In vitro inhibition mechanism of Trichoderma asperellum isolates from corn against Rhizoctonia solani causing banded leaf and sheath blight disease and its role in improving the growth of corn seedlings

Abstract

Background One of the primary corn diseases, banded leaf and sheath blight, is carried on by the pathogenic fungus Rhizoctonia solani. Efforts to control R. solani are more directed at environmentally friendly control using a biological control agent, such as Trichoderma spp. as antagonistic agents and plant growth promoter. This study aimed to identify T. asperellum isolates based on molecular characteristics and to determine the in vitro inhibition mechanism against R. solani and its role in enhancing the growth of corn seedlings. Results The HMRP7, HMRF7A, HMEDF1B, HMEDF6A, and CHM01 isolates were identified as T. asperellum with a genetic distance coefficient value of 0.000 and a very high similarity of 100%. Meanwhile, the RsHM isolate was identified as R. solani with a homology level of > 90% and genetic distance coefficient values ranging from 0.000 to 0.032. The antagonistic ability showed that the five T. asperellum isolates were able to inhibit the growth of R. solani in vitro on PDA medium with an inhibition percentage of ≥ 50%, so they were categorized as antagonist agents. T. asperellum showed the antagonistic mechanism in inhibiting the R. solani growth through the action of parasitism. The five T. asperellum isolates tested on corn seedlings showed a significantly high difference from the control treatment on the observational variables of maximum growth potential (MGP), growth rate (GtR), growth simultaneity (GS), vigor index (VI), germination rate (GR), and median germination time (T50). Conclusion CHM01 isolate showed better potential than other isolates in inhibiting the growth of R. solani in vitro on PDA medium with a parasitism mechanism and enhancing the growth of corn seedlings.