Paramyrothecium travancorense: A novel fungal pathogen causing leaf spots and blights on Coffea travancorensis in Kerala, India

Abstract

The Western Ghats, a renowned biodiversity hotspot, holds immense biological and geographical significance. Kerala, located in this region, harbors diverse forests featuring major Indian forest types. Its favorable climatic conditions support the thriving growth of a wide variety of microbiota. During roving survey, Coffea travancorensis (Rubiaceae), a wild coffee plant exhibiting symptoms of leaf spot and blight disease was collected from medicinal plants garden of Kerala Forest Research Institute, near the Peechi-Vazhani Wildlife Sanctuary, Kerala. The fungal pathogen associated with the disease was isolated using the standard tissue isolation method and its pathogenicity was confirmed. Identification of the fungal pathogen was performed based on morpho-cultural characteristics and multigene sequence analysis (ITS, LSU, and tub2 regions). The analysis revealed that the leaf-pathogenic fungus belongs to Paramyrothecium travancorense. Phylogenetic analysis further showed that P. travancorense formed a distinct clade, separated from the closely related species, P. roridum and P. breviseta. However, morphologically, P. travancorense differs from these species as its conidiophores and conidia are larger. Additionally, setae are absent in P. travancorense, whereas they are present in P. roridum and P. breviseta. This study represents the first record of the novel fungal pathogen P. travancorense on C. travancorensis. The findings highlight the need for enhanced disease monitoring and the development of sustainable, effective management strategies to mitigate its impact, thereby supporting conservation efforts and crop resilience in Kerala, India.