雷蒙德氏棉HSP70基因家族的进化分析及其同源基因在陆地棉中的表达分析

热激蛋白70家族(HSP70)是一类在植物中高度保守的分子伴侣蛋白,在细胞中协助蛋白质正确折叠。文章利用隐马可链夫模型(HMM)在雷蒙德氏棉(Gossypium raimondii L.)全基因组范围内进行HSP70基因家族成员进化分析,共得到30个HSP70家族成员。利用生物信息学对雷蒙德氏棉HSP70基因的结构、染色体分布、基因倍增模式以及系统进化进行分析,结果表明,HSP70基因家族根据亚细胞定位结果可分为不同的基因亚家族,各亚家族中HSP70基因具有相对保守的基因结构;染色体片段重复和串联重复是雷蒙德氏棉HSP70基因家族扩增的主要方式。通过对不同物种的HSP70基因家族进行系统进化分析可知,HSP70亚组的分化发生在单细胞植物形成前,且细胞质型HSP70成员大量扩增。比较陆地棉棉纤维发育不同时期的深度测序表达谱,发现HSP70基因可能参与棉纤维的生长发育。本研究结果有助于了解棉属植物HSP70基因家族的功能,以期为深入研究棉纤维发育过程中的分子调控机理提供基础。

Genome-wide analysis of HSP70 superfamily in Gossypium raimondii and the expression of orthologs in Gossypium hirsutum

Heat shock 70 (HSP70) proteins are highly conserved molecular chaperones widely existed in the plant kingdom which are involved in cellular protein folding process. In this study, comprehensive evolutionary analyses of the Gossypium raimondii HSP70 gene family members are conducted and 30 HSP70 genes are identified. The gene structure, chromosome distribution, gene duplication and phylogenic evolution of this family are further analyzed. The results reveal that HSP70 family genes can be clustered into several major subgroups based on their sub-cellular locations, and the gene structures are relatively conserved in each subgroup. Both tandem duplications and chromosome segmental duplications are found to contribute to the expansion of HSP70 gene family. Evolutionary analysis of HSP70s in diverse species reveals that the differentiation of HSP70 subgroups occurred before the multi-cell and single-cell differentiation, with the cytoplasmic HSP70s multiple amplified. The expression pattern of HSP70 genes under series of fiber development stages indicates that many HSP70 genes may participate in fiber development processes including fiber initiation and elongation. This study provides the complete profiles of cotton HSP70 family genes for future study on their functions related to the molecular mechanisms of fiber development.