AUTHOR=Li Ningxiao , Alfiky Alsayed , Wang Wenzhao , Islam Md , Nourollahi Khoshnood , Liu Xingzhong , Kang Seogchan 

TITLE=Volatile Compound-Mediated Recognition and Inhibition Between Trichoderma Biocontrol Agents and Fusarium oxysporum

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.02614

DOI=10.3389/fmicb.2018.02614

ISSN=1664-302X

ABSTRACT=<p>Certain <italic>Trichoderma</italic> strains protect plants from diverse pathogens using multiple mechanisms. We report a novel mechanism that may potentially play an important role in <italic>Trichoderma</italic>-based biocontrol. <italic>Trichoderma virens</italic> and <italic>T. viride</italic> significantly increased the amount/activity of secreted antifungal metabolites in response to volatile compounds (VCs) produced by 13 strains of <italic>Fusarium oxysporum</italic>, a soilborne fungus that infects diverse plants. This response suggests that both <italic>Trichoderma</italic> spp. recognize the presence of <italic>F. oxysporum</italic> by sensing pathogen VCs and prepare for attacking pathogens. However, <italic>T. asperellum</italic> did not respond to any, while <italic>T. harzianum</italic> responded to VCs from only a few strains. Gene expression analysis via qPCR showed up-regulation of several biocontrol-associated genes in <italic>T. virens</italic> in response to <italic>F. oxysporum</italic> VCs. Analysis of VCs from seven <italic>F. oxysporum</italic> strains tentatively identified a total of 28 compounds, including six that were produced by all of them. All four <italic>Trichoderma</italic> species produced VCs that inhibited <italic>F. oxysporum</italic> growth. Analysis of VCs produced by <italic>T. virens</italic> and <italic>T. harzianum</italic> revealed the production of compounds that had been reported to display antifungal activity. <italic>F. oxysporum</italic> also recognizes <italic>Trichoderma</italic> spp. by sensing their VCs and releases VCs that inhibit <italic>Trichoderma</italic>, suggesting that both types of VC-mediated interaction are common among fungi.</p>