Sun Bingxue, Zhou Rongjia, Zhu Guangxue, Xie Xuewen, Chai Ali, Li Lei, Fan Tengfei, Li Baoju, Shi Yanxia
State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Microorganisms. 2023 Nov 23;11(12):2849. doi: 10.3390/microorganisms11122849.
Quinone outside inhibitor fungicides (QoIs) are crucial fungicides for controlling plant diseases, but resistance, mainly caused by G143A, has been widely reported with the high and widespread use of QoIs. However, two phenotypes of (RI and RII) with the same G143A showed significantly different resistance to QoIs in our previous study, which did not match the reported mechanisms. Therefore, transcriptome analysis of RI and RII strains after trifloxystrobin treatment was used to explore the new resistance mechanism in this study. The results show that 332 differentially expressed genes (DEGs) were significantly up-regulated and 448 DEGs were significantly down-regulated. The results of GO and KEGG enrichment showed that DEGs were most enriched in ribosomes, while also having enrichment in peroxide, endocytosis, the lysosome, autophagy, and mitophagy. In particular, mitophagy and peroxisome have been reported in medicine as the main mechanisms of reactive oxygen species (ROS) scavenging, while the lysosome and endocytosis are an important organelle and physiological process, respectively, that assist mitophagy. The oxidative stress experiments showed that the oxidative stress resistance of the RII strains was significantly higher than that of the RI strains: specifically, it was more than 1.8-fold higher at a concentration of 0.12% H2O2. This indicates that there is indeed a significant difference in the scavenging capacity of ROS between the two phenotypic strains. Therefore, we suggest that QoIs' action caused a high production of ROS, and that scavenging mechanisms such as mitophagy and peroxisomes functioned in RII strains to prevent oxidative stress, whereas RI strains were less capable of resisting oxidative stress, resulting in different resistance to QoIs. In this study, it was first revealed that mitophagy and peroxisome mechanisms available for ROS scavenging are involved in the resistance of pathogens to fungicides.
醌外抑制剂类杀菌剂（QoIs）是防治植物病害的关键杀菌剂，但随着QoIs的大量广泛使用，主要由G143A引起的抗性已被广泛报道。然而，在我们之前的研究中，具有相同G143A的两种表型（RI和RII）对QoIs表现出显著不同的抗性，这与报道的机制不相符。因此，本研究利用肟菌酯处理后RI和RII菌株的转录组分析来探索新的抗性机制。结果表明，332个差异表达基因（DEGs）显著上调，448个DEGs显著下调。GO和KEGG富集结果表明，DEGs在核糖体中富集最多，同时也在过氧化物、内吞作用、溶酶体、自噬和线粒体自噬中富集。特别是，线粒体自噬和过氧化物酶体在医学上已被报道为活性氧（ROS）清除的主要机制，而溶酶体和内吞作用分别是协助线粒体自噬的重要细胞器和生理过程。氧化应激实验表明，RII菌株的抗氧化应激能力显著高于RI菌株：具体而言，在0.12% H2O2浓度下，其抗氧化应激能力高出1.8倍以上。这表明两种表型菌株在ROS清除能力上确实存在显著差异。因此，我们认为QoIs的作用导致了ROS的大量产生，而线粒体自噬和过氧化物酶体等清除机制在RII菌株中发挥作用以防止氧化应激，而RI菌株抵抗氧化应激的能力较弱，从而导致对QoIs的抗性不同。在本研究中，首次揭示了可用于ROS清除的线粒体自噬和过氧化物酶体机制参与了病原体对杀菌剂的抗性。
