MYB56 encoding a R2R3 MYB transcription factor regulates seed size in Arabidopsis thaliana.
MYB56 encoding a R2R3 MYB transcription factor regulates seed size in Arabidopsis thaliana.
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DOI：
10.1111/jipb.12094
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发表时间：
2013-11
影响因子：
11.4
通讯作者：
Yanjie Zhang;W. Liang;Jianxin Shi;Jie Xu;Dabing Zhang
中科院分区：
文献类型：
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作者：
Yanjie Zhang;W. Liang;Jianxin Shi;Jie Xu;Dabing Zhang
植物种子的大小受种皮、胚和胚乳发育的严格调控；然而，目前其潜在机制尚不清楚。在这项研究中，我们揭示了R2R3 MYB转录因子MYB56在控制拟南芥种子大小方面的调节作用，特别是在拟南芥中。与野生型相比，MYB56的功能丧失或敲除会产生更小的种子。相反，MYB56过表达产生较大的种子。半薄切片进一步观察发现，在种子发育过程中，myb56种皮外被层内皮细胞收缩变小，细胞数量减少；而MYB56过表达细胞系种皮外被层内皮细胞扩增，细胞数量增加，表明MYB56在调节种子发育中起重要作用。此外，互易交叉分析表明MYB56对种子母系发育有影响。MYB56在种子发育中主要表达，与其在种子发育中的功能一致。此外，定量逆转录聚合酶链反应分析显示，MYB56调控细胞壁代谢（如细胞分裂和扩增）相关基因的表达。总之，我们的研究结果表明MYB56代表了一种未知的积极控制种子大小的途径。
Plant seed size is tightly regulated by the development of seed coat, embryo, and endosperm; however, currently, its underlying mechanism remains unclear. In this study, we revealed a regulatory role of an R2R3 MYB transcription factor MYB56 in controlling seed size specifically in Arabidopsis thaliana L. Loss-of-function or knock-down of MYB56 yielded smaller seeds as compared with the wild type. Conversely, overexpression of MYB56 produced larger seeds. Further observation using semi-thin sections showed that myb56 developed smaller contracted endothelial cells and reduced cell number in the outer integument layer of the seed coat during the seed development; by contrast, MYB56 overexpressing lines had expanded endothelial cells and increased cell number in the outer integument layer of the seed coat, suggesting the essential role of MYB56 in regulating seed development. In addition, reciprocal cross-analysis showed that MYB56 affected the seed development maternally. MYB56 was shown to be dominantly expressed in developing seeds, consistently with its function in seed development. Moreover, quantitative reverse transcription polymerase chain reaction analysis revealed that MYB56 regulates the expression of genes involved in cell wall metabolism such as cell division and expansion. Altogether, our results demonstrated that MYB56 represents an unknown pathway for positively controlling the seed size.