Antagonistic effect of Trichoderma isolates and its metabolites against Fusarium solani and F. oxysporum in chickpea / Efeito antagonista de isolados de Trichoderma e seus metabólitos contra Fusarium solani e F. oxysporum em grão-de-bico

The aim of this work was to study and select Trichoderma sp. strains with biocontrol potential against Fusarium solani and F. oxysporum, the causal agents of root rot and wilt in chickpea. Antagonism against pathogenic isolates of F. solani and F. oxysporum of twenty-one isolates of Trichoderma sp. obtained from the rhizosphere of chickpea plants were evaluated in vitro through competition in dual culture tests as well as the production of volatile and non-volatile organic compounds exhibiting fungicidal and/or fungistatic activity. In the in vivo experiment, four isolates of Trichoderma sp. were selected and their antagonism was evaluated separately and combined with a commercial product based on T. asperellum under greenhouse conditions. Trichoderma sp. isolates were efficient competitors and produced metabolites capable of inhibiting mycelial growth of both species of Fusarium. Our results show the great versatility of the mechanisms of action from Trichoderma isolates, mainly associated with the production of volatile organic compounds. Despite the antagonistic effect of Trichoderma isolates observed in vitro, these isolates did not control Fusarium neither promote chickpea growth in in vivo conditions.

Antimicrobial potential of a biosurfactant gel for the prevention of mixed biofilms formed by fluconazole-resistant C. albicans and methicillin-resistant S. aureus in catheters

Dual-species biofilms formed by Candida albicans and Staphylococcus aureus have high virulence and drug resistance. In this context, biosurfactants produced by Pseudomonas aeruginosa have been widely studied, of which a new derivative (RLmix_Arg) stands out for possible application in formulations. The objective of this study was to evaluate the antibiofilm activity of RLmix_Arg, both alone and incorporated in a gel prepared with Pluronic F-127, against dual-species biofilms of fluconazole-resistant C. albicans (FRCA) and methicillin-resistant S. aureus (MRSA) in impregnated catheters. Broth microdilution tests, MTT reduction assays of mature biofilms, impregnation of RLmix_Arg and its gel in peripheral venous catheters, durability tests and scanning electron microscopy (SEM) were performed. RLmix_Arg showed antimicrobial activity against Candida spp. and S. aureus, by reducing the cell viability of mixed biofilms of FRCA and MRSA, and preventing their formation in a peripheral venous catheter. The incorporation of this biosurfactant in the Pluronic F-127 gel considerably enhanced its antibiofilm activity. Thus, RLmix_Arg has potential application in gels for impregnation in peripheral venous catheters, helping to prevent development of dual-species biofilms of FRCA and MRSA.We thank Central Analítica-UFC/CT-INFRA/MCTI-SISANO/Pro-Equipamentos, CNPq and CAPES for support: Grant PID2022-136354-NBI00 funded by MCIN/AEI/10.13039/501100011033 and by ‘ERDF A way of making Europe’; Grant PTA2020-018511-I funded by MCIN/AEI/10.13039/501100011033.Peer reviewe

Núcleos de Ensino da Unesp: artigos 2007

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq