Cotton provides the most abundant natural fiber for the textile industry.The mature cotton fiber largely consists of secondary cell walls with the highest proportion of cellulose and a small amount of hemicellulose an...Cotton provides the most abundant natural fiber for the textile industry.The mature cotton fiber largely consists of secondary cell walls with the highest proportion of cellulose and a small amount of hemicellulose and lignin.To dissect the roles of hemicellulosic polysaccharides during fiber development,four IRREGULAR XYLEM 15(IRX15)genes,GhIRX15-1/-2/-3/-4,were functionally characterized in cotton.These genes encode DUF579 domain-containing proteins,which are homologs of AtIRX15 involved in xylan biosynthesis.The four GhIRX15 genes were predominantly expressed during fiber secondary wall thickening,and the encoded proteins were localized to the Golgi apparatus.Each GhIRX15 gene could restore the xylan deficient phenotype in the Arabidopsis irx15irx15l double mutant.Silencing of GhIRX15s in cotton resulted in shorter mature fibers with a thinner cell wall and reduced cellulose content as compared to the wild type.Intriguingly,GhIRX15-2 and GhIRX15-4 formed homodimers and heterodimers.In addition,the GhIRX15s showed physical interaction with glycosyltransferases GhGT43C,GhGT47A and GhGT47B,which are responsible for synthesis of the xylan backbone and reducing end sequence.Moreover,the GhIRX15s can form heterocomplexes with enzymes involved in xylan modification and side chain synthesis,such as GhGUX1/2,GhGXM1/2 and GhTBL1.These findings suggest that GhIRX15s participate in fiber xylan biosynthesis and modulate fiber development via forming large multiprotein complexes.展开更多
The mechanisms underlying rootzone-localized responses to salinity during early stages of barley development remain elusive.In this study,we performed the analyses of multi-root-omes(transcriptomes,metabolomes,and lip...The mechanisms underlying rootzone-localized responses to salinity during early stages of barley development remain elusive.In this study,we performed the analyses of multi-root-omes(transcriptomes,metabolomes,and lipidomes)of a domesticated barley cultivar(Clipper)and a landrace(Sahara)that maintain and restrict seedling root growth under salt stress,respectively.Novel generalized linear models were designed to determine differentially expressed genes(DEGs)and abundant metabolites(DAMs)specific to salt treatments,genotypes,or rootzones(meristematic Z1,elongation Z2,and maturation Z3).Based on pathway over-representation of the DEGs and DAMs,phenylpropanoid biosynthesis is the most statistically enriched biological pathway among all salinity responses observed.Together with histological evidence,an intense salt-induced lignin impregnation was found only at stelic cell wall of Clipper Z2,compared with a unique elevation of suberin deposition across Sahara Z2.This suggests two differential salt-induced modulations of apoplastic flow between the genotypes.Based on the global correlation network of the DEGs and DAMs,callose deposition that potentially adjusted symplastic flow in roots was almost independent of salinity in rootzones of Clipper,and was markedly decreased in Sahara.Taken together,we propose two distinctive salt tolerance mechanisms in Clipper(growth-sustaining)and Sahara(salt-shielding),providing important clues for improving crop plasticity to cope with deteriorating global soil salinization.展开更多
基金supported by the National Natural Science Foundation of China(31970516 and 32372104)the Foundation of Hubei Hongshan Laboratory(2021hszd014).
文摘Cotton provides the most abundant natural fiber for the textile industry.The mature cotton fiber largely consists of secondary cell walls with the highest proportion of cellulose and a small amount of hemicellulose and lignin.To dissect the roles of hemicellulosic polysaccharides during fiber development,four IRREGULAR XYLEM 15(IRX15)genes,GhIRX15-1/-2/-3/-4,were functionally characterized in cotton.These genes encode DUF579 domain-containing proteins,which are homologs of AtIRX15 involved in xylan biosynthesis.The four GhIRX15 genes were predominantly expressed during fiber secondary wall thickening,and the encoded proteins were localized to the Golgi apparatus.Each GhIRX15 gene could restore the xylan deficient phenotype in the Arabidopsis irx15irx15l double mutant.Silencing of GhIRX15s in cotton resulted in shorter mature fibers with a thinner cell wall and reduced cellulose content as compared to the wild type.Intriguingly,GhIRX15-2 and GhIRX15-4 formed homodimers and heterodimers.In addition,the GhIRX15s showed physical interaction with glycosyltransferases GhGT43C,GhGT47A and GhGT47B,which are responsible for synthesis of the xylan backbone and reducing end sequence.Moreover,the GhIRX15s can form heterocomplexes with enzymes involved in xylan modification and side chain synthesis,such as GhGUX1/2,GhGXM1/2 and GhTBL1.These findings suggest that GhIRX15s participate in fiber xylan biosynthesis and modulate fiber development via forming large multiprotein complexes.
基金supported by funding from the Australian Research Council(Future Fellowship:FT130100326)the University of Melbourne.
文摘The mechanisms underlying rootzone-localized responses to salinity during early stages of barley development remain elusive.In this study,we performed the analyses of multi-root-omes(transcriptomes,metabolomes,and lipidomes)of a domesticated barley cultivar(Clipper)and a landrace(Sahara)that maintain and restrict seedling root growth under salt stress,respectively.Novel generalized linear models were designed to determine differentially expressed genes(DEGs)and abundant metabolites(DAMs)specific to salt treatments,genotypes,or rootzones(meristematic Z1,elongation Z2,and maturation Z3).Based on pathway over-representation of the DEGs and DAMs,phenylpropanoid biosynthesis is the most statistically enriched biological pathway among all salinity responses observed.Together with histological evidence,an intense salt-induced lignin impregnation was found only at stelic cell wall of Clipper Z2,compared with a unique elevation of suberin deposition across Sahara Z2.This suggests two differential salt-induced modulations of apoplastic flow between the genotypes.Based on the global correlation network of the DEGs and DAMs,callose deposition that potentially adjusted symplastic flow in roots was almost independent of salinity in rootzones of Clipper,and was markedly decreased in Sahara.Taken together,we propose two distinctive salt tolerance mechanisms in Clipper(growth-sustaining)and Sahara(salt-shielding),providing important clues for improving crop plasticity to cope with deteriorating global soil salinization.
