Additional information on Meloidogyne polycephannulata and its proposal as a junior synonym of M. incognita

Abstract

SummaryThe type population ofMeloidogyne polycephannulatais synonymised withM. incognitabased on morphological and morphometric characters, as well as biochemical, molecular and phylogenetic studies. Morphological variability and a wide host range were reported forM. incognitaduring its first description and later re-description.Meloidogyne polycephannulatawas described in Brazil from specimens collected in a carrot field (type population). The esterase phenotype (Est) characterised for this species was identical to the phenotype Est I2 ofM. incognita, the most ubiquitous phenotype used for diagnostics. Morphological and morphometric characters of the descriptions of the two nominal species showed major similarities, as well as variability within the range of variation detected inM. incognita. In PCR assays, three SCAR markers species-specific forM. incognita(incK14 F/R, Mi/FR and incB06 F/R) amplified the same fragments of 399 bp, 955 bp and 1200 bp, respectively, for populations in both species. In phylogenetic studies based either on concatenated sequences of ITS1-5.8S-ITS2, D2-D3 rRNA, mitochondrialCOII regions or on RAPD and AFLP data, the populations of both species grouped in the same clade with high bootstrap support. Altogether, these results provide congruent evidence that theM. polycephannulatatype isolate deposited at the Embrapa Cryopreserved National Collection of Root-knot Nematodes is not a valid species but rather a junior synonym ofM. incognita.