MORPHOMETRIC AND MOLECULAR IDENTIFICATION OF ROOT-LESION NEMATODES, PRATYLENCHUS SPP., FROM COSTA RICA
Abstract
Root-lesion nematodes, Pratylenchus spp., are among the top three most significant nematode parasites of a wide range of vascular plants including several economically important crops. There are more than 100 described species. Identification at the species level is difficult due to morphological similarities and overlapping morphometric characters. This research was carried out between 2017 and 2019 with the aim of identifying Pratylenchus species associated with four crops in Costa Rica. Species of Pratylenchus were identified by their morphological features and with molecular methods. For molecular analysis, rDNA 28S expansion segments D2-D3 were amplified by PCR with D2A and D3B primers and the ITS1 region with the 18S and rDNA1 primers, which were subsequently sent for sequencing. Phylogenetic relationships between Pratylenchus species were established by Bayesian Inference, based on the sequences analyzed. Three species of Pratylenchus were detected: P. brachyurus associated with pineapple (Ananas comosus), P. coffeae with plantain (Musa paradisiaca), and P. zeae associated with rice (Oryza sativa) and star grass (Cynodon nlemfuensis). Of the three Pratylenchus species identified in this research, this is the first report of P. zeae associated with star grass in Costa Rica, however, this species had already been reported in rice in the country.