91 research outputs found
Application of RNA interference to root-knot nematode genes encoding esophageal gland proteins
International audienc
Interactions entre Spiroplasma citri et son insecte vecteur, la cicadelle Circulifer haematoceps : le double jeu de la phosphoglycérate kinase
National audienc
Direct identification and functional analysis of secretory proteins from the plant parasitic root-knot nematode
International audienc
Towards the proteome of Spiroplasma citri: setting up a 2-DE reference map
International audienc
Interaction between Spiroplasma citri and the actin cytoskeleton of its insect vector's salivary gland cells
International audienc
Deciphering the role of the Spiroplasma citri phosphoglycerate kinase in the spiroplasma internalization into its insect vector'cells
National audienc
Mise en évidence chez la cicadelle Circulifer haematoceps, de protéines potentiellement impliquées dans la transmission de Spiroplasma citri
National audienc
Cryptic haplotypes of "Candidatus Liberibacter africanus"
“Candidatus Liberibacter africanus” (Laf) has long been recognised as a causal agent of the devastating citrus disease huanglongbing (HLB) or citrus greening. This species is currently restricted to Africa, the Arabian Peninsula and some Indian Ocean islands and vectored by the African citrus psyllid, Trioza erytreae. Blotchy mottle on citrus leaves is characteristic of the disease. Somewhat similar symptoms in the Rutaceous tree Calodendrum capensis (Cape Chestnut) resulted in the discovery of Laf outside commercial citrus crops in South Africa. This was classed as a subspecies of Laf (capensis, hence LafC). In subsequent surveys of both commercial citrus crops and Calodendrum, both natural and ornamental specimens, LafC was not found in the citrus crop, nor has Laf been found in C. capensis. HLB was reported from Madagascar in 1968 but no sequences from this source have so far been published. Until fairly recently, only the reference 16S rRNA gene sequences of Laf (L22533) and LafC (AF137368) had been deposited in GenBank. Both of these reference sequences contain a number of unresolved nucleotides. Resolving these nucleotide positions by aligning against more recently available sequences, it becomes evident that these unresolved positions represent one percentage point difference in similarity between Laf and LafC. The originally reported 97.4% similarity is therefore incorrect based on this new information. Recalculating the similarity on the full length 16S rDNA sequence results in 99.54% similarity, a value too high to justify a subspecies status. LafC should therefore be reduced to that of a haplotype of Laf. Further, the six 16S rRNA gene sequences currently available in GenBank identified as the species Laf separate into 2 haplotype groups. The 3 haplotypes of Laf are therefore LafA designated as the first accession sequenced (L22533), LafC for the former capensis subspecies and to recognise the prior use of this term, and LafB for the third haplotype not previously recognised. Thus the cryptic presence of 3 haplotypes is revealed by this review of the Laf 16S rDNA sequences
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