Integrated characterization and in vitro biocontrol of Fusarium sp. using Trichoderma asperellum

Abstract

Pepper is a crop of great economic importance in Mexico. However, it is affected by multiple diseases. The aim of this research was to identify through morphological and molecular methods the causal agent of both foliar and root wilting in jalapeño pepper plants (Capsicum annuum L.), and the ability of Trichoderma asperellum to control these diseases in vitro. The causal agent of the disease was isolated from soil and foliar samples of jalapeño pepper fields in Delicias, Chihuahua, Mexico. The fungus was cultured on solid PDA medium to study its morphology. The CTAB method was used to extract DNA from Fusarium sp. The ITS1 and ITS4 primer pair was used to amplify a 850 bp DNA fragment by PCR. The sequence was deposited in Genbank (acc. no. OR801070) and used for phylogenetic analysis using Bayesian inference. The analysis revealed five clades and the isolate was placed in clade 4, which showed high genetic similarity with F. oxysporum (99.28% identity). Based on these molecular, morphological and phylogenetic data, the isolate was identified as Fusarium oxysporum Schltdl. The biocontrol potential of T. asperellum (accession No. MN95047) against F. oxysporum was tested in vitro and it showed 40% to 87.5% inhibition of the pathogen. These findings are important for managing this pathogen and reducing the use of chemical fungicides.

Keywords

• antagonistic
• biocontrol
• Capsicum annuum L.
• fungal disease
• Trichoderma