图1 SlBBX20负调控番茄对灰霉病的抗性

图2 SlBBX20 通过抑制SlMED25蛋白的积累调控JA信号影响对灰霉病的抗性

南湖新闻网讯（通讯员 罗丹）灰葡萄孢菌（Botrytis cinerea）是一种腐生型的真菌，可侵染包括番茄、草莓和黄瓜等二百多种植物，严重威胁植物的生长和发育。目前生产上主要通过喷施农药进行防治，但防治效果并不理想而且会影响果蔬品质，危害环境安全。因此，研究番茄对灰霉病的抗病机制，克隆抗灰霉病的基因，培育抗灰霉病的番茄品种非常重要。

近日，我校园艺林学学院番茄团队王涛涛教授课题组在Plant Biotechnology Journal发表了题为“SlBBX20 attenuates JA signaling and regulates resistance to Botrytis cinerea by inhibiting SlMED25 in tomato”的研究论文。茉莉酸(JA)在调节植物生长和防御反应中发挥着重要作用，研究发现SlBBX20可调控JA的各种响应反应，是一个新的JA响应的负调控因子，JA与灰霉病的抗性密切相关，当过量表达SlBBX20时，番茄对茉莉酸的响应被抑制，导致番茄对灰霉病的抗性减弱。相反，当敲除SlBBX20基因后，JA响应增强，同时显著增强了番茄对灰霉病的抗性。

进一步研究发现SlBBX20与介导转录激活复合物的亚基SlMED25相互作用，并阻止SlMED25蛋白的积累和JA应答基因的转录。JA有助于增强植物对坏死性病原体的防御反应，超量表达SlMED25增强了番茄对灰霉病的抗性。当在超量表达SlMED25的植物中进一步超量表达SlBBX20时，番茄对灰霉病的抗性减弱了，如果敲除SlBBX20时，抗性又恢复了。这些数据表明SlBBX20通过调节 SlMED25来减弱JA信号传导，进而影响番茄对灰霉病的抗性。有趣的是，SlBBX20敲除植株不仅增强了番茄对灰霉病的抗性，也提高了番茄果实的产量。SlBBX20将是一个利用基因编辑技术开发既抗病又高产品种的潜在目标基因。

华中农业大学园艺林学学院博士毕业生罗丹为该论文的第一作者，王涛涛教授为论文通讯作者。叶志彪教授，张俊红教授，杨长宪教授，Robert M. Larkin教授参与了该项研究，特别感谢王正明教授对文章的修改。该研究得到了国家自然科学基金、国家重点研发计划和湖北省自然科学基金的资助。

英文摘要：

Jasmonic acid (JA) plays an important role in regulating plant growth and defense responses. Here, we show that a transcription factor that belongs to the B-box (BBX) family named SlBBX20 regulates resistance to Botrytis cinerea in tomato by modulating JA signaling. The response to JA was significantly suppressed when SlBBX20 was overexpressed in tomato. In contrast, the JA response was enhanced in SlBBX20 knockout lines. RNA sequencing analysis provided more evidence that SlBBX20 modulates the expression of genes that are involved in JA signaling. We found that SlBBX20 interacts with SlMED25, a subunit of the Mediator transcriptional co-activator complex, and prevents the accumulation of the SlMED25 protein and transcription of JA-responsive genes. JA contributes to the defense response against necrotrophic pathogens. Knocking out SlBBX20 or overexpressing SlMED25 enhanced tomato resistance to B. cinerea. The resistance was impaired when SlBBX20 was overexpressed in plants that also overexpressed SlMED25. These data show that SlBBX20 attenuates JA signaling by regulating SlMED25. Interestingly, in addition to developing enhanced resistance to B. cinerea, SlBBX20-KO plants also produced higher fruit yields. SlBBX20 is a potential target gene for efforts that aim to develop elite crop varieties using gene editing technologies.

原文链接：https://onlinelibrary.wiley.com/doi/abs/10.1111/pbi.13997

审核人：王涛涛