Identificación morfológica y molecular de hongos fitopatógenos en cultivos de banano (musa x paradisiaca) en la isla santa cruz-galápagos

Abstract

This study aimed to identify morphologically and molecularly the phytopathogenic fungi in banana crops on the island of Santa Cruz-Galápagos. Through purposeful sampling, 217 samples were collected and discriminated until reduced to 16 samples; then, the phytopathogenic fungi were isolated after disinfection treatment, in a PDA (Potato Dextrose Agar) culture medium, at an incubation temperature of 25 ° C; in which from the fifth day the growth of the different species was observed. Morphological characteristics such as colour, edge shape, texture, elevation, and presence of rings were described, in which colonies similar to the species of the genus Collectotrichum sp., which is responsible for anthracnose, stood out. In the same way, isolates of phytopathogenic fungi were molecularly identified by DNA isolation with Plant Pure Link extraction kit (Invitrogen), amplification with Master Mix DreamTaq Green (Thermo Scientific™) and primers (ITS1-ITS4), it was purified. PCR products were obtained, sequencing was performed, the sequences were edited, and their identity was determined; consequently, eight samples were obtained that obtained similarity of the ITS regions of each isolate in the NCI BLAST. Finally, the sequences obtained from the isolate were compared with accessions of the genus Colletotrichum, available in GenBank and presented 100% similarity in their phylogenetic analysis. It is concluded that many banana plants in the farms of Santa Cruz Island have the anthracnose disease, Collectotrichum siamese being a species commonly a pathogen in a wide range of hosts; therefore, the presence of this species was verified. Studying other islands in the Galapagos is recommended to measure the spread of different diseases and thus generate an action plan to deal with this problem.