Biocontrol Potential of Endophytic Fungi for the Eco-Friendly Management of Root Rot of Cuminum cyminum Caused by Fusarium solani

Abstract

Root rot disease of Cuminum cyminum caused by Fusarium solani is one of the most destructive diseases threatening cumin production. The present study investigates the biocontrol potential of some endophytes against F. solani and their effect on the induction of defense-related enzymes in a greenhouse. The results herein presented illustrate the strong biocontrol potential of three (out of twelve) endophytes. During the in vitro assay, three isolates demonstrated strong mycelial growth inhibition of F. solani: isolates 3, 4, and 9, with 87%, 65%, and 80% reductions, respectively, with respect to the control (100%). These isolates were identified as Trichoderma harzianum, T. longibrachiatum, and Chaetomium globosum, which produce siderophore and indole-3-acetic acid (IAA). Cumin seed priming with the culture filtrates of T. harzianum, C. globosum, and T. longibrachiatum positively affected the seed germination, as a higher germination (%) of culture filtrate-treated seeds was observed followed by infected and healthy control/untreated seeds. In the greenhouse, the application of T. harzianum, T. longibrachiatum, and C. globosum caused a reduction in disease severity (67.7%, 58.1%, and 59.3%, respectively) on cumin plants, with a lower disease severity (20%, 26%, and 25%, respectively) recorded in treated plants compared to the infected control (62%). Furthermore, a significant increase in defense-related enzymes in culture filtrate-treated cumin plants was recorded. Higher peroxidase (PO), polyphenoloxidase (PPO), and phenylalanine ammonia-lyase (PAL) activity, and a higher content of phenolic compounds, were found in culture filtrate-treated plants. These results indicate that the culture filtrates of these bioagents not only increased seed germination, but also protected the plants from F. solani infection by acting as important elements of the cellular antioxidant system in plants upon infection, conferring the biocontrol potential of C. globosum and Trichoderma species toward mitigating the root rot disease of cumin plants in a greenhouse.

Effects of a Mixture of Brevibacillus brevis with Other Bacillus sp. Strains against Gray Mold and on Enzyme Activities of Grape

“…One of the most important mechanisms of biological control agents is the induction of systemic resistance [46]. Different types of defense enzymes, such as PPO and CAT, have been found to play important roles in inducing disease resistance in plants [39]. GABAtreated Sporidiobolus pararoseus Y16 was found to effectively increase the activities of PPO, POD, PAL, and the content of total phenols and flavonoids in grapes [47].…”

“…The effect of microbial combination on the induction of defense-related enzyme production, such as polyphenol oxidase (PPO) and catalase (CAT), was determined in mixedmicrobial-combination-treated grape fruits (Vitis vinifera × Vitis labrusca, Kyoho grape) as described above in Section 2.6. The grape samples were collected at different times (0, 2, 4, and 5 days after treatment) and stored at −80 • C. The defense-related enzymes' activities were assayed using the method described by AboElyousr et al [39]. A reaction mixture lacking the sample was used as the bank.…”

Epidemiology and Control of Fungal Diseases in Crop Plants

“…Generally, biological control is regarded as an eco-friendly means to control plant diseases. Abo-Elyousr et al [11] investigated the biocontrol potential of endophytic fungi to control root rot, a destructive disease caused by Fusarium solan on cumin (Cuminum cyminum) that is a crop with important economic value in food and medicinal industries. From about 25 infected cumin root samples with root rot symptoms from Assiut Governorate, Egypt, seven fungal isolates were obtained and identified as Fusarium spp.…”