MYB56 Encoding a R2R3 MYB Transcription Factor Regulates Seed Size in Arabidopsis thaliana

• Published in: Journal of integrative plant biology Vol. 55; no. 11; pp. 1166 - 1178
• Main Authors: Zhang, Yanjie, Liang, Wanqi, Shi, Jianxin, Xu, Jie, Zhang, Dabing
• Format: Journal Article
• Language: English
• Published: China (Republic : 1949- ) Blackwell Publishing Ltd 01.11.2013; School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
• Subjects: Arabidopsis - anatomy & histology; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Cell Proliferation; Cell wall; Cell Wall - genetics; Cotyledon - genetics; Cotyledon - growth & development; Endothelial Cells - cytology; endothelium; Gene Expression Regulation, Developmental; Gene Expression Regulation, Plant; Gene Knockdown Techniques; Gene Knockout Techniques; Genes, Plant; MYB; MYB转录因子; seed coat; seed size; Seeds - anatomy & histology; Seeds - genetics; Seeds - growth & development; Seeds - metabolism; Time Factors; Transcription Factors - genetics; Transcription Factors - metabolism; 发育过程; 拟南芥属; 种子大小; 编码; 血管内皮细胞; 调控; 过量表达; endothelium; Cell wall; seed coat; MYB; seed size
• ISSN: 1672-9072; 1744-7909
• DOI: 10.1111/jipb.12094

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.