Novel species and new records of Diaporthe causing eggplant leaf and fruit blight in the Philippines

Abstract

Fungal pathogens pose threats to crop productivity and food security. Management of fungal diseases can be achieved through an integrated disease management approach, including accurate identification of the causative agents. Diaporthe blight is a common disease of eggplant (Solanum melongena). Although Diaporthe vexans has been implicated as the causative agent, it was unclear until this study whether other Diaporthe species also contribute to this disease. In this study, leaf and fruit blights of eggplants were collected from different provinces in the Philippines. Through a polyphasic approach—morphological, cultural, pathogenicity, and multi-locus phylogenetic analyses of ITS, TEF1-α, TUB2, CAL, and HIS3 coupled with genealogical concordance phylogenetic species recognition analyses—we identified six Diaporthe speciesfrom the D. sojae species complex and D. arecae species complex. Two novel species, D. solani-melongenae and D. talong, along with the re-validated D. melongenae, and known species, viz., D. arecae, D. passifloricola, and D. vexans were identified as the causative agents of Diaporthe leaf and fruit blight of eggplant in the Philippines. Additionally, we also provide evidence supporting the synonymization of D. etinsidea with D. tulliensis, D. durionigena with D. rosae, and D. griceae with D. vexans. Our study confirmed that D. vexans is the major causative agent of eggplant blight in the country. All Diaporthe species were found to be pathogenic to eggplant. The results of this study contribute to the understanding of the eggplant blight disease, its potential spread, and the development of more targeted management strategies.