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

Abstract

The rice sheath blight disease, caused by Rhizoctonia solani J.G. Kühn fungus, is a major disease of Oryza sativa 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, Trichoderma virens (J. H. Miller, Giddens and A. A. Foster) Arx was most effective in inhibiting the mycelial growth of R. solani in the dual culture (44.16% inhibition level), while Aspergillus fumigatus Fresen and T. virens had a 62.50–68.75% inhibition efficiency by volatile metabolites. In the slide culture, all of the isolates, except for T. harzianum Rifai, were effective in inhibiting the hyphae growth of R. solani. 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 T. virens. 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 Curnularia lunata (Wakker) Boedijn. The present in vivo and in vitro studies revealed that T. virens and A. fumigatus are the most effective antagonists in rice sheath blight disease control and could be applied in agricultural practice.

Mangrove endophytic fungi: Biocontrol potential against Rhizoctonia solani and biofertilizers for fragrant rice cultivation

“…Rhizoctonia solani , a soil-borne pathogen, poses significant economic threats to various crops, including rice, as it lacks a completely resistant cultivar [ 6 , 7 ]. Hence, there is an urgent need to explore non-chemical fungicidal measures to protect plants without harming soil biota.…”

“…The MRQ76 seeds were sterilized using a 5 % (v/v) Clorox solution and rinsed with SDW. After sterilization, the seeds were treated with a unique mixture of four antagonistic MEFs combined with R. solani , while the control group was treated with R. solani alone for 4 h using the spore suspension method, following Safari Motlagh et al [ 7 ] and the hyphal fragment suspensions for the R. solani isolate was prepared using the method described by Wang et al [ 43 ] with minor adjustments.…”

“…Sheath blight, triggered by the soil-borne, necrotrophic fungus Rhizoctonia solani ( R. solani ) J.G. Kühn, ranks as the second most devasting disease in rice, affecting yield significantly, especially in tropical Asia where it can reduce outputs from 10 to 50 % in major rice-producing areas [ 6 , 7 ]. Brunei, introduced Malaysian Rice Quality 76 (MRQ76) to increase the country's rice production.…”

“…Aspergillus terreus exhibits an antifungal mode of antagonistic effect to suppress R. solani in legumes, such as Phaseolus vulgaris and Vicia faba [ 15 ]. Safari Motlagh et al [ 7 ] demonstrated that Trichoderma virens and Aspergillus fumigatus act as mycoparasite antagonists, effectively controlling rice sheath blight disease.…”

Transcriptomic Response of Clonostachys rosea Mycoparasitizing Rhizoctonia solani

“…Biocontrol mycoparasites generally target living fungi that parasitize fungal pathogens as a type of biocontrol agent. Several mycoparasites containing Trichoderma strains ( T. asperellum , T. koningii , T. virens , T. harzianum , and T. atroviride ) and Clonostachys rosea have exhibited desirable control effects against plant diseases caused by R. solani [ 10 , 11 , 12 , 13 , 14 , 15 ]. In addition to screening more biocontrol mycoparasites, examining the mycoparasitism molecular mechanism is another an important pathway to further improving control efficacy against plant diseases caused by R. solani .…”