AUTHOR=Speckbacher Verena , Ruzsanyi Veronika , Martinez-Medina Ainhoa , Hinterdobler Wolfgang , Doppler Maria , Schreiner Ulrike , Böhmdorfer Stefan , Beccaccioli Marzia , Schuhmacher Rainer , Reverberi Massimo , Schmoll Monika , Zeilinger Susanne 

TITLE=The Lipoxygenase Lox1 Is Involved in Light‐ and Injury-Response, Conidiation, and Volatile Organic Compound Biosynthesis in the Mycoparasitic Fungus Trichoderma atroviride

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.02004

DOI=10.3389/fmicb.2020.02004

ISSN=1664-302X

ABSTRACT=<p>The necrotrophic mycoparasite <italic>Trichoderma atroviride</italic> is a biological pest control agent frequently applied in agriculture for the protection of plants against fungal phytopathogens. One of the main secondary metabolites produced by this fungus is 6-pentyl-α-pyrone (6-PP). 6-PP is an organic compound with antifungal and plant growth-promoting activities, whose biosynthesis was previously proposed to involve a lipoxygenase (Lox). In this study, we investigated the role of the single lipoxygenase-encoding gene <italic>lox1</italic> encoded in the <italic>T. atroviride</italic> genome by targeted gene deletion. We found that light inhibits 6-PP biosynthesis but <italic>lox1</italic> is dispensable for 6-PP production as well as for the ability of <italic>T. atroviride</italic> to parasitize and antagonize host fungi. However, we found Lox1 to be involved in <italic>T. atroviride</italic> conidiation in darkness, in injury-response, in the production of several metabolites, including oxylipins and volatile organic compounds, as well as in the induction of systemic resistance against the plant-pathogenic fungus <italic>Botrytis cinerea</italic> in <italic>Arabidopsis thaliana</italic> plants. Our findings give novel insights into the roles of a fungal Ile-group lipoxygenase and expand the understanding of a light-dependent role of these enzymes.</p>