Biocontrol of charcoal rot disease on tomato and melon using endophytic fungi in vitro and in vivo

Macrophomina phaseolina causal agent of charcoal rot, stem, and seedling rot, causes economic losses on over 500 plant species including tomato and melon around the world every year. One of the most important and effective alternative methods for chemicals and reducing their risks is biocontrol using different agents such as endophytic fungi. In the present study, the effect of some endophytic fungi on charcoal rot disease and the growth indices of tomato and melon plants were assessed. In the dual culture test, among the 12 endophyte species, five isolates including Chaetomium globosum 2S1, Ch. globosum 3L2, Fusarium fujikuroi 37F6, F. acuminatum GO2L1, and F. incarnatum 25S3 which had the highest inhibition of pathogen mycelia growth, were selected for further tests. In the volatile compounds test, all endophytic isolates showed more than 90% inhibition of pathogen mycelia growth. In biocontrol assay under greenhouse conditions, all endophytic isolates except F. fujikori 37F6, completely prevented disease on both tomato and melon plants. In the evaluation of the growth indices and by comparing the treated plants with the infected and healthy controls, no positive effect of the selected endophytic isolates was observed on the growth indices of both plants. However, they reduced the harmful effects of the pathogen and thus reduced the charcoal rot disease severity. Recovery of endophyte isolates from both inoculated melon and tomato plants showed that the surveyed isolates can become endophytes in plant tissue.