RESUMEN
Ericoid mycorrhiza can improve the competitiveness of their host plants at the ecosystem level. The ability of ericoid mycorrhizal fungi to thrive under harsh environmental conditions suggests that they are capable of decomposing plant organic matter. This study aims to characterize 2 strains of root-cultivable endophytic fungi, RooDK1 and RooDK6, from Rhododendron ovatum Planch using colony and hyphal morphology, molecular analysis, observations of mycorrhiza, and investigations of adaptation to different sources of organic matter. Nitrogen utilization was also investigated by assessing protease production and growth on different nitrogen sources. Morphological studies indicated that both species are ericoid mycorrhizal fungi; our molecular studies confirmed RooDK1 as Oidiodendron maius and classified RooDK6 as Pezicula ericae. We observed that only RooDK1 can assist in host plant survival by degrading organic matter. This species also secretes protease and has the highest nitrate reductase activity of these 2 endophytes. Thus, RooDK1 has a greater ability to help the host plants thrive in a harsh habitat.