Biocontrol of Fusarium oxysporum-infested Gastrodia elataBl. by Lactobacillus curvatus2768-VOCs and mechanism of inhibition

Gastrodia elata Bl. Is susceptible to infestation by the fungus Fusarium oxysporum, which can cause severe post-harvest diseases. This paper presents the findings of an investigation into the control and bacteriostatic mechanisms of Lactobacillus curvatus2768-VOCs on F. oxysporum-infected G. elata. The results of both in vitroand in vivotests demonstrated that L. curvatus2768-VOCs exhibited inhibitory effects against F. oxysporum, with inhibition rates of 63.37% and 44.4%, respectively. The results of the in vivotest also demonstrated that the pre-fumigation approach exhibited superior efficacy compared to direct fumigation, with the former showing a preventive effect. Furthermore, it was discovered that VOCs disrupted the integrity of F. oxysporumcell membranes and altered their permeability, resulting in the leakage of cell contents. The fumigation caused damage to the mycelial structure, accompanied by a notable decline in the total lipid and ergosterol content, and an appreciable increase in MDA content. Moreover, the fumigation of VOCs markedly diminished the activities of ATPase and mitochondrial dehydrogenase, thereby disrupting the respiration of F. oxysporumand its energy metabolism. The VOCs were subjected to GC-MS analysis, which revealed that the relative content of acids was the highest, particularly formic acid and glyoxalic acid. The study offers a theoretical basis for the biological control of postharvest diseases in G. elata.