Abstract

QUINTERO-MERCADO, Andrés; DANGON-BERNIER, Fabio  and  PAEZ-REDONDO, Alberto. Endophytic isolation of Colletotrichum spp. from the leaves and branches of mango (Mangifera indica l.) cultivar Azúcar in the municipality of Ciénaga, Magdalena, Colombia. Rev. acad. colomb. cienc. exact. fis. nat. [online]. 2019, vol.43, n.166, pp.65-77. ISSN 0370-3908.  https://doi.org/10.18257/raccefyn.788.

Anthracnose is the most limiting disease in mango crops in the department of Magdalena (Colombia), causing crop losses between 40 and 50%; worldwide, losses in the field of up to 51% of the crop have been reported and between 20 and 30% in postharvest. The causal agent, Colletotrichum spp., has a hemibiotrophic lifestyle, initially does not induce symptoms in its host, but later it changes to a necrotrophic stage. Endophytism is a lifestyle of Colletotrichum, but its role in pathogenicity is still uncertain, which led us to characterize endophytic isolates of Colletotrichum spp. from leaves and branches of mango, cultivar Azúcar, from a crop located in Ciénaga (Magdalena). The prevalence of the isolates in leaves and branches was determined considering three strata of the tree using three extraction protocols: (1) Chlorine chamber; (2) 4% sodium hypochlorite, and (3) 2% sodium hypochlorite. Morphometric descriptions included the colony, the conidia, and the appressoria. We tested pathogenicity in fruits and carried out the molecular identification of the most pathogenic isolates. We obtained nine endophytic isolates, eight in leaves and one in branches. The best extraction (18.2%) protocol was the one using 2% sodium hypochlorite. The highest prevalence was found in the upper strata of the tree (10% of the samples) and in the leaves (8.9% of the samples). The endophytic strains induced lesions diameter between 0,65-19,7 mm in diameter in fruits. The most virulent strain (HP3A-4) was identified as C. tropicale by molecular techniques. This is the first report in Colombia of this fungus acting as pathogenic endophyte on mango. The present study indicated that it is possible to find Colletotrichum as an endophyte in mango leaves and branches, which can cause infection when inoculated in fruits and evidences its high hidden inoculum potential for the development of anthracnosis. © 2019. Acad. Colomb. Cienc. Ex. Fis. Nat.

Keywords : Hemibiotrophic; Prevalence; Pathogenicity; Hidden inoculum; C. tropicale.

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