敲除1个基因,实现广谱抗病,华中农业大学在《Plant Journal》发表研究论文揭示番茄广谱抗病的新机制

近日，华中农业大学园艺林学学院、果蔬园艺作物种质创新与利用全国重点实验室王涛涛教授课题组在The Plant Journal在线发表题为“The SlSRC2-SlMLP1 module regulates broad-spectrum disease resistance by activating steroidal glycoalkaloid biosynthesis in tomato”的研究论文。该研究发现，番茄免疫负调控因子SlSRC2通过抑制SlMLP1入核，拮抗调节SlERF2a的蛋白丰度，从而调控生物碱的生物合成，提高对多种病害的抗性；揭示了SlSRC2-SlMLP1模块拮抗调控番茄广谱抗病的分子机制。

随着番茄种植面积的不断扩大，番茄经常受到各类病原菌的威胁，导致其产量和品质遭受严重损失。因此，研究番茄广谱抗病分子机理，培育广谱抗性的番茄种质是生产中亟待解决的痛点。

本研究发现，编码C2蛋白的SlSRC2能够负调控番茄对灰霉病、晚疫病以及黄化曲叶病毒病的抗性，而其互作蛋白SlMLP1能够正调控番茄的广谱抗性。研究人员进一步通过LCI试验筛选SlMLP1的互作蛋白SlERF2a。该转录因子抑制甾体糖苷生物碱合成途径结构基因SlGAME12的转录表达。

SlSRC2–SlMLP1模块调控番茄广谱抗病的机理模式图

此外，通过酵母双杂筛库发现，SlMLP1能够结合两个蛋白降解因子SlPSMC6A/SlSGTA，该降解因子通过26S蛋白酶体途径降解SlMLP1-SlERF2a蛋白复合体，导致SlGAME12的转录抑制被解除，生物碱积累显著增多，植株抗性增强。而SlSRC2通过抑制SlMLP1的核定位，间接维持SlERF2a的蛋白丰度，导致植株体内生物碱的积累减弱，植株表现为感病。本研究解析了SlSRC2-SlMLP1蛋白模块介导的番茄广谱抗病的分子机理，完善番茄对广谱病原菌的防御机制。

华中农业大学园艺林学学院博士研究生聂立兵为该论文第一作者，蔬菜系王涛涛教授为通讯作者。已毕业博士生孙文慧、山西农业大学园艺学院罗丹副教授等参与了研究工作。该研究得到国家重点研发计划、国家自然科学基金等项目的资助。

【英文摘要】

Global tomato production faces persistent threats from various pathogens, leading to substantial yield and quality losses. Cultivating tomato varieties with broad-spectrum disease resistance (BSR) is therefore a crucial objective for sustainable agriculture. Here, we identified a molecular module centered on the antagonistic regulation between SlSRC2 and SlMLP1, which coordinates BSR against multiple pathogens, including Botrytis cinerea, Phytophthora infestans, and tomato yellow leaf curl virus. SlSRC2 functions as a negative regulator by interacting with and suppressing the nuclear localization of the positive regulator SlMLP1. Both SlMLP1 and SlSRC2 converge on the transcription factor SlERF2a, where they antagonistically modulate its transcriptional activity to regulate the expression of SlGAME12, a key biosynthetic gene for steroidal glycoalkaloids (SGAs). Furthermore, we elucidated that the degradation factors SlPSMC6A and SlSGTA interact with SlMLP1 to mediate the degradation of the SlMLP1-SlERF2a complex and enhance BSR. This degradation relieves SlERF2a-mediated repression of SlGAME12, ultimately promoting SGAs accumulation and thereby boosting plant immunity. Collectively, our findings reveal a novel molecular mechanism by which the SlSRC2-SlMLP1 module regulates BSR in tomato through modulating SGAs biosynthesis, while also providing valuable genetic resources for the breeding of BSR tomato varieties.

论文链接：https://doi.org/10.1111/tpj.70933