Zhai Kaihui, Zhao Guangwu, Jiang Hongye, Sun Caixia, Ren Jingyu
The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Agriculture and Food Science, Zhejiang Agriculture and Forestry University, Hangzhou, China.
Front Plant Sci. 2020 Sep 11;11:564665. doi: 10.3389/fpls.2020.564665. eCollection 2020.
MYB transcription factors are involved in many biological processes, including metabolism, stress response and plant development. In our previous work, was down-regulated by deep sowing during maize seed germination. However, there are few reports on seed germination regulated by MYB proteins. In this study, to examine its functions during seed germination, -mediated transformation was exploited to generate overexpression (OE) tobacco and rice. In T generation transgenic tobacco, germination rate, germination index, vigor index and hypocotyl length were significantly decreased by 25.0-50.9, 34.5-54.4, 57.5-88.3, and 21.9-31.3% compared to wild-type (WT) lines. In T generation transgenic rice, above corresponding parameters were notably reduced by 39.1-53.8, 51.4-71.4, 52.5-74.0, and 28.3-41.5%, respectively. On this basis, antioxidant capacity and endogenous hormones were determined. The activities of catalase, peroxidase, superoxide dismutase, ascorbate peroxidase of OE lines were significantly lower than those of WT, suggesting that reduced their oxidation resistance. As well, overexpression extremely inhibited the synthesis of gibberellin A1 (GA) and cytokinin (CTK), and promoted the synthesis of abscisic acid (ABA) concurrently. Taken together, it proposed that ZmMYB59 was a negative regulator during seed germination in tobacco and rice, which also contributes to illuminate the molecular mechanisms regulated by MYB transcription factors.
MYB转录因子参与许多生物学过程，包括新陈代谢、应激反应和植物发育。在我们之前的研究中，玉米种子萌发期间深播会下调该基因。然而，关于MYB蛋白调控种子萌发的报道很少。在本研究中，为了研究其在种子萌发过程中的功能，利用基因介导的转化方法获得了过表达（OE）的烟草和水稻。在T代转基因烟草中，与野生型（WT）植株相比，发芽率、发芽指数、活力指数和下胚轴长度分别显著降低了25.0 - 50.9%、34.5 - 54.4%、57.5 - 88.3%和21.9 - 31.3%。在T代转基因水稻中，上述相应参数分别显著降低了39.1 - 53.8%、51.4 - 71.4%、52.5 - 74.0%和28.3 - 41.5%。在此基础上，测定了抗氧化能力和内源激素。OE株系的过氧化氢酶、过氧化物酶、超氧化物歧化酶、抗坏血酸过氧化物酶活性均显著低于野生型，表明该基因降低了它们的抗氧化能力。此外，该基因的过表达极大地抑制了赤霉素A1（GA）和细胞分裂素（CTK）的合成，同时促进了脱落酸（ABA）的合成。综上所述，推测ZmMYB59是烟草和水稻种子萌发过程中的负调控因子，这也有助于阐明MYB转录因子调控的分子机制。
