Antagonistic activity and molecular characterization of biological control agent Trichoderma harzianum from Saudi Arabia

Abstract

Trichoderma harzianum is one of the most commonly used fungal species used in the biological control of plant pathogenic fungi. Its ability to control biological pathogens is strengthened by the production of analytic enzymes. In the identification of these fungal species, it has been noted that morphological characteristics alone are insufficient. Hence, the aim of this study was to identify 12 Trichoderma isolates based on their molecular markers and to evaluate the antagonistic activity of these Trichoderma isolates against several plant pathogens. The 12 Trichoderma/Hypocrea isolates were harvested from the rhizosphere of healthy tomato plants in Abha region, Saudi Arabia. These isolates were identified by both morphological and molecular techniques, such as the sequencing of the 5.8S-ITS region. Furthermore, based on the taxonomy and phylogeny of these isolates, the genetic similarities based on the intersimple sequence repeat-PCR markers separated the 12 Trichoderma isolates into 2 major clusters. The 12 isolates were then used in confrontational assays with Rhizoctonia solani, Pythium ultimum, and Alternaria solani. Most of the Trichoderma isolates showed a strong antagonistic activity, which could also be observed with the use of SEM. This study highlights the possibility of using T. harzianum in IPM programs as an effective biological agent against several pathogenic fungi.

Comparative molecular genetic diversity between Trichoderma spp. from Egypt and Saudi Arabia

“…BLAST search at NCBI was used to match the nucleotide sequences of all eight Trichoderma species for the post-molecular identification validation. This confirmed the selected sequences as specific strains of Trichoderma species (Srivastava et al 2014;Mazrou et al 2020). A set of 5 oligonucleotide sequences present in all known Hypocrea/Trichoderma ITS1 -5.8S RNA -ITS4 sequences, was used in combination to identify the species at a genetic level (Hassan 2014;Hassan et al 2019).…”

“…(Sharma et al 2009;Shahid et al 2013). Consequently, variation among individuals of the same species was noticed (Fahmi et al 2016;Hassan et al 2019;Mazrou et al 2020); therefore, it is of great interest to identify the species at the molecular level.…”

“…One of the main goals of the agricultural development is to secure enough food to the growing population worldwide, where the use of biotechnology is essential in this context (Mazrou et al 2020). The most significant agricultural-related problems in Egypt is the decrease in edible crops in the presence of an increasing population, the erosion of agricultural lands, and the loss of crops associated with diseases and pathogens (Hassan 2014 andMazrou et al 2020). One promising resolution to tackle these problems depends on the use of biological control.…”

Three New Reports of Trichoderma in Algeria: T. atrobrunneum, (South) T. longibrachiatum (South), and T. afroharzianum (Northwest)

“…We chose this molecular approach because the study of the morphological and cultural characteristics ( Table 1 ) could not efficiently distinguish Trichoderma strains up to the species level. Phenotypic traits are not constant and are influenced by culturing conditions [ 20 ], secondary metabolite production [ 6 ], and, particularly in Trichoderma , they can often be misleading because of the incorporation of many types of genes by horizontal gene transfer and mycoparasitism from plant-associated filamentous fungi belonging to different phylogenetically close classes of Ascomycota hosts [ 48 ].…”

“…In any case, it is necessary for a correct species characterization before registration and commercialization. Species identification based on traditional phenotypic methods is often time consuming and laborious, making this type of study difficult because of the unstable and subjective nature of the phenotypic characteristics, which are easily influenced by growing conditions [ 20 ]. Identification using molecular techniques combines a variety of parameters in order to properly identify species [ 21 ].…”