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

Abstract

The objective of this study was to develop single-step PCR species-specifi c 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-specifi c 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 confi rmed by screening seven and 11 populations, respectively of X. diffusum and X. elongatum. Potential speciesspecifi c primers were also identifi ed for X. brevicolle, X. longicaudatum and X. ifacolum, however too few populations of these species were available to thoroughly assess their reliability. For all speciesspecifi c primers, specifi city 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.

Distribution and morphometrical characterization of Xiphinema pachtaicum, X. simile and X. brevicollum from Hungary

“…The morphometrics of the Hungarian isolate are in agreement with the original description of the species, but when compared with the topotypes (Luc et al, 1998), this Hungarian isolate has a longer body (2.1 vs 1.9 mm); and higher 'c' values (82 vs 77), shorter odontostyle (94 vs. 101 µm), a more anterior position of guiding ring (79 vs 86µm); and vulva (V=49.5 vs 53%). To resolve this contradiction, molecular methods (Lazarova et al, 2006;Oliveira et al, 2005) will have to be involved in future studies.…”

An update on the genus Longidorus, Paralongidorus and Xiphinema (Family Longidoridae) in Portugal

“…The application of molecular techniques to supplement taxonomic and systematics studies on the genus Xiphinema particularly in the X. americanum group has revealed that within the X. americanum-group some longassumed single species are in fact cryptic (i.e. genetically distinct but morphologically almost indistinguishable) (Barsi & De Luca 2008;Oliveira et al 2005Oliveira et al , 2006Archidona-Yuste et al 2016a;Lazarova et al 2016). Unfortunately, only a small number of Portuguese populations of this taxonomic group have been molecularly characterized (He et al 2005;Molinari et al 1997Molinari et al , 2006Lazarova et al 2006) and, as a result, the taxonomic status of some species of the X. americanum-group reported in Portugal has been contentious.…”

Morphometrics of Xiphinema dentatum Sturhan, 1978 from the Czech Republic

“…Morphometrics of J3 are similar to type population except ratio 'a' which is smaller (38.9, 37.1 vs 50) than the type population. It has been demonstrated that for routine identification of plant parasitic nematodes, DNA based diagnostics are quicker than the traditional strategy using morphology and morphometrics (Wang et al, 2003;Oliveira et al, 2005), but morphological identification is still a prerequisite for DNA based diagnostics. Therefore, in this research note detailed morphometrics of X. dentatum are provided from the Czech Republic.…”