Zhu Ziguo, Quan Ran, Chen Guangxia, Yu Guanghui, Li Xiujie, Han Zhen, Xu Wenwen, Li Guirong, Shi Jiangli, Li Bo
Shandong Academy of Grape, Shandong Academy of Agricultural Science, Jinan, China.
College of Horticulture and Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China.
Front Plant Sci. 2022 Sep 8;13:966641. doi: 10.3389/fpls.2022.966641. eCollection 2022.
In grapevines, the MYB transcription factors play an important regulatory role in the phenylpropanoid pathway including proanthocyanidin, anthocyanin, and flavonoid biosynthesis. However, the role of MYB in abiotic stresses is not clear. In this study, an R2R3-MYB transcription factor, , was isolated from a high drought-tolerant Chinese wild species . Our findings demonstrated that it was involved in plant development and drought tolerance. is a nuclear protein and is significantly induced by drought stress. When over-expressed in tobacco, caused plant dwarfing including plant height, leaf area, flower size, and seed weight. The GA1+3 content in transgenic plants was reduced significantly, and spraying exogenous gibberellin could recover the dwarf phenotype of transgenic plants, suggesting that might inhibit plant development by the regulation of gibberellin (GA) metabolism. Under drought stress, the transgenic plants improved their tolerance to drought with a lower wilting rate, lower relative electrical conductivity, and stronger roots. Compared to wild-type tobacco plants, transgenic plants accumulated less reactive oxygen, accompanied by increased antioxidant enzyme activity and upregulated gene expression levels of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) genes. In addition, transgenic plants accumulated more proline, and their related synthetic genes and genes were significantly upregulated when exposed to drought. Besides, abiotic stress-responsive genes, , and , were upregulated significantly in transgenic plants. These results indicate that plays a positive regulatory role in response to drought stress and also regulates plant development, which provides new evidence to further explore the molecular mechanism of drought stress of the MYB gene family.
在葡萄中，MYB转录因子在包括原花青素、花青素和类黄酮生物合成在内的苯丙烷途径中发挥着重要的调控作用。然而，MYB在非生物胁迫中的作用尚不清楚。在本研究中，从一种高度耐旱的中国野生种中分离出一个R2R3-MYB转录因子。我们的研究结果表明，它参与植物发育和耐旱性。是一种核蛋白，受干旱胁迫显著诱导。在烟草中过表达时，导致植物矮化，包括株高、叶面积、花大小和种子重量。转基因植物中的GA1+3含量显著降低，喷洒外源赤霉素可恢复转基因植物的矮化表型，表明可能通过调节赤霉素（GA）代谢来抑制植物发育。在干旱胁迫下，转基因植物提高了对干旱的耐受性，萎蔫率更低，相对电导率更低，根系更强。与野生型烟草植株相比，转基因植物积累的活性氧更少，同时抗氧化酶活性增加，超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）基因的表达水平上调。此外，转基因植物积累了更多的脯氨酸，在干旱条件下，其相关合成基因和基因显著上调。此外，非生物胁迫响应基因、和在转基因植物中显著上调。这些结果表明，在响应干旱胁迫中发挥正调控作用，同时也调节植物发育，这为进一步探索MYB基因家族干旱胁迫的分子机制提供了新的证据。
