Genetic polymorphisms of seven Trichoderma spp strains, their potential as biological control agent and growth promoter in tomato

Abstract

Abstract Currently, many conventional methods for crop management have been insufficient to cope with the effects of climate change on food production such as droughts, heat, soil nutrients deficiency and the occurrence of new pathogen strains. The utilization of biological inputs, such as Trichoderma spp, has proved useful to improve crop production and food safety. However, in Central American countries there is not enough expertise to accelerate, in a practical way, its use in a broader scale. Here, we report for first time the study of a collection of Trichoderma spp strains from Nicaragua and Honduras with the purpose of analyzing their genetic diversity their potential as biological control agent and growth promoter in tomato. Genetic diversity was estimated by sequencing the nuclear ribosomal internal transcribed spacer (ITS) region. After, bifactorial experiments for testing the potential of two strains (TN1C and TC01) and two structures (conidia and microsclerotia) for controlling a harmful strain of Fusarium solani were conducted, followed by bifactorial experiments, considering the same factors, but analyzing their effects as growth promoter in greenhouse conditions. The DNA sequences amplified from ITS regions (1‒F and 4) indicate that there are two species, T. asperellum and T. harzianum, instead of one, consistent with morphological observations. Bayesian and parsimony modeling clustered Trichoderma strains by species providing novel insights about phylogenetic relationships and nucleotide polymorphisms. The strains TN1C and TC01 showed a reduction in the percentage of damage caused by F. solani. In addition, these strains increase the percentage of seed germination, plant height, stem diameter and number of leaves in tomato seedlings and plants. Root length and volume increased only in seedlings. Microsclerotia had a better performance with respect to conidia on plant growth development. These results strengthen ongoing research projects and incipient biological control programs oriented to benefit tomato farmers.