Endophytic fungi of some medicinal plants in Egypt

Abstract

Article History Received:1/6/2016 Accepted: 15/7/2016: _________________ Keywords: Antagonism Biological control Endophytic Fungi Medicinal plants Thirty endophytic fungal species were isolated from eight healthy medicinal plants grown in their natural habitat in Egypt. These plants were basil, green onion, green pepper, mint, roselle, watercress, white radish and tagetes. Isolates were identified on the basis of morphological characteristics into 14 genera namely Acremonium, Alternaria, Aspergillus, Cladosporium, Cochliobolus, Epicoccum, Fusarium, Geosmithia, Macrophomina, Paecilomyces, Penicillium, Rhizopus, Scopulariopsis and Trichoderma. Also, a dark septate sterile mycelium isolate belonging to mycelia sterilia group was isolated. These endophytic fungi were evaluated for their biocontrol ability against Fusarium oxysporum the causal agent of wheat root rot disease. Alternaria alternata and Cochliobolus lunatus showed the highest antagonistic activity (71.43 % inhibition value) against the tested Fusarium oxysporum followed by Fusarium oxysporum and Cladosporium cladosporioides with percentages of 68.57 % and 60%, respectively. INTRODUCTION Medicinal plants are plants that provide people with medicines to prevent disease, maintain health or cure ailment''. The World Health Organization (WHO) defines a medicinal plant as any plant, which in one or more of its organs، contains substances that can be used for therapeutic purposes or which are precursors for chemo-pharmaceutical semi-synthesis (Balicket al., 1996). An ethno-biological survey revealed that about 8,000 species of medicinal plants are used as food supplements, medicines, biocides and other phytoch-emicals. The medicinal plants in Egypt represent a new promising resource as there is a relatively high representation of medicinal species in the native flora, that may induce the accumulation of a high concentration of secondary metabolites and there is a large market demand with higher economic value than other crops. All plant organs such as roots, rhizomes, flowers, leaves, fruits, seeds, as well as oils were used for medicaments in the form of powders, pills, suppositories, creams, pastes and ointments (Haggag, 1997). Endophytes refer to the microorganisms (mostly fungi and bacteria) colonizing the intercellular and intracellular regions of healthy plant tissues at a particular time, whose presence is unobtrusive and asymptomatic (Strobel, 2003and Schulz and Boyle, 2006). Endophytes form a symbiotic relationship with their plant host. It is believed that in many cases the microbes function as the biological defense for the plant against foreign phytopathogens.