that the expression of a NAC-like transcription factor,SiNAC110,could be induced by drought stress;additionally,other references have reported that SiNAC110 expression could be induced by abiotic stress.So,we here selected SiNAC110 for further characterization and functional analysis.First,the predicted SiNAC110 protein encoded indicated SiNAC110 has a conserved NAM（no apical meristem）domain between the 11–139 amino acid positions.Phylogenetic analysis then indicated that SiNAC110 belongs to subfamily III of the NAC gene family.Subcellular localization analysis revealed that the SiNAC110-GFP fusion protein was localized to the nucleus in Arabidopsis protoplasts.Gene expression profiling analysis indicated that expression of SiNAC110 was induced by dehydration,high salinity and other abiotic stresses.Gene functional analysis using SiNAC110 overexpressed Arabidopsis plants indicated that,under drought and high salt stress conditions,the seed germination rate,root length,root surface area,fresh weight,and dry weight of the SiNAC110 overexpressed lines were significantly higher than the wild type（WT）,suggesting that the SiNAC110 overexpressed lines had enhanced tolerance to drought and high salt stresses.However,overexpression of SiN AC110 did not affect the sensitivity of SiNAC110 overexpressed lines to abscisic acid（ABA）treatment.Expression analysis of genes involved in proline synthesis,Na＋/K＋transport,drought responses,and aqueous transport proteins were higher in the SiNAC110overexpressed lines than in the WT,whereas expression of ABA-dependent pathway genes did not change.These results indicated that overexpression of SiNAC110 conferred tolerance to drought and high salt stresses,likely through influencing the regulation of proline biosynthesis,ion homeostasis and osmotic balance.Therefore,SiNAC110 appears to function in the ABA-independent abiotic stress response pathway in plants.展开更多
基金supported by the earmarked fund for China Agriculture Research System (CARS-06-13.5-A26)the National Natural Science Foundation of China (31371529)the Minor Grain Crops Research and Development System of Shaanxi Province, China (2014–2017)
文摘Foxtail millet(Setaria italica L.)with high drought resistance,is grown widely in arid and semi-arid regions of the world,and it is a new model plant for genetic and molecular studies.To uncover the molecular mechanisms of stress-tolerance in different genotypes of foxtail millet,physiological analyses combined with transcriptional profiling were conducted using a time-course analysis on two foxtail millet genotypes Damaomao(DM)and Hongnian(HN).The genotype DM performed better than HN under water deficiency,with more moderate relative water content(RWC)and chlorophyll decline.Further physiological and RNA-seq investigations revealed that the two genotypes possessed high conservatism in some vital biological pathways which respond to drought stress,involving hormone synthesis,proline,and soluble sugar synthesis,and reactive oxygen species(ROS)metabolism.However,some genes related to these pathways showed different expression profiles.Likewise,the lower malondialdehyde(MDA)content in HN than DM may be explained by the observation that HN contained more activated genes in the ascorbate-glutathione cycle using KEGG pathway analysis.Overall,abscisic acid(ABA)response genes,ROS scavengers which were probably involved in signaling responses,a set of enzymes involved in proline and soluble sugar synthesis,channel protein genes,and transcription factors,encompassed the early strategy of foxtail millet response to drought.These findings provide a comprehensive molecular view of how different foxtail millet genotypes respond to short-term osmotic stress.
基金funded by the National Key Project for Research on Transgenic Biology, China (2016ZX08002-002)the Innovation Project of Chinese Academy of Agricultural Sciences
文摘Foxtail millet（Setaria italica（L.）P.Beauv）is a naturally stress tolerant crop.Compared to other gramineous crops,it has relatively stronger drought and lower nutrition stress tolerance traits.To date,the scope of functional genomics research in foxtail millet（S.italic L.）has been quite limited.NAC（NAM,ATAF1/2 and CUC2）-like transcription factors are known to be involved in various biological processes,including abiotic stress responses.In our previous foxtail millet（S.italic L.）RNA seq analysis,we found that the expression of a NAC-like transcription factor,SiNAC110,could be induced by drought stress;additionally,other references have reported that SiNAC110 expression could be induced by abiotic stress.So,we here selected SiNAC110 for further characterization and functional analysis.First,the predicted SiNAC110 protein encoded indicated SiNAC110 has a conserved NAM（no apical meristem）domain between the 11–139 amino acid positions.Phylogenetic analysis then indicated that SiNAC110 belongs to subfamily III of the NAC gene family.Subcellular localization analysis revealed that the SiNAC110-GFP fusion protein was localized to the nucleus in Arabidopsis protoplasts.Gene expression profiling analysis indicated that expression of SiNAC110 was induced by dehydration,high salinity and other abiotic stresses.Gene functional analysis using SiNAC110 overexpressed Arabidopsis plants indicated that,under drought and high salt stress conditions,the seed germination rate,root length,root surface area,fresh weight,and dry weight of the SiNAC110 overexpressed lines were significantly higher than the wild type（WT）,suggesting that the SiNAC110 overexpressed lines had enhanced tolerance to drought and high salt stresses.However,overexpression of SiN AC110 did not affect the sensitivity of SiNAC110 overexpressed lines to abscisic acid（ABA）treatment.Expression analysis of genes involved in proline synthesis,Na＋/K＋transport,drought responses,and aqueous transport proteins were higher in the SiNAC110overexpressed lines than in the WT,whereas expression of ABA-dependent pathway genes did not change.These results indicated that overexpression of SiNAC110 conferred tolerance to drought and high salt stresses,likely through influencing the regulation of proline biosynthesis,ion homeostasis and osmotic balance.Therefore,SiNAC110 appears to function in the ABA-independent abiotic stress response pathway in plants.
