Huang Caiping, He Yuanyuan, Zhang Wei, Wang Jingpeng, Liu Mei, Deepali Borala Liyanage D, Yan Jiye
Beijing Key Laboratory of Environment Friendly Management on Fruit Diseases and Pests in North China, Institute of Plant Protection, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China.
Plant Cell Environ. 2025 Oct;48(10):7688-7698. doi: 10.1111/pce.70058. Epub 2025 Jul 13.
Lasiodiplodia theobromae (L. theobromae) is the causative agent of grapevine canker disease, which is a serious threat to global grape production. Currently, no effective fungicides are available to manage this disease. In this study, LtmilR2 was identified as an Argonaute1 (AGO1)-dependent small RNA produced by L. theobromae. Functional analysis revealed that both LtAGO1 and LtmilR2 negatively regulated the pathogenicity of L. theobromae. Through degradome sequencing, we identified LtRASGEF-a guanine nucleotide exchange factor involved in RAS signalling-as the target gene of LtmilR2. LtmilR2 suppressed the expression of LtRASGEF. Pathogenicity assays demonstrated that LtRASGEF was essential for fungal virulence. Furthermore, following infection, the expression of LtmilR2 rapidly decreased, while LtRASGEF expression quickly increased and positively regulated infection. Finally, we observed that the growth of L. theobromae was inhibited when an RNA duplex targeting LtmilR2 was delivered via the star polycation (SPc) nanocarrier, suggesting that LtmilR2 may serve as an RNA-based fungicide target for grapevine canker disease management.
可可毛色二孢菌（Lasiodiplodia theobromae，L. theobromae）是葡萄溃疡病的病原体，对全球葡萄生产构成严重威胁。目前，尚无有效的杀菌剂可用于防治这种病害。在本研究中，LtmilR2被鉴定为可可毛色二孢菌产生的一种依赖于AGO1（Argonaute1）的小RNA。功能分析表明，LtAGO1和LtmilR2均对可可毛色二孢菌的致病性起负调控作用。通过降解组测序，我们鉴定出LtRASGEF（一种参与RAS信号传导的鸟嘌呤核苷酸交换因子）是LtmilR2的靶基因。LtmilR2抑制LtRASGEF的表达。致病性测定表明，LtRASGEF对真菌毒力至关重要。此外，感染后，LtmilR2的表达迅速下降，而LtRASGEF的表达迅速增加并对感染起正调控作用。最后，我们观察到，当通过星型聚阳离子（SPc）纳米载体递送靶向LtmilR2的RNA双链体时，可可毛色二孢菌的生长受到抑制，这表明LtmilR2可能作为基于RNA的杀菌剂靶点用于葡萄溃疡病的防治。
