Taxonomy and Phylogeny of Neopestalotiopsis and Pestalotiopsis Species Associated with Leaf Blight of Tea

Abstract

Fungal leaf blight of tea is increasingly associated with species belonging to the genera Neopestalotiopsis and Pestalotiopsis, which are known for their taxonomic complexity and wide host range. Accurate species delimitation and phylogenetic resolution are essential for understanding pathogen diversity and developing effective disease management strategies in tea plantations. The present study investigated the taxonomy and phylogeny of Neopestalotiopsis and Pestalotiopsis species associated with leaf blight of tea collected from major tea-growing regions. Symptomatic leaf samples exhibiting necrotic lesions, blight symptoms, and tissue degeneration were collected, and fungal isolates were obtained using standard isolation procedures. Morphological characterization was performed based on colony characteristics, conidial morphology, septation pattern, pigmentation, and appendage structure under microscopic examination. Significant morphological variability was observed among isolates, indicating the presence of multiple closely related species. Molecular identification was conducted using sequencing of ITS and multilocus gene regions, followed by phylogenetic analysis to resolve species boundaries and evolutionary relationships. The results revealed distinct clustering of isolates into several well-supported clades corresponding to different Neopestalotiopsis and Pestalotiopsis species complexes. Molecular data supported morphological observations and improved resolution of cryptic species that could not be reliably distinguished based on morphology alone. The study confirmed that tea leaf blight is associated with a diverse assemblage of Pestalotiopsis-like fungi exhibiting both genetic and morphological variation. The findings highlight the importance of integrated taxonomic approaches for accurate pathogen identification and provide insights into the epidemiology and evolution of leaf blight pathogens in tea ecosystems. This study supports the development of targeted disease management strategies for sustainable tea production.