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Production of trichodiene by T richoderma harzianum alters the perception of this biocontrol strain by plants and antagonized fungi
Author(s) -
Malmierca Mónica G.,
McCormick Susan P.,
Cardoza Rosa E.,
Alexander Nancy J.,
Monte Enrique,
Gutiérrez Santiago
Publication year - 2015
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.12506
Subject(s) - trichothecene , trichoderma harzianum , biology , microbiology and biotechnology , botrytis cinerea , ergosterol , chitinase , trichoderma , gene , biochemistry , botany , biological pest control , toxin
Summary Trichothecenes are phytotoxic sesquiterpenic mycotoxins that can act as virulence factors in plant diseases. H arzianum A ( HA ) is a non‐phytotoxic trichothecene produced by T richoderma arundinaceum . The first step in HA biosynthesis is the conversion of farnesyl diphosphate to trichodiene ( TD ), a volatile organic compound ( VOC ), catalysed by a sesquiterpene synthase encoded by the tri5 gene. Expression of tri5 in the biocontrol strain T richoderma harzianum CECT 2413 resulted in production of TD in parallel with a reduction of ergosterol biosynthesis and an unexpected increase in the level of squalene. Transformants expressing tri5 displayed low chitinase activity and induced expression of B otrytis cinerea BOT genes, although their total antagonistic potential against phytopathogenic fungi was not reduced. VOCs released by the tri5 ‐transformant induced expression of tomato defence genes related to salicylic acid ( SA ), and TD itself strongly induced the expression of SA ‐responsive genes and reduced the development of lateral roots. Together, these results suggest that TD acts as a signalling VOC in the interactions of T richoderma with plants and other microorganisms by modulating the perception of this fungus to a given environment. Moreover, the TD ability to induce systemic defences indicates that complex trichothecene structures may not be necessary for inducing such responses.