Biocontrol and growth promoting effect of Trichoderma spp. isolate from rhizosphere soils of some Algerian areas

Abstract

Trichoderma species are ubiquitous fungi in the environment exhibiting enormous potential in biotechnology especially due to their plant health benefits, such as conferring stimulation growth and disease resistance to their hosts.The aim of this study was to identify isolated Trichoderma strains by molecular tools and evaluate their in vitro antagonistic activity against four common phytopathogenic fungi as well as their biostimulant activity. Tewenty two Trichoderma strains were isolated from different rhizosphere soils and eleven species were identified at the species level among these strains, however, two Trichoderma strains could not be identified. These results were obtained using tef1 marker known as highly efficient barcode marker for Trichoderma species identification. At the moment, the following species are reported for the first time in Algeria: T. tomentosum, T. hamatum, T. aureoviride, T. citrinoviride, T. samuelsii et T. hispanicum. All isolated Trichoderma strains were tested in dual cultures against four plant pathogens: Ascochyta rabiei, Botrytis cinerea, Drechslera graminea and Fusarium graminearum. Most of Trichoderma strains showed effective antagonistic activity either by overgrowing up to pathogen colonies or coiling around them. T. gamsii showed the highest Percentage of Radial Inhibition Growth (PRIG%) with rates varying between 51,9 % to 65,5 %. Then, tomato root seedlings were inoculated with spore suspension of Trichoderma isolates and thirty days after growth culture, some plant growth parameters were measured. We observed that Trichoderma strains which exhibited high biostimulant potential, had not raised biocontrol performance proving that the Trichoderma strains do not necessarily raised the dual performances.