Biological control of southern corn leaf blight by Trichoderma atroviride SG3403

Trichoderma atroviride SG3403 showed high biocontrol activity against southern corn leaf blight (SCLB; pathogen: Cochliobolus heterostrophus). T. atroviride SG3403 could cause death of C. heterostrophus race O hypha on plates. Spraying T. atroviride SG3403 conidia suspension over maize seedling leaves protected the corn from SCLB infection. Biocontrol effect lasted for 30 days in the field. Trichoderma strain was able to induce resistance response in corn leaves against pathogen infection. In corn leaves treated with T. atroviride SG3403, the enzyme activities of phenylalanine ammonia lyase (PAL) and superoxide dismutase (SOD) reached the highest at 24 h, enzyme activity of catalase (CAT) reached the highest at 36 h after inoculation of pathogen C. heterostrophus race O. RNA expression levels of Pal, Sod and Cat (which synthesis enzyme PAL, SOD and CAT) were also upregulated and corresponded to the enzyme activity at the same time point. Enzyme activities and corresponding genes expression induced by Trichoderma SG3403 was more obvious than that induced by pathogen only, which implies that T. atroviride SG3403 induced corn defense gene expression against pathogen infection. Thus, induced resistance mechanism was possibly involved in the biocontrol of SCLB by T. atroviride SG3403.