Morphologic, Morphometric, and Molecular Characterization of Vietnamese Populations of Meloidogyne incognita

Abstract

Meloidogyne incognita is considered the most damaging and common root-knot nematode causing serious damage to numerous host plants worldwide. During a survey of nematodes in Vietnam, 1106 samples from 22 different plant species were collected. Meloidogyne incognita was recorded on 13 of 22 host plants. Four populations of M. incognita from four host plants were chosen for comparison and confirmation of their morphological, morphometric, and molecular characteristics. Genetically-based phylogenetic trees were developed to show relationships among root-knot nematodes. Molecular barcodes of four gene regions, including ITS, D2-D3 of 28S rRNA, COI, and Nad5 mtDNA, integrated with morphological and morphometric data were used as reliable references for molecular identification of M. incognita. Our analyses indicated that tropical root-knot nematodes are very similar in characterization of ITS, D2-D3 of 28S rRNA and COI regions. However, these gene regions can be used to separate tropical root-knot nematode group from other groups. On the other hand, the analysis of Nad5 mtDNA and multiplex-PCR with specific primers can be used to distinguish tropical species.