陆地棉XTH基因家族全基因组鉴定及在纤维发育过程的表达分析

本研究从陆地棉TM-1基因组中鉴定出72个XTH家族基因,编码木葡聚糖内转糖苷酶/水解酶(XTH,xyloglucan endotransglycosylase/hydrolase),分别命名为Gh XTH01~Gh XTH72,分析了其基因结构、保守基序、系统进化、理化性质、亚细胞定位,并探究其在棉纤维发育不同时期的表达规律。结果表明,XTH家族基因分布在除At 07、Dt 07以外的24条棉花染色体上,根据系统发育树,将XTH家族基因分为3个亚组;XTH氨基酸序列有3个保守基序,保守性较强;多数XTH蛋白定位在细胞外。根据XTHs在纤维发育不同时期的表达量变化,将其分为4类。通过构建陆地棉与拟南芥XTH氨基酸序列进化树,推测Gh XTH15、Gh XTH28、Gh XTH36、Gh XTH49、Gh XTH59、Gh XTH62、Gh XTH63等基因在棉纤维发育过程中发挥重要作用。通过比较XTH家族基因在不同纤维品质陆地棉品种中的表达差异,推测在优质棉花品种中优势表达基因Gh XTH03、Gh XTH12、Gh XTH17、Gh XTH22、Gh XTH23、Gh XTH28、Gh XTH33、Gh XTH44、Gh XTH46、Gh XTH59等在纤维发育伸长过程中可能发挥着重要作用。上述结果为研究陆地棉XTH基因家族在棉纤维发育中的功能提供了参考依据。

Genome-wide Identification and Expression Analysis of the XTH Gene Family in Fiber Development Process in Gossypium hirsutum L.

In this study,72 XTH genes encoded xyloglucan endotransglycosylase/hydrolase were identified in the Gossypium hirsutum L.genome and named GhXTH1-GhXTH72.Their physicochemical properties,subcellular location,gene structure,gene evolutionary and conservative motif of the amino acid sequences were analyzed,and expression pattems in different fiber development stages were explored.The results showed that the predicted XTH genes of cotton were distributed across 24 chromosomes except for At 07 and Dt 07.XTHs were classified into three subgroups according to the phylogenic relationship and gene structure.XTHs had three highly conserved motifs and most of XTHs exsited in extracellular.Moreover,the expressions of all the cotton XTH genes were analyzed in different fiber developmental stages.According to the change of the XTHs expression in different stages of fiber development,it was divided into four profiles.GhXTH15,GhXTH28,GhXTH36,GhXTH49,GhXTH59,GhXTH62,GhXTH63 etc.played important roles in the fiber development by constructing the phylogenetic tree of the amino acid sequences of the Arabidopsis thaliana L.and the upland cotton.The dominant expression genes including GhXTH03,GhXTH12,GhXTH17,GhXTH22,GhXTH23,GhXTH28,GhXTH33,GhXTH44,GhXTH46,GhXTH59 might play an important role in fiber elongation stage by comparing gene expression of XTH gene family in upland cottons with different fiber qualities.The above analysis provided a useful reference for the further validation of the XTH gene family in the development of fiber in Gossypium hirsutum L..