Phytohormone Production Profiles in Trichoderma Species and Their Relationship to Wheat Plant Responses to Water Stress

Abstract

[EN] settingsOrder Article Reprints Open AccessArticle Phytohormone Production Profiles in Trichoderma Species and Their Relationship to Wheat Plant Responses to Water Stress by María IllescasORCID,Alberto Pedrero-MéndezORCID,Marcieli Pitorini-Bovolini,Rosa HermosaORCID andEnrique Monte *ORCID Institute for Agribiotechnology Research (CIALE), Department of Microbiology and Genetics, University of Salamanca, Campus de Villamayor, C/Duero, 12, 37185 Salamanca, Spain * Author to whom correspondence should be addressed. Pathogens 2021, 10(8), 991; https://doi.org/10.3390/pathogens10080991 Submission received: 6 July 2021 / Revised: 29 July 2021 / Accepted: 2 August 2021 / Published: 6 August 2021 (This article belongs to the Special Issue Beneficial Plant–Fungal Interactions) Downloadkeyboard_arrow_down Browse Figures Review Reports Versions Notes Abstract The production of eight phytohormones by Trichoderma species is described, as well as the 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase (ACCD) activity, which diverts the ethylene biosynthetic pathway in plants. The use of the Trichoderma strains T. virens T49, T. longibrachiatum T68, T. spirale T75 and T. harzianum T115 served to demonstrate the diverse production of the phytohormones gibberellins (GA) GA1 and GA4, abscisic acid (ABA), salicylic acid (SA), auxin (indole-3-acetic acid: IAA) and the cytokinins (CK) dihydrozeatin (DHZ), isopenteniladenine (iP) and trans-zeatin (tZ) in this genus. Such production is dependent on strain and/or culture medium. These four strains showed different degrees of wheat root colonization. Fresh and dry weights, conductance, H2O2 content and antioxidant activities such as superoxide dismutase, peroxidase and catalase were analyzed, under optimal irrigation and water stress conditions, on 30-days-old wheat plants treated with four-day-old Trichoderma cultures, obtained from potato dextrose broth (PDB) and PDB-tryptophan (Trp). The application of Trichoderma PDB cultures to wheat plants could be linked to the plants’ ability to adapt the antioxidant machinery and to tolerate water stress. Plants treated with PDB cultures of T49 and T115 had the significantly highest weights under water stress. Compared to controls, treatments with strains T68 and T75, with constrained GA1 and GA4 production, resulted in smaller plants regardless of fungal growth medium and irrigation regime.