Marine and Agricultural Biotechnology Laboratory, Institute of Oceanography, Minjiang University, Fuzhou, 350108, China.
Biotechnology Research Institute, Fujian Academy of Agricultural Sciences, Fuzhou, 350003, China.
BMC Plant Biol. 2021 Feb 18;21(1):100. doi: 10.1186/s12870-021-02880-3.
Methyl-CpG-binding domain (MBD) proteins play important roles in epigenetic gene regulation, and have diverse molecular, cellular, and biological functions in plants. MBD proteins have been functionally characterized in various plant species, including Arabidopsis, wheat, maize, and tomato. In rice, 17 sequences were bioinformatically predicted as putative MBD proteins. However, very little is known regarding the function of MBD proteins in rice.
We explored the expression patterns of the rice OsMBD family genes and identified 13 OsMBDs with active expression in various rice tissues. We further characterized the function of a rice class I MBD protein OsMBD707, and demonstrated that OsMBD707 is constitutively expressed and localized in the nucleus. Transgenic rice overexpressing OsMBD707 displayed larger tiller angles and reduced photoperiod sensitivity-delayed flowering under short day (SD) and early flowering under long day (LD). RNA-seq analysis revealed that overexpression of OsMBD707 led to reduced photoperiod sensitivity in rice and to expression changes in flowering regulator genes in the Ehd1-Hd3a/RFT1 pathway.
The results of this study suggested that OsMBD707 plays important roles in rice growth and development, and should lead to further studies on the functions of OsMBD proteins in growth, development, or other molecular, cellular, and biological processes in rice.
甲基化 CpG 结合域（MBD）蛋白在表观遗传基因调控中发挥重要作用，在植物中具有多种分子、细胞和生物学功能。MBD 蛋白已在多种植物物种中得到功能表征，包括拟南芥、小麦、玉米和番茄。在水稻中，有 17 个序列被生物信息学预测为潜在的 MBD 蛋白。然而，对于 MBD 蛋白在水稻中的功能知之甚少。
我们探索了水稻 OsMBD 家族基因的表达模式，鉴定了 13 个在各种水稻组织中具有活性表达的 OsMBD。我们进一步表征了水稻 I 类 MBD 蛋白 OsMBD707 的功能，并证明 OsMBD707 组成性表达并定位于细胞核中。过表达 OsMBD707 的转基因水稻表现出更大的分蘖角度和对短日照（SD）下开花的光周期敏感性降低以及长日照（LD）下开花的提前。RNA-seq 分析表明，OsMBD707 的过表达导致水稻对光周期敏感性降低，以及 Ehd1-Hd3a/RFT1 途径中开花调节基因的表达变化。
本研究结果表明，OsMBD707 在水稻生长发育中发挥重要作用，应进一步研究 OsMBD 蛋白在水稻生长、发育或其他分子、细胞和生物学过程中的功能。
