Trichoderma LR28 sp. as a potential biocontrol agent against peanut smut caused by Thecaphora frezii

VALETTI L ; POSADA GA.; BUSTAMANTE OM; SARDO MF; SUAREZ PA; ESPINOSA HERLEIN MA ; GONZÁLEZ NR; MONTEOLIVA MI,; PAREDES JA,; GUZZO MC

Rosario

Congreso; Congreso de la Sociedad de Fisiologia Vegetal 2023; 2023

SAFV

Thecaphora frezzii is the causal agent of peanut smut, which generates yield losses of up to 50%. Synthetic fungicides produce adverse effects on human health, food safety, and environmental quality. The use of biological commercial products in agriculture is increasing rapidly as an alternative to synthetic pesticides. Trichoderma spp. is the most widely used antagonistic fungus to control fungal diseases. In previous work, we selected the Trichoderma sp. LR28 strain for its antagonistic capacity against T. frezzii in vitro. Therefore, this study aimed to evaluate the antagonistic capacity of Trichoderma sp. LR28 against T. frezzii in vivo and the plant responses in terms of chlorophyll, oxidative stress, and antioxidative response. Peanut seeds were surface-sterilized and germinated at 25 °C for 7 days. Germinated seeds were sown in 8 L pots containing a mixed soil-vermiculite (4:1 v/v). Each pot was inoculated with T. frezzii spore (1x104 teliospores/g of soil). Trichoderma was sprayed with 4 ml of conidia suspension (1x108 conidia/ml) per plant. Suspension was applied at seeding, flowering, pegging, and their combinations. Biochemical responses to Trichoderma were measured as proline, FRAP, and chlorophyll contents. Smut intensity was assessed through incidence (as a percentage of diseased pods out of the total of sampled pods), disease severity index (DSI, using a five-class severity scale for peanut smut), and control efficiency (as a percentage of untreated plants). We observed variability in biochemical responses induced by Trichoderma inoculation. A significant decrease in severity index was observed in plants inoculated with LR28 in seed, flowering, and pegging compared to the untreated control. These results confirmed the biocontrol capacity of Trichoderma sp. LR28 strain and differential induction of biochemical changes remains to be further studied. Funding INTA 2019-I069, -I516, INTA 2023-I084, -I071, FONCyT PICT STARTUP 2018-0065