Wu Xiaoqing, Lyu Yuping, Ren He, Zhou Fangyuan, Zhang Xinjian, Zhao Xiaoyan, Zhang Guangzhi, Yang Hetong
Shandong Provincial Key Laboratory of Applied Microbiology, Ecology Institute, Qilu University of Technology (Shandong Academy of Sciences), Ji'nan, China.
CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China.
J Appl Microbiol. 2022 Nov;133(5):2680-2693. doi: 10.1111/jam.15617. Epub 2022 May 24.
Oxalic acid (OA) is one of the pathogenic factors of Botrytis cinerea. Trichoderma afroharzianum exerts both antagonistic and oxalate-degrading effects on B. cinerea. This study aimed to investigate the relationship between the elimination of OA by T. afroharzianum and its antagonistic effects on B. cinerea.
Reversed-phase high performance liquid chromatogram (RP-HPLC) analysis showed that T. afroharzianum LTR-2 eliminated 10- or 20-mmol/L OA within 120 h, with the degradation being particularly efficient at the concentration of 20 mmol/L. RNA-seq analysis showed that the oxalate decarboxylase (OXDC) gene Toxdc, β-1,3-exoglucanase gene Tglu and aspartic protease gene Tpro of LTR-2 were significantly upregulated after treatment with 20-mmol/L OA. RT-qPCR analysis showed that under the conditions of confrontation, Toxdc and three cell wall degrading enzyme (CWDE) genes were upregulated before physical contact with B. cinerea. In addition, RT-qPCR analysis showed that OA synthesis in B. cinerea was not significantly affected by LTR-2.
The results revealed a correlation between OA degradation and mycoparasitism in T. afroharzianum when antagonising B. cinerea at the transcriptional level.
The relationship between OA degradation by T. afroharzianum and its effects against B. cinerea provide a new perspective on the antagonism of T. afroharzianum against B. cinerea. In addition, this study provides theoretical data for the scientific application of T. afroharzianum in the field of biocontrol.
草酸（OA）是灰葡萄孢的致病因子之一。哈茨木霉对灰葡萄孢具有拮抗和草酸降解作用。本研究旨在探讨哈茨木霉对OA的消除与其对灰葡萄孢拮抗作用之间的关系。
反相高效液相色谱（RP-HPLC）分析表明，哈茨木霉LTR-2在120小时内消除了10或20 mmol/L的OA，在20 mmol/L浓度下降解尤为高效。RNA测序分析表明，用20 mmol/L OA处理后，LTR-2的草酸脱羧酶（OXDC）基因Toxdc、β-1,3-外切葡聚糖酶基因Tglu和天冬氨酸蛋白酶基因Tpro显著上调。实时定量PCR（RT-qPCR）分析表明，在对峙条件下，Toxdc和三个细胞壁降解酶（CWDE）基因在与灰葡萄孢物理接触前上调。此外，RT-qPCR分析表明，LTR-2对灰葡萄孢中OA的合成没有显著影响。
结果揭示了哈茨木霉在转录水平上拮抗灰葡萄孢时，OA降解与真菌寄生之间的相关性。
哈茨木霉对OA的降解与其对灰葡萄孢的作用之间的关系为哈茨木霉对灰葡萄孢的拮抗作用提供了新的视角。此外，本研究为哈茨木霉在生物防治领域的科学应用提供了理论数据。
