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Phylogenetic relationships among populations of the N acobbus aberrans ( N ematoda, P ratylenchidae) complex reveal the existence of cryptic species
Author(s) -
Lax Paola,
Rondan Dueñas Juan C.,
Gardenal Cristi.,
Doucet Marcelo E.
Publication year - 2014
Publication title -
zoologica scripta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.204
H-Index - 64
eISSN - 1463-6409
pISSN - 0300-3256
DOI - 10.1111/zsc.12043
Subject(s) - biology , phylogenetic tree , clade , sensu , genetic divergence , population , species complex , nematode , taxonomy (biology) , phylogenetics , zoology , evolutionary biology , botany , genetic diversity , ecology , gene , genetics , genus , demography , sociology
The plant‐parasitic nematode N acobbus aberrans sensu lato is an agricultural pest of quarantine importance. Due to the morphometric, physiological and genetic variability observed within the species, there is no agreement on the taxonomy of this nematode. The objective of this study was to analyse the ITS r DNA region and the D 2– D 3 expansion segments of 28 S r DNA in 10 A rgentine populations and one from E cuador and to establish their phylogenetic relationship with other known sequences from S outh and N orth A merica. Phylogenetic trees of the ITS gene showed seven statistically well‐supported clades; the high and significant F st values obtained among these groups confirmed this partitioning. The A rgentine populations here considered were separated into three clades: one comprising a population from the A ndean region and two grouping nematodes from lower altitudes. Three other clades were distinguished for S outh A merican populations, which included known sequences of individuals from P eru, B olivia and north of A rgentina. The other clade included sequences from M exico, E cuador and two A rgentine populations of unknown origin. The important degree of genetic divergence observed among A ndean populations suggests that the A ndes may have played a crucial role in speciation of N acobbus , which would have originated in this region. Although D 2– D 3 segments exhibited lower variation, they were useful for establishing phylogenetic relationships among the A rgentine populations considered in this work. As there are no other G en B ank sequences available for these segments, it was not possible to make comparisons with other populations from S outh and N orth A merica. The considerable genetic differentiation observed in ITS r DNA region among N acobbus populations showed evidence of cryptic species within the N . aberrans s.l . complex. Integration of morphological and morphometric studies and molecular analyses considering other genes may aid in the identification of species and their phylogenetic relationships within this genus.