Trichoderma harzianum Volatile Organic Compounds Regulated by the THCTF1 Transcription Factor Are Involved in Antifungal Activity and Beneficial Plant Responses.

The transcription factor THCTF1 from , previously linked to the production of 6-pentyl-2-pyran-2-one (6-PP) derivatives and antifungal activity against , has been related in this study to conidiation, production of an array of volatile organic compounds (VOCs) and expression of methyltransferase genes. VOCs emitted by three strains (wild type T34, transformant ΔD1-38 that is disrupted in the gene encoding the transcription factor THCTF1, and ectopic integration transformant ΔJ3-16) were characterized by Proton Transfer Reaction-Quadrupole interface-Time-Of-Flight-Mass Spectrometry (PTR-Qi-TOF-MS). disruption affected the production of numerous VOCs such as the antifungal volatiles 2-pentyl furan and benzaldehyde which were under-emitted, and acetoine, a plant systemic defense inductor, which was over-emitted. Biological assays show that VOCs regulated by THCTF1 are involved in the antifungal activity against and in the beneficial effects leading to plant development. The VOC blend from the disruptant ΔD1-38: (i) inhibited seed germination for at least 26 days and (ii) when applied to seedlings resulted in increased jasmonic acid- and salicylic acid-dependent defenses.