Interaction of Trichoderma Species with Fusarium graminearum Growth and Its Trichothecene Biosynthesis as Further Contribution in Selection of Potential Biocontrol Agents
Xianfeng Ren, Lixia Fan, Guidong Li, Ilya Lyagin, Bingchun Zhang, Mingxiao Ning, Mengmeng Yan, Jing Gao, Fei Wang, Changying Guo, Antonio Logrieco
Abstract
The interactions of Fusarium graminearum PG-Fg1 and its main trichothecenes with the 28 Trichoderma isolates were studied in vitro. The antagonistic effect assessed by dual-culture tests showed that Trichoderma isolates arrested the growth of PG-Fg1 after contact, overgrew the PG-Fg1 colony and inhibited the production of deoxynivalenol (DON), 3-acetyl-deoxynivalenol (3-ADON), and 15-acetyldeoxynivalenol (15-ADON) by up to 95.3%, 99.4%, and 99.6%, respectively. PG-Fg1 was hard to overgrow Trichoderma for further extension. Additionally, the inhibitory effects on PG-Fg1 by the Trichoderma metabolites, including volatiles and non-volatiles, were also investigated. Most of the Trichoderma isolates produced metabolites which inhibited PG-Fg1 growth and mycotoxins production. Specifically, Trichoderma non-volatiles and volatiles showed Fusarium growth inhibition rates ranging from 7% to 72% and 3% to 32%, respectively. Notably, non-volatile compounds from two isolates and volatiles from one isolate up-regulated the expression of DON biosynthesis genes (tri4 and tri5), leading to increased production of DON, 3-ADON, and 15-ADON. This study highlights the potential risk posed by certain Trichoderma strains as microbial agents, which can stimulate toxigenic fungi to produce higher levels of mycotoxins. Based on our results and previous reports, when selecting Trichoderma species as biocontrol agents against Fusarium graminearum, its effects on mycotoxins production should be carefully assessed, particularly given observed stimulatory impacts.