Comparison of the physiological effects of wild and mutated biological agents of Trichoderma spp. against Fusarium oxysporum f.sp. dianthi in carnation ‘White Liberty’

Carnation is an important ornamental plant and Fusarium oxysporum f.sp. dianthi is the causal agent of Fusarium wilt of carnation, causes a lot of damage to carnation growers. The aim of the present study was to investigate the response of carnation plants infected with F. oxysporum f.sp. dianthi and inoculated with Trichoderma (wild and mutant) on some physiological and enzymatic parameters related to resistance against pathogen. After isolating and identification of the pathogens and studying their pathogenicity, F. oxysporum N112 was selected as the virulent strain. Trichoderma isolates were prepared from the fungal collection of the Nuclear Agriculture Research Institute and their in vitro ability to inhibit growth against F. oxysporum N112 was studied. The reduction of disease incidence due to treatment with selected Trichoderma on carnation ‘ White Liberty’ in the greenhouse condition was investigated. The content of total protein, chlorophyll a and b, carotenoids as well as the activity of peroxidase and polyphenol oxidase enzymes in leaf samples were studied on days 7, 14 and 21. The results showed a decrease in the production of total protein, chlorophyll (a, b) and carotenoids in infected plants and an increase in the activity of peroxidase and polyphenol oxidase enzymes led to accumulation of free radicals in leaf tissue. While the plants inoculated with Trichoderma led to increase the content of total protein, chlorophyll (a, b) and carotenoids and prevented the accumulation of free radicals, it may related to reducing the accumulation of peroxidase and polyphenol oxidase enzymes in the carnation plant infected with Fusarum fusarum. f.sp. dianthi. On the other hand, treatment with mutant Trichoderma (NAS106-M21 and NAS114-M12) had more influence on the progression of the disease than wild isolates 21 days after disease infection, which was due to the effect of treatment with mutant Trichoderma in reducing cellular oxidation in the infected plant. The results showed that NAS106-M21 and NAS114-M12, in addition to higher antagonistic activity than the wild isolates (T. viride NAS106 and T. virens (NAS114)), through a greater effect on the cellular oxidation balance could be a more effective biocontrol agent in the integrated program to combat carnation Fusarium wilt.