AUTHOR=Li Bo , Cao Yuhan , Ji Zixuan , Zhang Jingyi , Meng Xianglong , Dai Pengbo , Hu Tongle , Wang Shutong , Cao Keqiang , Wang Yanan 

TITLE=Coinfection of Two Mycoviruses Confers Hypovirulence and Reduces the Production of Mycotoxin Alternariol in Alternaria alternata f. sp. mali

JOURNAL=Frontiers in Microbiology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.910712

DOI=10.3389/fmicb.2022.910712

ISSN=1664-302X

ABSTRACT=Alternaria leaf blotch caused by Alternaria alternata Apple Pathotype (A. mali) is an important fungal disease that affects the production of apple worldwide. Mycoviruses harbored in plant pathogenic fungi can confer hypovirulence in their hosts and have attracted wide attention as potential biocontrol tools. In this study, two co-infection mycovieuses, named Alternaria altenata chrysovirus 1 strain QY2 (AaCV1-QY2) and Alternaria altenata magoulivirus 1 (AaMV1), respectively, were isolated from A. alternata f. sp. mali strain QY21. Sequence analyses revealed that AaCV1-QY2 virus belonged to the genus Betachrysovirus and AaMV1 virus belonged to the genus Magoulvirus. These two mycoviruses were found to be associated with hypovirulence in A. alternata, among which AaCV1-QY2 might play a relatively leading role. Because the elimination of AaMV1 from the strain QY21 do not affect hypovirulence trait, it indicated that the virus AaCV1-QY2 could independently induce slow growth and reduced virulence of the host. Moreover, the presence of viruses decreased the accumulation of mycotoxin alternariol (AOH) in A. alternata strains. Intriguingly, AaCV1-QY2/AaMV1 mycoviruses can be transmitted horizontally to other A. alternata strains, and co-infection can promote the interspecific transmission efficiency of AaCV1-QY2. To our knowledge, this study reports the first description of the member of Chrysovirus is related to hypovirulence in Alternaria spp., which facilitate the development of biocontrol measures of Alternaria mali Roberts.