Biometrical, biological, biochemical and molecular characteristics of isolates and related species

is one of the most polyphagous species of root-knot nematodes occurring in Brazil and worldwide. Eight isolates were studied, representing two enzymatic phenotypes (esterase and malate desydrogenase: I1/N1, I2/N1) and four cryptic sp.1 (S2/N1) isolates, representing one cytological type (3n = 40–46). Three isolates (Hi3/N1, 2n = 32–36) and two of an atypical sp.2 (S2a/N3, 3n = 40–44) were included in this study for comparison. All isolates were tested with three specific molecular markers The primer pairs B06F/R, miF/R and incK14F/R amplified three species-specific fragments of 1,200 bp, 955 bp and 399 bp, respectively for and sp.1 isolates. No amplification occurred in the and sp.2 isolates, except with primers miF/R (1,650 bp). The genetic variability of the spp. isolates was evaluated, using RAPD and ISSR markers. The phylogenetic analyses revealed two strongly supported monophyletic clades: clade I, consisting of and the atypical sp.2 isolates, and clade II, clustering together all and the sp.1 isolates. Considering the biometrical, cytological and molecular approaches, it was possible to conclude that the isolates with three enzymatic phenotypes (I1/N1, I2/N1 and S2/N1) presented the characteristics described for . Some correlations were detected between the isozymatic phenotypes and the tree topology (S2a/N3, Hi3/N1, I1/N1, S2/N1), but no strict correlation could be observed for the phenotype I2/N1 and one isolate of S2/N1. Morphologically, the Msp.2 isolates differ from and by the female stylet features presenting straight cone tip and round pear shaped knobs, posteriorly sloping. The results of this study suggested that the Msp.2 isolates with phenotypes S2aN3 belong to a new or an unidentified species closely related to .