Recognition of species belonging to Meloidogyne ethiopica group and development of a diagnostic method for its detection

Abstract

Root-knot nematodes (RKN) of the tropical group reproducing as a rule with mitotic parthenogenesis are highly polyphagous and damaging pests causing great losses in crop production. Morphometrical and molecular characters of three closely related tropical RKN species have been analysed in order to identify species-specific diagnostic parameters and examine the relationship between species. Morphometrical characters of M. ethiopica, M. luci and M. inornata isolates were similar and overlapped when compared between species and isolates of the same species indicating a very close relationship between the three species. Additionally, structure of map-1 genes was analysed, which provided the evidence of identical structure of map-1 family genes in M. ethiopica, M. inornata and M. luci. The unique structure of map-1 genes when compared to the other tropical RKN species further supports close relationship of the three species and therefore we have classified them together as M. ethiopica group. In addition, our results showed that the emergence of a virulent M. luci population does not correlate with the loss of map-1 genes as it was previously indicated for M. incognita (Castagnone-Sereno et al. 2009). Further, we have developed novel molecular methods to aid in identification of these nematodes: a PCR based method with primers specific for the M. ethiopica group comprising M. ethiopica M. luci and M. inornata, and a PCR based method with primers specific for the tropical RKN group species. Our results show that species of Meloidogyne ethiopica group share high similarity at morphological and genetic level.