Genome-Wide Identification of R2R3-MYB Transcription Factors Regulating Secondary Cell Wall Thickening in Cotton Fiber Development
Genome-Wide Identification of R2R3-MYB Transcription Factors Regulating Secondary Cell Wall Thickening in Cotton Fiber Development
复制标题
全基因组鉴定调节棉纤维发育中次生细胞壁增厚的 R2R3-MYB 转录因子
DOI：
10.1093/pcp/pcy238
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发表时间：
2019-03-01
影响因子：
4.9
通讯作者：
Xu, Wenliang
中科院分区：
文献类型：
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作者：
Huang, Junfeng;Guo, Yanjun;Xu, Wenliang
MYB蛋白是植物中最大的转录因子家族之一，其中一些是次生细胞壁生物合成的关键转录调节因子。棉花纤维被认为是研究细胞伸长和SCW生物合成的理想单细胞模型。然而，关于TFS控制纤维SCW生物合成的知识很少，特别是对于R2R3-MYB。到目前为止，还没有关于栽培四倍体陆地棉中与次生壁相关的R2R3-MYB的全面全基因组分析的报道。在本研究中，我们通过系统研究棉花基因组，鉴定了419个R2R3-MYB基因。系统发育、RNA-seq和共表达分析表明，36个R2R3-MYB在花后20天的纤维中优先或高表达，可能是SCW调节因子。在这些MYB基因中，22个MYB是已知SCW MYB蛋白的同源物，另外14个MYB是新的蛋白质，没有先前报道的与SCW生物合成相关的功能。最后，我们重点介绍了GhMYB46_D13和GhMYB46_D9这两个MYB的作用，这两个MYB在20dpa纤维中表达最高。GhMYB46_D13或GhMYB46_D9分别在拟南芥中的表达导致转基因植株中SCW的异位沉积。此外，GhMYB46_D13和GhMYB46_D9均能激活棉纤维SCW纤维素合成酶基因启动子。因此，我们已经确定了36个R2R3-MYB作为棉纤维中潜在的SCW调节因子，它们代表了进一步研究纤维发育和SCW加厚过程中的功能的有力候选者。
MYB proteins represent one of the largest transcription factor (TF) families in plants, some of which act as key transcriptional regulators of secondary cell wall (SCW) biosynthesis. Cotton (Gossypium hirsutum) fiber is thought to be an ideal single-cell model to study cell elongation and SCW biosynthesis. However, little knowledge regarding the TFs controlling fiber SCW biosynthesis, particularly for R2R3-MYBs is known. By far, no comprehensive genome-wide analysis of the secondary wall-associated R2R3-MYBs has been reported in cultivated tetraploid upland cotton. In this study, we identified 419 R2R3-MYB genes by systematically examining the cotton genome. A combination of phylogenetic, RNA-seq and co-expression analyses indicated that 36 R2R3-MYBs were either preferentially or highly expressed in 20 day post anthesis (dpa) fibers and are putative SCW regulators. Among these MYB genes, 22 MYBs are homologs of known SCW MYB proteins and the other 14 MYBs are novel proteins without prior reported SCW biosynthesis-related functions. Finally, we highlighted on the roles of two MYBs named GhMYB46_D13 and GhMYB46_D9, both of which displayed the highest expression in 20 dpa fibers. Expression of GhMYB46_D13 or GhMYB46_D9 individually in Arabidopsis resulted in ectopic SCW deposition in transgenic plants. Furthermore, both GhMYB46_D13 and GhMYB46_D9 were able to activate the cotton fiber SCW cellulose synthase gene promoters. Thus, we have identified 36 R2R3-MYBs as potential SCW regulators in cotton fibers that represent strong candidates for further functional studies during fiber development and SCW thickening.