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

Abstract

The transcription factor THCTF1 from Trichoderma harzianum, previously linked to the production of 6-pentyl-2H-pyran-2-one (6-PP) derivatives and antifungal activity against Fusarium oxysporum, 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 T. harzianum strains (wild type T34, transformant ΔD1-38 that is disrupted in the Thctf1 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). Thctf1 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 T. harzianum antifungal activity against Botrytis cinerea and in the beneficial effects leading to Arabidopsis plant development. The VOC blend from the disruptant ΔD1-38: (i) inhibited Arabidopsis seed germination for at least 26 days and (ii) when applied to Arabidopsis seedlings resulted in increased jasmonic acid- and salicylic acid-dependent defenses.

Biocontrol Potential of Trichoderma asperellum Strain 576 against Exserohilum turcicum in Zea mays

“…leads to notable improvements in root length, shoot length, and dry weight compared to control plants [ 24 , 37 , 81 ]. One of the mechanisms attributed to the plant growth promotion capabilities of plant growth-promoting microorganisms’ strains is the production of growth-promoting hormones such as indole-3-acetic acid (IAA), cytokinins, and gibberellins, which stimulate plant growth [ 82 ]. In our study, we demonstrated that the treatment of maize seedlings with T. asperellum 576 resulted in increased fresh and dry weight, as well as lateral root length.…”