Phylogeny, distribution, and pathogenicity of fusarioid fungi associated with chickpea wilt in Sinaloa and Sonora, Mexico

Abstract Wilt disease complex, is the most important disease of chickpeas (Cicer arietinum L.) in the production areas from Mexico. Disease symptoms include root rot, yellowing, wilting, poor growth, discoloration of vascular tissues, and death of plants. This study aimed to identify the fusarioid species associated with chickpea wilt in northwest Mexico by the combination of phylogenetic analyses and morphological characterization, as well as to determine their pathogenicity and virulence on chickpea seedlings. A total of 80 isolates of fusarioid fungi were obtained from symptomatic plants of 16 chickpea fields distributed in Sinaloa and Sonora, Mexico. Subsequently, a subset of 41 isolates representing the range of geographic origin was selected for further morphological characterization, phylogeny, and pathogenicity tests. Phylogenetic analyses of partial fragments of the translation elongation factor 1-alpha (tef1-α) and RNA polymerase second largest subunit (rpb2) genes were used to determine the identity of 26 Fusarium isolates and 15 Neocosmospora isolates to species level. Pathogenicity tests were performed on chickpea seedlings (cv. Blanco Sinaloa) under greenhouse conditions. Phylogenetic analyses of 41 fungal isolates of this study allowed the identification of Fusarium languescens (51.2%), Neocosmospora falciformis (36.6%), F. nirenbergiae (7.3%), and F. verticillioides (4.9%). All fungal isolates were found to be pathogenic on chickpea seedlings and a significant difference in virulence was observed. To our knowledge, F. languescens and F. nirenbergiae, belonging to the Fusarium oxysporum species complex, as well as F. verticillioides belonging to the Fusarium fujikuroi species complex are recorded for the first time as causal agents of chickpea wilt in Mexico and worldwide.