Defective RNA of a novel mycovirus with high transmissibility detrimental to biocontrol properties of Trichoderma spp.

Authors: YOU, JIAQI - Huazhong Agricultural University; LIU, XIAOLIN - Huazhong Agricultural University; WU, MINGDE - Huazhong Agricultural University; YANG, LONG - Huazhong Agricultural University; ZHANG, JING - Huazhong Agricultural University; Chen, Weidong; LI, GUOQING - Huazhong Agricultural University

Submitted to: Microorganisms
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/25/2019
Publication Date: 10/29/2019
Citation: You, J., Liu, X., Wu, M., Yang, L., Zhang, J., Chen, W., Li, G. 2019. Defective RNA of a novel mycovirus with high transmissibility detrimental to biocontrol properties of Trichoderma spp. Microorganisms. 7(11):507. https://doi.org/10.3390/microorganisms7110507.
DOI: https://doi.org/10.3390/microorganisms7110507

Interpretive Summary: The fungal species in the genus Trichoderma are widespread and often used as biocontrol agents of plant disease caused by other fungi. However, some biocontrol agents of Trichoderma species are unstable and often spontaneously change or actually decline in biocontrol efficacy. This research was conducted to dermine why Trichoderma harzianum isolate T-70 lost its ability to control disease. This strain has a virus named Trichoderma harzianum hypovirus 1 (ThHV1). A mutation causing defective RNA in the mycovirus caused reduced efficacy in biological control. This study provided an explanation to the frequently observed instability of some biocontrol agents in practical applications.

Technical Abstract: Trichoderma species are a group of fungi widely distributed in major terrestrial ecosystems, and are also commonly used as biocontrol agents for many plant diseases. A virus, namely Trichoderma harzianum hypovirus 1 (ThHV1) was identified in T. harzianum isolate T-70, and also infected isolate T-70D together with its defective RNA (ThHV1-S). Isolate T-70D carrying both ThHV1 and ThHV1-S showed abnormal biological properties, including decreased mycoparasitism ability when compared with isolate T-70. Both ThHV1 and ThHV1-S could be vertically transmitted to conidia and horizontally transmitted to T. harzianum isolate T-68 and T. koningiopsis T-51. The derivative strains carrying both ThHV1 and ThHV1-S showed decreased mycoparasitism ability, whereas strains carrying ThHV1 alone were normal, indicating that ThHV1-S is closely associated with the decreased mycoparasitism ability of T. harzianum isolate T-70D.