Evaluation of Trichoderma harzianum ITEM 3636 as a potential endophyte and biocontrol agent against late leaf spot in peanut

GIORDANO DAMIAN FRANCISCO; ROUWS LUC; MOURA DE FREITAS KARINE; ERAZO JESSICA; PASTOR NICOLAS; DEL CANTO AGOSTINA; COELHO IRENE DA SILVA; ODDINO CLAUDIO; TORRES ADRIANA MABEL

PHYTOPATHOLOGY

AMER PHYTOPATHOLOGICAL SOC

Año: 2022 vol. 112 p. 6 - 6

0031-949X

Peanut late leaf spot, caused by Nothopassalora personata, is a disease that causes high yield losses in Argentina. Its management ismainly based on chemical fungicides, and there is frequently a low control efficiency with some of the active ingredients used.Trichoderma harzianum ITEM 3636 is efficient in the control of soil-borne pathogens. If this strain would have endophytic capacity andtrigger plant systemic resistance, it could decrease the disease intensity on leaves. To confirm this hypothesis, peanut seeds were treatedwith T. harzianum ITEM 3636 and sown under sterile conditions. After seven days, seedlings were processed, and their roots werestained for observation under a confocal microscope. Additionally, a greenhouse assay was carried out with inoculated and noinoculated seeds. Plants were inoculated at 130 days after sowing with an N. personata and disease intensity was recorded. Imagestaken under the microscope showed that T. harzianum ITEM 3636 was able to grow inside peanut roots, and the seed application undercontrolled conditions caused a significant decrease in late leaf spot intensity (more than 20% reduction in the number of infected leafletsand disease incidence). These results suggest that strain ITEM 3636 could constitute a useful tool for biological control of peanut lateleaf spot. Further studies are being carried out to elucidate the specific mechanisms involved in the capacity of the strain to induce plantresistance.