The Effect of Trichoderma citrinoviride Treatment under Salinity Combined to Rhizoctonia solani Infection in Strawberry (Fragaria x ananassa Duch.)

Trihoderma citrinoviride protects plants from diseases by functioning as antagonists of many pathogenic fungi or by triggering the antioxidant defense system in plants. In the present study, to uncover the possible alleviative role of Trichoderma against salinity and Rhizoctonia solani infection, strawberry plants were pretreated Trichoderma citrinoviride and then subjected to salinity, R. solani and combined salinity and R. solani. The effect of T. citrinoviride on the alleviation of the effects of salt stress and Rhizoctonia solani infection was investigated by analysing leaf dry weight, PSII efficiency, and the activity of some antioxidant enzymes in the leaves of strawberry plants. T. citrinoviride improved competitive capability against salinity and R. solani infection. It showed 79% inhibition of the growth of pathogen R. solani. T. citrinoviride reduced 63% of the severity of disease in the leaves. Trichoderma pretreatment maximized plant dry weight. The T. citrinoviride-pretreated plants showed higher levels of PSII efficiency (Fv/Fm). Decreased lipid peroxidation and H2O2 accumulation compared to untreated seedlings under salt stress and R. solani infection was observed. Trichoderma-pretreated and –untreated plants respond differently to salt stress and R. solani infection by means of antioxidant defense. As compared to untreated seedlings, treated seedlings showed significantly lower activities of antioxidant enzymes, superoxide dismutase (SOD), peroxidase (POX), cell wall peroxidase (CWPOX) under salt stress and R. solani infection, indicating that treated seedlings might sense lower stress as compared to untreated seedlings. The study reports the effective adaptive strategy and potential of T. citrinoviride in alleviating the negative impact of salt stress and R. solani infection in strawberry.