0 avis
Bioactivity of Trichoderma harzianum A peptaibols against Zymoseptoria tritici causal agent of septoria leaf blotch of wheat
Archive ouverte
Edité par CCSD -
International audience. In this study Trichoderma harzianum strain A was isolated from the rhizosphere of an argan tree in southern Morocco. Trichoderma harzianum strain A had previously demon-strated a high antagonistic potential in vitro by direct confrontation and in vivo on wheat plants in pots under greenhouse conditions against Zymoseptoria tritici, the agent of sep-toria leaf blotch. In this study, the activity of filtrates prepared from the liquid culture of T. harzianum A alone and from the confrontation medium with two Z. tritici strains [G1-1 (durum wheat) and A5-1 (soft wheat)] on the inhibition of Z. tritici pycnidiospore germi-nation was studied by nephelometry. The results of the antibiosis assay revealed that filtrate 0 (A in confrontation with G1-1) and F3 (A against A5-1) showed 95% of G1-1 and A5-1 pycnidiospore inhibition at 9/10 dilution of the undiluted filtrates after 4 days of incuba-tion. To understand and explain the antifungal activity of these filtrates, the extraction and identification of secondary molecules of peptaibiotic nature secreted by T. harzianum A in the three studied filtrates were performed. According to the results of high-performance liquid chromatography-mass spectrometry (HPLC-MS) analyses, 38 peptaibiotic mo-lecules reported in the literature for their antifungal activity were identified in the differ-ent extracts at high concentrations (high peak intensities). These molecules are divided into nine groups, namely: Trichocryptin, Trichobrevin, Triochocryptin, Hypocompactin, Hyporodicin, Trichocompactin, Alamethicine, Trichoferin, and Trichokonin. It was also shown that the presence of the pathogen induces the production of peptaibols by the an-tagonistic strain of Trichoderma.
Consulter en ligne
Suggestions
Du même auteur
