Investigation of the biological control potential of Endophytic penicillium and trichoderma species against fusarium root and crown rot in grapevine seedlings

Fusarium species, present naturally as endophytes in grapevine seedlings worldwide, including in Turkey, have become opportunistic pathogens under adverse environmental conditions in recent years and have begun to rank among the most significant fungal pathogens. These pathogens can cause severe yield losses by creating necrosis and root rot on the root and stem areas of seedlings. Currently, there is no economical and effective method to control these soil-borne pathogens. This study aims to investigate the biological control potential of endophytic species isolated from grapevine seedlings, namely Penicillium canascens, P. fructuariae-cellae, and Trichoderma brevicompactum, against pathogens such as F. annulatum, F. nirenbergiae, and F. curvatum, which cause crown rot and root rot in grapevines. For this purpose, culture filtrates, volatile metabolites, and dual culture tests were applied under in vitro conditions, while in vivo studies evaluated the biocontrol efficacy of endophytic species by applying their spore suspensions to the rhizosphere region of seedlings. In vitro experiments investigated the antagonistic interactions between endophytic and pathogenic species. In dual culture tests, T. brevicompactum was the most effective species against F. nirenbergiae with 47.6% inhibition, while P. canascens and P. fructuariae-cellae significantly limited the colony development of F. annulatum and F. curvatum species, with inhibition distances of 20 mm and 11 mm, respectively. In tests conducted with culture filtrates, T. brevicompactum and P. canascens inhibited the colony growth of all tested pathogens, while P. fructuariae-cellae was effective only against F. annulatum. In volatile metabolite analyses, it was determined that only T. brevicompactum inhibited colony development by 11% against the F. curvatum species; the other two endophytic species were not effective against the tested pathogens. Also, T. brevicompactum and P. fructuariae-cellae reduce the length of necrosis caused by pathogens in root regions by 34.8% to 65.2% and also increase root dry weight in vivo. However, when P. canascens and F. nirenbergiae were applied together, they were found to be ineffective in reducing the length of necrosis. Therefore, it was determined that they did not affect this species. The findings indicate that T. brevicompactum, P. fructuariae-cellae, and P. canascens can be used as potential biological control agents against Fusarium species that cause root and basal rot in grapevine seedlings.