Evolution of pectin synthesis relevant galacturonosyltransferase gene family and its expression during cotton fiber development

摘要

Background:Pectin is a key substance involved in cell wall development,and the galacturonosyltransferases(GAUTs)gene family is a critical participant in the pectin synthesis pathway.Systematic and comprehensive research on GAUTs has not been performed in cotton.Analysis of the evolution and expression patterns of the GAUT gene family in different cotton species is needed to in crease kno wledge of the functi on of pectin in cotto n fiber development.Results:In this study,we have identified 131 GAUT genes in the genomes of four Gossypium species(G.raimondii,G barbadense,G.hirsutum,and G.arboreum),and classified them as GAUT-A,GAUT-B and GAUT-C,which coding probable galacturonosyltransferases.Among them,the GAUT genes encode proteins GAUT1 to GAUT15.All GAUT proteins except for GAUT7 contai n a con served glycosyl transferase family 8 domain(H-DN-A-SW-S-V-H-T-F).The conserved sequence of GAUT7 is PLN(phospholamban)02769 domain.According to c/s-elemet analysis,GAUT genes transcript levels may be regulated by horm ones such as JA,GA,SA,ABA,Me-JA,and IA A.The evoluti on and transcription patterns of the GAUT gene family in different cotton species and the transcript levels in upland cotton lines with different fiber st「ength were analyzed.Peak transcript level of GhGAUT genes have been observed before 15 DPA.In the six materials with high fiber strength,the transcription of GhGAUT genes were concentrated from 10 to 15 DPA;while the highest transcript levels in low fiber st「ength materials were detected between 5 and 10 DPA.These results lays the foundation for future research on gene function during cotton fiber development.Conclusions:The GAUT gene family may affect cotton fiber development,including fiber elongation and fiber thickening.In the low strength fiber lines,GAUTs mainly participate in fiber elongation,whereas their major effect on cotton with high strength fiber is related to both elongation and thickening.