Integrative taxonomy of Meloidogyne paranaensis populations belonging to different esterase phenotypes
Résumé
Meloidogyne paranaensis is one of the most destructive root-knot nematode species affecting coffee cultivation. This species presents different esterase phenotypes (Est): P1, P2 and P2a, previous studies showing that Est P2 and P2a populations were more aggressive to susceptible coffee cultivars than populations with Est P1, and local producers have even asked if they may be described as other species. The objective of this study was to characterise M. paranaensis populations of different esterase phenotypes (Est P1, P2 and P2a), regarding morphological, morphometric and phylogenetic relationships in distinct regions of ribosomal DNA (rDNA), mitochondrial gene cytochrome c oxidase II (COII) and nuclear protein coding gene HSP90. All populations were identified by esterase phenotype and SCAR-specific markers. Regarding morphology/morphometrics, the three populations were very similar to the description of the species, differing only in the morphology of the male stylet and second-stage juvenile hyaline tail length. Based on the phylogenetic analysis, a low intraspecific variability was detected among M. paranaensis Est P1 and Est P2 populations from Brazil; the Guatemalan population Est P2a, however, showed a genetic differentiation from the Brazilian populations, confirming the geographic genetic distance of this aggressive population. According to this multi-source approach study, in spite of the intraspecific variation, the phylogenetic position of M. paranaensis is absolute, regardless of the enzymatic phenotype and SCAR markers.