Biocontrol potential of salinity tolerant mutants of Trichoderma harzianum against Fusarium oxysporum

Abstract

Exposing a wild-type culture of Trichoderma harzianum to gamma irradiation induced two stable salt-tolerant mutants (Th50M6 and Th50M11). Under saline conditions, both mutants greatly surpassed their wild type strain in growth rate, sporulation and biological proficiency against Fusarium oxysporum, the causal agent of tomato wilt disease. Tolerant T. harzianum mutants detained a capability to grow and convinced sporulation in growth media containing up to 69 mM NaCl. In comparison with their parent strain, characterization of both mutants confirmed that they have reinforced contents of proline and hydroxyproline, relatively higher sodium content compared to potassium, calcium or magnesium contents, higher level of total phenols. Electrophoretic analysis of total soluble proteins in the salt tolerance mutant Th50M6 showed different bands accumulated in response to 69 mM NaCl. Data also showed that mutants produce certain active metabolites, such as chitinases, cellulases, β-galactosidases, as well as, some antibiotics i.e., trichodermin, gliotoxin and gliovirin. Trichoderma mutants significantly reduced wilt disease incidence and improved yield and mineral contents of tomato plants under both saline and non-saline soil conditions, as well as, under infested and natural conditions. T. harzianum mutants were also more efficient in dropping the F. oxysporum growth in rhizosphere compared to the wild type strain. Population density of both mutants in rhizosphere far exceeded that of T. harzianum wild type strain.

Exploitation of trichoderma species on the growth of Pythium Aphanidermatum in Chilli

“…The antagonists isolated from chilli rhizosphere performed better in inhibiting the growth of P. aphanidermatum. This is in consistent with earlier findings (22). Similarly, T. viride inhibited the growth of P. aphanidermatum in tomato (16); in turmeric (33) and many hosts (21).…”

Biological control of Rhizoctonia solani in tomatoes with Trichoderma harzianum mutants

“…These results suggest that mutants obtained either by chemical or UV treatments, with the exception of Th11C40.1, have improved their biocontrol activity in relation to their parental strains. The obtainment of Trichoderma mutants through different procedures has allowed the obtainment of hyperhydrolytic strains with improved biocontrol activity on R. solani (Rey et al 2001), of protease overproducing strains with improved biocontrol activity against different pathogens (Szekeres et al 2004), of salt tolerant strains for the control of F. oxysporum (Mohamed and Haggag, 2006) and of pesticide polyresistant strains (Hatvani et al 2006), thus supporting the improved biocontrol effect of some of the mutants tested in this work.…”

Gamma irradiation in modulating cadmium bioremediation potential of Aspergillus sp.

“…Mutation of fungi for making them metal resistant are usually done by chemical applications [23][24]. Some groups have worked on use of UV radiation to induce metal resistance in bacteria [25][26].It is already reported that exposure to gamma showed maximum potential to induce mutation in fungi (Metarhizium anisopliae) than that of UV or other chemical mutagens [14].Gamma exposed fungal strain improvement for different industrial as well as ecological purposes are also reported earliar [27][28]. Thus our study showed that possibility of utilising gamma irradiation for increasing Cd removal efficiency of fungi.…”