关键词: 海岛棉, GH9基因家族, 进化, 表达分析, 棉纤维发育

Abstract: GH9 genes play  vital roles in the biosynthesis and remodeling of plant cell walls. The aim of this study was to discover fiber development-related GH9 genes by the identification and analysis of this gene family in Gossypium barbadense. A total of 53 GH9 genes were identified from Gossypium barbadense, and their physico-chemical properties, gene structure, chromosomal distribution and evolutionary history were analyzed. This paper also investigated the expression patterns and transcriptional regulation of GbGH9s during cotton fiber development. As a result, 53 GbGH9s were divided into three groups (A, B and C) and were distributed on 22 chromosomes. The expansion of GH9 gene family was mainly driven by polyploidization in Gossypium barbadense, and the duplicated genes had been under strong selective constraints. Some members of group A showed high expression levels during cotton fiber development, especially during secondary wall thickening. Some members of group C were highly expressed during cotton fiber initiation and elongation. In addition, the expression patterns of group B were relatively complex. Auxin and ethylene may have played important roles in the transcriptional regulation of GbGH9s. It improved cotton fiber strength by the introgression of GbGH9B6 into Gossypium hirsutum. The identification and analysis of GbGH9s were critical for understanding their evolution and functions, and provided a support for future studies.

Key words: Gossypium barbadense, GH9 gene family, evolution, expression analysis, cotton fiber development