Ceratocystis cacaofunesta is responsible of cocoa crops wilt in Colombia: morphological and molecular characterization of isolates

Abstract

Cocoa phytosanitary problems in Colombia are one of the main causes of the decline in cocoa production, with losses that can reach 100% due to inadequate management. Ceratocystis wilt is a prevalent disease affecting cocoa crops in the country, with C. fimbriata identified as its causal agent. However, there are still inconsistencies at the morphological level regarding the causal species, which contradict the causal relationship of the pathogen with the disease, affecting its diagnosis. Studies based on the phenotypic and genotypic characterization of Ceratocystis species are imperative for reliable identification of the pathogen. The objective of this study was to morphologically and molecularly characterize isolates of Ceratocystis spp. obtained from symptomatic samples in the cocoa-producing regions of Colombia. Morphological characteristics were evaluated at the macro and microscopic levels. Additionally, isolates were identified at the species level through multi-locus analysis and phylogenetic characterization using the β-tubulin (βT-1), guanine nucleotide-binding protein (MS204), second largest subunit of RNA polymerase II (RPBII), and 60 S ribosomal protein L37 (FG1093) gene regions. The results revealed variations in the colony development and microscopic morphology. Molecular and phylogenetic analyses consistently classified all isolates as Ceratocystis cacaofunesta, confirming that this species is the causal agent of cocoa Ceratocystis wilt in Colombia.