Antifungal Potentiality and Physiological Characterization of Trichoderma Isolates from Port Said Governorate

Abstract

A TOTAL of twenty Trichoderma isolates belonging to seven species were isolated from several locations at Port Said Governorate. Physiological characteristics of these isolates and their antagonistic effect against Sclerotinia sclerotiorum, the causative agent of white mold of Phaseolus vulgaris were evaluated. Trichoderma polysporum 2 showed the highest activity of total cellulase reached up to 2.95 filter paper unit ml-1. T. harzianum 2 had the highest endoglucanase activity (5.47 IU ml-1), whereas T. polysporum 1 had the highest chitinase activity (1.01 IU ml-1). Siderophores production was assayed using FeCl 3 , tetrazolium, Arnow's and spectrophotometric tests. Most of the isolates were able to produce hydroxamate and carboxylate types of siderophores. The ability of Trichoderma to produce indole acetic acid (IAA) and gibberellic acid (GA 3) were also investigated. Trichoderma harzianum 2 showed the highest concentration of IAA in broth medium reached up to 13.19µg/ml, whereas T. polysporum 1 showed the highest concentration of GA 3 by 586.51µg/ml. The antagonistic potentialities of Trichoderma isolates against Sclerotinia sclerotiorum were tested in vitro by using dual culture, base to base assay and the crude liquid extract effect of the isolates. Percentages of inhibition of radial growth of the pathogen by T. polysporum 1 in dual culture and crude extract methods were 45.97% and 87.78%, respectively. Also, the volatiles of T. piluliferum 2 showed a reduction of the radial growth by 66.85%. So, some Trichoderma isolates collected from Port Said soil showed high biocontrol activity against S. sclerotiorum.