Open AccessA species‐specific satellite DNA family in the genome of the coffee root‐knot nematode Meloidogyne exigua : application to molecular diagnostics of the parasite
Author(s) -
Randig Onivaldo,
Bongiovanni Michel,
Carneiro Regina M. D. G.,
Sarah JeanLouis,
CastagSereno Philippe
Publication year - 2002
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1046/j.1364-3703.2002.00134.x
Subject(s) - biology , exigua , satellite dna , genome , genetics , nematode , dna sequencing , dna , globodera pallida , genomic dna , root knot nematode , repeated sequence , gene , spodoptera , recombinant dna , solanaceae , ecology
SUMMARY A new Bgl II satellite DNA has been isolated, cloned and sequenced from the coffee root‐knot nematode, Meloidogyne exigua (Nematoda: Tylenchida). It is represented as tandemly repeated sequences with a monomeric unit of 277 bp. The monomers are present at approximately 17 900 copies per haploid genome, and represent about 9.7% of the total genomic DNA. Twenty randomly chosen monomers have been sequenced. The deduced unambiguous consensus sequence is 277 bp long, and displays an A + T content of 54.2%. The monomers are very homogenous in sequence, showing on average 2.4% divergence from their consensus. Therefore, it is hypothesized that this repeated family may have recently appeared in the genome of the nematode, through some extensive amplification burst. Using a cloned monomer as a probe, dot‐blot experiments demonstrated the species‐specific distribution of the Bgl II satellite DNA. Moreover, squash‐blot assays allowed us to detect single M. exigua individuals, at any developmental stage, and even within root tissues, without the need for preliminary DNA purification. From these results, it is concluded that the procedure described, using the satellite DNA as a sensitive species‐specific probe, should constitute an improved and accurate diagnosis method for the detection and identification of the nematode, which would contribute to the implementation of targeted pest management strategies in all coffee growing countries of South and Central America.