Endophytic Fungi as Potential Biocontrol Agents against J.G. Kühn, the Causal Agent of Rice Sheath Blight Disease.

The rice sheath blight disease, caused by J.G. Kühn fungus, is a major disease of L. occurring all over the world. Therefore, efforts need to be undertaken to limit the spread of this pathogen, preferably by using environmentally friendly methods. In the present study, 57 fungal isolates were recovered by surface sterilization technique from 120 rice samples collected from paddy fields in Guilan province, Iran. Biological characterizations of the isolated taxa were performed in vitro, in the dual culture, volatile metabolites, and slide culture methods. Among the studied isolates, (J. H. Miller, Giddens and A. A. Foster) Arx was most effective in inhibiting the mycelial growth of in the dual culture (44.16% inhibition level), while Fresen and had a 62.50-68.75% inhibition efficiency by volatile metabolites. In the slide culture, all of the isolates, except for Rifai, were effective in inhibiting the hyphae growth of . Under greenhouse conditions, rice plants inoculated with these potential antagonistic fungi showed a reduction in disease severity by even 41.4% as in the case of . Moreover, phenotypic properties of rice, such as plant height, fresh weight, and dry weight were increased in the plants inoculated with all antagonistic fungi tested, compared to the infected plants, except for the fresh weight of plants inoculated with (Wakker) Boedijn. The present in vivo and in vitro studies revealed that and are the most effective antagonists in rice sheath blight disease control and could be applied in agricultural practice.