棉花ARF因子的特征及GhARF2b在纤维发育中的作用

Characterization of cotton ARF factors and the role of GhARF2b in fiber development.

作者信息

Zhang Xiufang, Cao Junfeng, Huang Chaochen, Zheng Zishou, Liu Xia, Shangguan Xiaoxia, Wang Lingjian, Zhang Yugao, Chen Zhiwen

机构信息

National Key Laboratory of Plant Molecular Genetics and National Center for Plant Gene Research, Institute of Plant Physiology and Ecology/CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China.

Plant Stress Biology Center, Institute of Plant Physiology and Ecology/CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China.

出版信息

BMC Genomics. 2021 Mar 22;22(1):202. doi: 10.1186/s12864-021-07504-6.

BACKGROUND

Cotton fiber is a model system for studying plant cell development. At present, the functions of many transcription factors in cotton fiber development have been elucidated, however, the roles of auxin response factor (ARF) genes in cotton fiber development need be further explored.

RESULTS

Here, we identify auxin response factor (ARF) genes in three cotton species: the tetraploid upland cotton G. hirsutum, which has 73 ARF genes, and its putative extent parental diploids G. arboreum and G. raimondii, which have 36 and 35 ARFs, respectively. Ka and Ks analyses revealed that in G. hirsutum ARF genes have undergone asymmetric evolution in the two subgenomes. The cotton ARFs can be classified into four phylogenetic clades and are actively expressed in young tissues. We demonstrate that GhARF2b, a homolog of the Arabidopsis AtARF2, was preferentially expressed in developing ovules and fibers. Overexpression of GhARF2b by a fiber specific promoter inhibited fiber cell elongation but promoted initiation and, conversely, its downregulation by RNAi resulted in fewer but longer fiber. We show that GhARF2b directly interacts with GhHOX3 and represses the transcriptional activity of GhHOX3 on target genes.

CONCLUSION

Our results uncover an important role of the ARF factor in modulating cotton fiber development at the early stage.

背景

棉纤维是研究植物细胞发育的模式系统。目前，许多转录因子在棉纤维发育中的功能已得到阐明，然而，生长素响应因子（ARF）基因在棉纤维发育中的作用仍有待进一步探索。

结果

在此，我们在三种棉花中鉴定出生长素响应因子（ARF）基因：四倍体陆地棉（G. hirsutum）有73个ARF基因，其假定的亲本二倍体亚洲棉（G. arboreum）和雷蒙德氏棉（G. raimondii）分别有36个和35个ARF基因。Ka和Ks分析表明，在陆地棉中，ARF基因在两个亚基因组中经历了不对称进化。棉花ARF可分为四个系统发育分支，并在幼嫩组织中活跃表达。我们证明，拟南芥AtARF2的同源物GhARF2b在发育中的胚珠和纤维中优先表达。通过纤维特异性启动子过表达GhARF2b会抑制纤维细胞伸长，但促进其起始，相反，通过RNAi下调GhARF2b会导致纤维数量减少但长度增加。我们表明，GhARF2b直接与GhHOX3相互作用，并抑制GhHOX3对靶基因的转录活性。