National Key Laboratory of Cotton Bio‑breeding and Integrated Utilization, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China; State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
National Key Laboratory of Cotton Bio‑breeding and Integrated Utilization, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China.
J Adv Res. 2024 Jul;61:1-17. doi: 10.1016/j.jare.2023.08.017. Epub 2023 Aug 28.
Sessile plants engage in trade-offs between growth and defense capacity in response to fluctuating environmental cues. MYB is an important transcription factor that plays many important roles in controlling plant growth and defense. However, the mechanism behind how it keeps a balance between these two physiological processes is still largely unknown.
Our work focuses on the dissection of the molecular mechanism by which GhMYB33 regulates plant growth and defense.
The CRISPR/Cas9 technique was used to generate mutants for deciphering GhMYB33 functions. Yeast two-hybrid, luciferase complementary imaging, and co-immunoprecipitation assays were used to prove that proteins interact with each other. We used the electrophoretic mobility shift assay, yeast one-hybrid, and luciferase activity assays to analyze GhMYB33 acting as a promoter. A β-glucuronidase fusion reporter and 5' RNA ligase mediated amplification of cDNA ends analysis showed that ghr-miR319c directedly cleaved the GhMYB33 mRNA.
Overexpressing miR319c-resistant GhMYB33 (rGhMYB33) promoted plant growth, accompanied by a significant decline in resistance against Verticillium dahliae. Conversely, its knockout mutant, ghmyb33, demonstrated growth restriction and concomitant augmentation of V. dahliae resistance. GhMYB33 was found to couple with the DELLA protein GhGAI1 and bind to the specific cis-elements of GhSPL9 and GhDFR1 promoters, thereby modulating internode elongation and plant resistance in V. dahliae infection. The ghr-miR319c was discovered to target and suppress GhMYB33 expression. The overexpression of ghr-miR319c led to enhanced plant resistance and a simultaneous reduction in plant height.
Our findings demonstrate that GhMYB33 encodes a hub protein and controls the expression of GhSPL9 and GhDFR1, implicating a pivotal role for the miR319c-MYB33 module to regulate the trade-offs between plant growth and defense.
固着植物会根据环境信号的波动，在生长和防御能力之间进行权衡。MYB 是一种重要的转录因子，在控制植物生长和防御方面发挥着许多重要作用。然而，它如何在这两个生理过程之间保持平衡的机制在很大程度上仍然未知。
我们的工作重点是解析 GhMYB33 调节植物生长和防御的分子机制。
使用 CRISPR/Cas9 技术生成突变体以破译 GhMYB33 功能。酵母双杂交、荧光素酶互补成像和共免疫沉淀实验用于证明蛋白质相互作用。我们使用电泳迁移率变动分析、酵母单杂交和荧光素酶活性测定分析 GhMYB33 作为启动子的作用。β-葡萄糖醛酸酶融合报告基因和 5' RNA 连接酶介导的 cDNA 末端扩增分析表明，ghr-miR319c 可以直接切割 GhMYB33 mRNA。
过表达 miR319c 抗性的 GhMYB33(rGhMYB33)促进了植物生长，同时显著降低了对黄萎病菌的抗性。相反，其敲除突变体 ghmyb33 表现出生长受限和黄萎病菌抗性增强。发现 GhMYB33 与 DELLA 蛋白 GhGAI1 结合，并与 GhSPL9 和 GhDFR1 启动子的特定顺式元件结合，从而调节节间伸长和黄萎病菌感染下的植物抗性。发现 ghr-miR319c 靶向并抑制 GhMYB33 的表达。ghr-miR319c 的过表达导致植物抗性增强，同时植株高度降低。
我们的研究结果表明，GhMYB33 编码一种枢纽蛋白，调控 GhSPL9 和 GhDFR1 的表达，表明 miR319c-MYB33 模块在调节植物生长和防御之间的权衡中起着关键作用。
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