miR828 and miR858 regulate homoeologous MYB2 gene functions in Arabidopsis trichome and cotton fibre development
miR828 and miR858 regulate homoeologous MYB2 gene functions in Arabidopsis trichome and cotton fibre development
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DOI：
10.1038/ncomms4050
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发表时间：
2014-01-01
影响因子：
16.6
通讯作者：
Chen, Z. Jeffrey
中科院分区：
文献类型：
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作者：
Guan, Xueying;Pang, Mingxiong;Chen, Z. Jeffrey
虽然多倍体在植物和一些动物中很常见，但同源异型基因之间的功能分歧机制知之甚少。MYB 2基因促进棉花纤维发育，与拟南芥GLABROUS 1（GL 1）在毛状体形成中功能同源。最广泛种植的棉花是含有GhMYB 2A和GhMYB 2D同源物的异源四倍体（陆地棉，AADD）。在这里，我们发现GhMYB 2D mRNA在纤维起始过程中比GhMYB 2A积累更多，并被miR 828和miR 858靶向，在TAS 4家族中产生反式作用siRNA（ta-siRNA）。过度表达GhMYB 2A而不是GhMYB 2D补充了gl 1表型。突变miR 828结合位点或替换GhMYB 2D中的下游序列可消除ta-siRNA的产生并恢复gl 1突变体中的毛状体发育。此外，破坏Gl 1 GhMYB 2D过表达体中的Ta-siRNA的生物发生基因Dicer样蛋白4或RDR 6，恢复毛状体发育。这些数据支持microRNA在目标同源异型基因之间的功能分歧中的独特作用，这些基因对形态性状的进化和选择很重要。
Although polyploidy is common in plants and some animals, mechanisms for functional divergence between homoeologous genes are poorly understood. MYB2 gene promotes cotton fibre development and is functionally homologous to Arabidopsis GLABROUS1 (GL1) in trichome formation. The most widely cultivated cotton is an allotetraploid (Gossypium hirsutum, AADD) that contains GhMYB2A and GhMYB2D homoeologs. Here we show that GhMYB2D mRNA accumulates more than GhMYB2A during fibre initiation and is targeted by miR828 and miR858, generating trans-acting siRNAs (ta-siRNAs) in the TAS4 family. Over-expressing GhMYB2A but not GhMYB2D complements the gl1 phenotype. Mutating the miR828-binding site or replacing its downstream sequence in GhMYB2D abolishes ta-siRNA production and restores trichome development in gl1 mutants. Moreover, disrupting Dicer-like protein 4 or RDR6, the biogenesis genes for ta-siRNAs, in the gl1 GhMYB2D overexpressors restores trichome development. These data support a unique role for microRNAs in functional divergence between target homoeologous genes that are important for evolution and selection of morphological traits.