Biological control activities of Trichoderma asperellum AC.3 in inducing maize resistance against downy mildew disease

Abstract

This study aimed to evaluate the ability of Trichoderma asperellum AC.3 to induce resistance in maize plants against downy mildew caused by Peronosclerospora spp. The evaluation was done by analyzing increased defense-related biochemical activity, particularly peroxidase, polyphenol oxidase, tyrosine ammonia-lyase, and total phenolic content. Observation of the severity downy mildew was carried out inside a screen house with various treatments, including filtrate culture, conidial suspension, and sterile water. Each treatment was tested on 2 maize cultivars, namely JH 37 and Pulut Uri. The results showed that T. asperellum AC.3 induced resistance to downy mildew pathogen. The filtrate culture and suspension treatment had disease suppression between 15-39 % and 4–8% respectively. The correlation of these biochemical activities with maize defense response against downy mildew was shown by total phenolic content produced before infestation and at 48 hai, which greatly influenced the severity of the disease. In addition, the activity of the PPO enzyme at 24 hai affected the incubation period of downy mildew. The application of T. asperellum AC. 3 filtrate culture reduced the intensity of downy mildew in JH 37 and Pulut Uri varieties, as well as induced biochemical activities, specifically the accumulation of total phenolic content and PPO enzymes. Based on these results, T. asperellum AC.3 filtrate culture could be used against downy mildew of maize as a sustainable and environmentally friendly strategy.