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The transcription factor γMYB2 acts as a negative regulator of secondary cell wall thickening in anther and stem
- Nguyen, Ha Thi Kim, Hyoung, Sujin, Kim, Hae Jin, Cho, Kwang Moon, Shin, Jeong Sheop
- Gene 2019 v.702 pp. 158-165
- Arabidopsis, anthers, cell walls, cellulose, dehiscence, forces, fruits, gene overexpression, genes, male sterility, phenotype, transcription factors, xylem
- Secondary cell wall (SCW) thickening provides the mechanical force for anther dehiscence and plays an important role in the formation of xylem structure. We have previously reported that γMYB2, a MYB coiled-coil protein, directly binds to the P1BS cis-element of the PLA2-γ promoter and acts as a co-activator of γMYB1 in controlling the expression of PLA2-γ. In this study, we analyzed morphological phenotypes of the constitutive overexpression (γMYB2-OE) and knock-down (γMYB2-KD) lines of γMYB2. We found that γMYB2 overexpression caused the collapse of the endothecium layer, thereby suppressing anther dehiscence and forming short infertile siliques. The γMYB2-OE also showed less cellulose deposition in the xylem and had a longer primary stem than the wild-type, while γMYB2-KD had greater cellulose accumulation and a shorter primary stem than the wild-type. We demonstrated that the male sterility and the longer primary stem in γMYB2-OE were caused by reduced expression of SCW thickening-related genes. Our results suggest that γMYB2 acts as a negative regulator in controlling the SCW thickening in Arabidopsis.