Development of species‐specific primers for the ectoparasitic nematode species <i>Xiphinema brevicolle, X. diffusum, X. elongatum, X. ifacolum</i> and <i>X. longicaudatum</i> (Nematoda: Longidoridae) based on ribosomal DNA sequences

Abstract

Summary The objective of this study was to develop single‐step PCR species‐specific primers that reliably discriminate four economically important Xiphinema species ( X. brevicolle, X. elongatum, X. ifacolum and X. longicaudatum ) and X. diffusum that is taxonomically very similar to X. brevicolle. Each species‐specific reverse primer was located in the ITS‐1 rDNA region and was used in combination with a universal forward primer located in the 18S rDNA gene. Primer reliability was confirmed by screening seven and 11 populations, respectively of X. diffusum and X. elongatum. Potential species‐specific primers were also identified for X. brevicolle, X. longicaudatum and X. ifacolum , however too few populations of these species were available to thoroughly assess their reliability. For all species‐specific primers, specificity was demonstrated by the absence of cross‐reactions with 14 non‐target Xiphinema species. Multiplex PCR was effective and reproducible for two ( X. longicaudatum and X. ifacolum ) or three ( X. brevicolle, X. diffusum and X. elongatum ) of the target nematode species, thus improving the applicability of the diagnostic primers.