Mitochondrial haplotypebased identification of ethanolpreserved rootknot nematodes from Africa
Abstract
The asexual root-knot nematodes (RKNs) (Meloidogyne spp.) exemplified
by Meloidogyne incognita are widespread and damaging pests in
tropical and subtropical regions worldwide. Comparison of amplification
products of two adjacent polymorphic regions of the mitochondrial
genome using DNA extracts of characterized RKN strains, including 15
different species, indicate that several species are derived from the same
or closely related female lineages. Nevertheless, M. javanica, M. enterolobii,
M. incognita, and other key species could each be assigned unique
mitochondrial haplotypes based on polymerase chain reaction fragment
size and restriction cleavage patterns. M. arenaria isolates did not group
as a single haplotype, consistent with other reports of diversity within this
species. To test the utility of this assay, we characterized ethanol-preserved
samples from 103 single-species isolates from four countries in
sub-Saharan Africa (Benin, Nigeria, Kenya, and Tanzania). Mitochondrial
haplotypes corresponding to M. javanica and M. incognita were the most
prevalent. Samples from western Africa included several instances of
M. enterolobii but this species was not detected in samples from East
Africa. This protocol provides progress toward a standardized strategy for
identification of RKN species from small, preserved samples and a
rational starting point for classifying species present in regions where
previous knowledge has been limited.The asexual root-knot nematodes (RKNs) (Meloidogyne spp.) exemplified
by Meloidogyne incognita are widespread and damaging pests in
tropical and subtropical regions worldwide. Comparison of amplification
products of two adjacent polymorphic regions of the mitochondrial
genome using DNA extracts of characterized RKN strains, including 15
different species, indicate that several species are derived from the same
or closely related female lineages. Nevertheless, M. javanica, M. enterolobii,
M. incognita, and other key species could each be assigned unique
mitochondrial haplotypes based on polymerase chain reaction fragment
size and restriction cleavage patterns. M. arenaria isolates did not group
as a single haplotype, consistent with other reports of diversity within this
species. To test the utility of this assay, we characterized ethanol-preserved
samples from 103 single-species isolates from four countries in
sub-Saharan Africa (Benin, Nigeria, Kenya, and Tanzania). Mitochondrial
haplotypes corresponding to M. javanica and M. incognita were the most
prevalent. Samples from western Africa included several instances of
M. enterolobii but this species was not detected in samples from East
Africa. This protocol provides progress toward a standardized strategy for
identification of RKN species from small, preserved samples and a
rational starting point for classifying species present in regions where
previous knowledge has been limited.The asexual root-knot nematodes (RKNs) (Meloidogyne spp.) exemplified
by Meloidogyne incognita are widespread and damaging pests in
tropical and subtropical regions worldwide. Comparison of amplification
products of two adjacent polymorphic regions of the mitochondrial
genome using DNA extracts of characterized RKN strains, including 15
different species, indicate that several species are derived from the same
or closely related female lineages. Nevertheless, M. javanica, M. enterolobii,
M. incognita, and other key species could each be assigned unique
mitochondrial haplotypes based on polymerase chain reaction fragment
size and restriction cleavage patterns. M. arenaria isolates did not group
as a single haplotype, consistent with other reports of diversity within this
species. To test the utility of this assay, we characterized ethanol-preserved
samples from 103 single-species isolates from four countries in
sub-Saharan Africa (Benin, Nigeria, Kenya, and Tanzania). Mitochondrial
haplotypes corresponding to M. javanica and M. incognita were the most
prevalent. Samples from western Africa included several instances of
M. enterolobii but this species was not detected in samples from East
Africa. This protocol provides progress toward a standardized strategy for
identification of RKN species from small, preserved samples and a
rational starting point for classifying species present in regions where
previous knowledge has been limited.The asexual root-knot nematodes (RKNs) (Meloidogyne spp.) exemplified
by Meloidogyne incognita are widespread and damaging pests in
tropical and subtropical regions worldwide. Comparison of amplification
products of two adjacent polymorphic regions of the mitochondrial
genome using DNA extracts of characterized RKN strains, including 15
different species, indicate that several species are derived from the same
or closely related female lineages. Nevertheless, M. javanica, M. enterolobii,
M. incognita, and other key species could each be assigned unique
mitochondrial haplotypes based on polymerase chain reaction fragment
size and restriction cleavage patterns. M. arenaria isolates did not group
as a single haplotype, consistent with other reports of diversity within this
species. To test the utility of this assay, we characterized ethanol-preserved
samples from 103 single-species isolates from four countries in
sub-Saharan Africa (Benin, Nigeria, Kenya, and Tanzania). Mitochondrial
haplotypes corresponding to M. javanica and M. incognita were the most
prevalent. Samples from western Africa included several instances of
M. enterolobii but this species was not detected in samples from East
Africa. This protocol provides progress toward a standardized strategy for
identification of RKN species from small, preserved samples and a
rational starting point for classifying species present in regions where
previous knowledge has been limited.