ISOLATION AND MOLECULAR CHARACTERIZATION OF EGYPTIAN TRICHODERMA AND ASSESSMENT OF THEIR ANTAGONISTIC POTENTIAL AGAINST RHIZOCTONIA SOLANI

Gamal Mohamedin Hassan,Nada Fathi Hemada,Zaki Ahmed El-Feky,Makram Ahmeed Sayed

doi:10.15414/jmbfs.2015.4.6.495-502

Gamal Mohamedin Hassan, Nada Fathi Hemada + Show 2 more

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https://doi.org/10.15414/jmbfs.2015.4.6.495-502

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Abstract

Morphological and molecular characterization of antagonistic ability of Trichoderma species was studied. Soil dilution plate method was used to isolate trichoderma from rhizosphere of bean, cowpea, cucumber, wheat and faba bean plants. Based on morphological and cultural characteristics, the Trichoderma isolates were identified as T. harzianum (10 isolates), T. koningii (8 isolates), and T. viride (2 isolates). A portion of rDNA, 560-600 bp was amplified from six biocontrol isolates using ITS1 and ITS 4 primers, and was sequenced and aligned against ex-type strain sequences from TrichoBlast and established Trichoderma taxonomy. Molecular phylogenetic analysis were performed based on nucleotide sequences in order to examine these isolates among 15 accession numbers of Trichoderma spp. found in GenBank. The results indicate that the FUE3, FUE5, FUE6, FUE9 and FUE18 Trichoderma isolates are closely related to Trichoderma koningii, while FUE15 isolate is closely related to Trichoderma harzianim .This result was in accordance with the result obtained from morphological and cultural characteristics. Production of volatile inhibitors and mycoparasitism were investigated using in vitro and in vivo tests in dual culture PDA medium and infected soils. The percent inhibitory effect against growth of Rhizoctonia solani was calculated, T. koningii FUE3 showed the greatest antagonistic effect to the pathogen (57.77%) in vitro experiment whereas T. koningii FUE6 and FUE18 were gave the highest reduction 96% of disease incidence caused by R. solani in greenhouse conditions.

Highlights

The species of Trichoderma are well known and provide an effective biological control against several plant pathogens that cause major problems in the agricultural crops
The results indicate that the FUE3, FUE5, FUE6, FUE9 and FUE18 Trichoderma isolates are closely related to Trichoderma koningii, while FUE15 isolate is closely related to Trichoderma harzianim .This result was in accordance with the result obtained from morphological and cultural characteristics
Phylogeny of Trichoderma and phylogenetic relationships of its species were investigated by maximum parsimony analysis and distance analysis of DNA sequences from multiple genetic loci. 18S ribosomal DNA (rDNA) sequence analysis suggests that the genus Trichoderma evolved at the same time as Hypomyces and Fusarium and about 110 Myr ago. 28S rDNA sequence analysis shows that the genus Trichoderma is part of a monophyletic branch within the Hypocreaceae (Gradinger et al, 2002).The molecular analysis of several strains revealed that the classification based on morphological data has been to a great extent, erroneous resulting in reclassification of several isolates and species, (Kuhls, et al.,1996).Druzhinina and Kubicek (2005) identified Trichoderma isolates according to the physiological, phenotypic characters and molecular markers

Summary

Introduction

The species of Trichoderma are well known and provide an effective biological control against several plant pathogens that cause major problems in the agricultural crops. Based on morphological and cultural characteristics, the Trichoderma isolates were identified as T. harzianum (10 isolates), T. koningii (8 isolates), and T. viride (2 isolates). Morphological characterization of Trichoderma species is based on microscopic measurements of mycelia fragments as well as growth rates of different isolates on different media at different temperatures, while molecular identification is based on sequence comparisons of ITS regions of rDNA gene.

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