Ralstonia solanacearum Strains from Martinique (French West Indies) Exhibiting a New Pathogenic Potential

We investigated a destructive pathogenic variant of the plant pathogen Ralstonia solanacearum that was consistently isolated in Martinique (French West Indies). Since the 1960s, bacterial wilt of solanaceous crops in Martinique has been caused primarily by strains of R. solanacearum that belong to either phylotype I or phylotype II. Since 1999, anthurium shade houses have been dramatically affected by uncharacterized phylotype II strains that also affected a wide range of species, such as Heliconia caribea, cucurbitaceous crops, and weeds. From 1989 to 2003, a total of 224 R. solanacearum isolates were collected and compared to 6 strains isolated in Martinique in the 1980s. The genetic diversity and phylogenetic position of selected strains from Martinique were assessed (multiplex PCRs, mutS and egl DNA sequence analysis) and compared to the genetic diversity and phylogenetic position of 32 reference strains covering the known diversity within the R. solanacearum species complex. Twenty-four representative isolates were tested for pathogenicity to Musa species (banana) and tomato, eggplant, and sweet pepper. Based upon both PCR and sequence analysis, 119 Martinique isolates from anthurium, members of the family Cucurbitaceae, Heliconia, and tomato, were determined to belong to a group termed phylotype II/sequevar 4 (II/4). While these strains cluster with the Moko disease-causing strains, they were not pathogenic to banana (NPB). The strains belonging to phylotype II/4NPB were highly pathogenic to tomato, eggplant, and pepper, were able to wilt the resistant tomato variety Hawaii7996, and may latently infect cooking banana. Phylotype II/4NPB constitutes a new pathogenic variant of R. solanacearum that has recently appeared in Martinique and may be latently prevalent throughout Caribbean and Central/South America.     

Ralstonia solanacearum strains from Martinique (French West Indies) exhibiting a new pathogenic potential

We investigated a destructive pathogenic variant of the plant pathogen Ralstonia solanacearum that was consistently isolated in Martinique (French West Indies). Since the 1960s, bacterial wilt of solanaceous crops in Martinique has been caused primarily by strains of R. solanacearum that belong to either phylotype I or phylotype II. Since 1999, anthurium shade houses have been dramatically affected by uncharacterized phylotype II strains that also affected a wide range of species, such as Heliconia caribea, cucurbitaceous crops, and weeds. From 1989 to 2003, a total of 224 R. solanacearum isolates were collected and compared to 6 strains isolated in Martinique in the 1980s. The genetic diversity and phylogenetic position of selected strains from Martinique were assessed (multiplex PCRs, mutS and egl DNA sequence analysis) and compared to the genetic diversity and phylogenetic position of 32 reference strains covering the known diversity within the R. solanacearum species complex. Twenty-four representative isolates were tested for pathogenicity to Musa species (banana) and tomato, eggplant, and sweet pepper. Based upon both PCR and sequence analysis, 119 Martinique isolates from anthurium, members of the family Cucurbitaceae, Heliconia, and tomato, were determined to belong to a group termed phylotype II/sequevar 4 (II/4). While these strains cluster with the Moko disease-causing strains, they were not pathogenic to banana (NPB). The strains belonging to phylotype II/4NPB were highly pathogenic to tomato, eggplant, and pepper, were able to wilt the resistant tomato variety Hawaii7996, and may latently infect cooking banana. Phylotype II/4NPB constitutes a new pathogenic variant of R. solanacearum that has recently appeared in Martinique and may be latently prevalent throughout Caribbean and Central/South America.     

Genetic diversity of Burkholderia solanacearum (synonym Pseudomonas solanacearum) race 3 in Kenya.

Genetic diversity among isolates of the bacterial plant pathogen Burkholderia solanacearum (synonym Pseudomonas solanacearum) race 3 biovar II of Kenya was determined by PCR with repetitive sequences (ERIC and BOX repetitive primer sets) and pulsed-field gel electrophoresis of genomic DNA digested by rare-cutting restriction endonucleases (RC-PFGE). The study comprised 46 isolates collected during 1992 from the major potato-growing regions of Kenya (45 were identified as race 3 biovar II, and 1 belonged to race 3 biovar N2) and 39 reference isolates from 19 other countries. RC-PFGE identified 10 distinct profile types among the Kenyan race 3 biovar II isolates (29 of the isolates exhibited identical profiles) and a further 27 distinct profile types among the reference isolates. ERIC and BOX primer sets were unable to differentiate race 3 biovar II isolates within the Kenyan population but differentiated a further two distinct profile types among the reference isolates. The race 3 biovar N2 isolate had a highly distinct RC-PFGE and repetitive sequence PCR profile. Statistical analysis of the data identified biogeographic trends consistent with conclusions drawn from previous studies on the origin and worldwide dissemination of race 3 biovar II isolates; however, genomic fingerprinting by RC-PFGE revealed a level of genetic diversity previously unrealized.     

Pasture populations of cattle nematode larvae in Guadeloupe (French West Indies)

The development of numbers of third-stage (L3) larvae of gastrointestinal nematodes after pat (faeces) deposition by heifers is described, using a mathematical model, for seven experiments carried out in Guadeloupe (French West Indies). A dramatic rise in L3 population size occurred on herbage near pats, 17-25 days after pat deposition. There was no clear relationship between climatic data and L3 population dynamics. However, 5 successive days of rainfall induced the resumption of larval migration in two experiments. Changing the unit of expression of L3 population size (100 L3 m-2 vs 1000 L3 per kg DM) did not alter estimates of the model parameters. The evolution of L3 population of Haemonchus and Cooperia were similar.     

EpsR Modulates Production of Extracellular Polysaccharides in the Bacterial Wilt Pathogen Ralstonia (Pseudomonas) solanacearum

Ralstonia solanacearum is the causal agent of bacterial wilt of many agriculturally important crops. Exopolysaccharide synthesized by products of the epsI operon is the major virulence factor for R. solanacearum. Expression of epsI has been demonstrated to be under the control of several proteins, including several two-component regulators. Overexpression of EpsR was found previously to reduce the amount of synthesis specifically from the epsI promoter. Here we present data that a single chromosomal copy of epsR activates the epsI promoter, suggesting that EpsR is a concentration-dependent effector of epsI gene expression. Furthermore, the ability of EpsR to modulate epsI expression is dependent on the phosphorylation state of EpsR. Gel mobility shift assays suggest that EpsR can specifically bind the epsI promoter and that this binding requires a phosphorylated form of EpsR.     

Acetylcholinesterase and ethoxyresorufin-o-deethylase in the surgeonfish Acanthurus bahianus around Martinique Island (French West Indies)

The biochemical indicators of biological effects of pollutants, ethoxyresorufin-edeethylase (EROD) and acetylcholinesterase (AChE), were measured in Acanthurus bahianus from 10 stations around Martinique Island (French West Indies). Strong induction of EROD was demonstrated in the bay of Fort de France in relation to organic pollution. Depression of AChE may suggest that neurotoxic compounds are having some effects along the east coast.     

Spatial and Temporal variations of mangrove fish assemblages in Martinique (French West Indies)

A study of the mangrove fish fauna in a bay of Martinique Island (French West Indies) was carried out at different seasons during two consecutive years. fishes were sampled with specific hoop-nets in the coastal areas at 8 stations.A total of 87 species was collected in the bay. Most individuals were represented by small-size specimens and juveniles. The overall species richness varied according to the stations and the sampling periods. The biomass and number of individuals were variable according to the location but remained stable in time. A factor correspondence analysis and a hierarchical clustering with median links were used to follow the evolution of the stations in space and time. Two types of stations were differentiated: the stations characterized by the mangrove and those under the influence of seagrass beds. A seasonal cycle, opposing the dry periods to the others, was observed.Thus, it seems that the use of the mangrove habitat by the fishes is optimized through a complete reorganization of communities in terms of species composition whereas the overall number and biomass remain stable. This model remains valid even for the most constraining biota of the mangrove ecosystem inhabited by a small number of well adapted species.     

Acetylcholinesterase and ethoxyresorufin-o-deethylase in the surgeonfish Acanthurus bahianus around Martinique Island (French West Indies)

Abstract

The biochemical indicators of biological effects of pollutants, ethoxyresorufin-edeethylase (EROD) and acetylcholinesterase (AChE), were measured in Acanthurus bahianus from 10 stations around Martinique Island (French West Indies). Strong induction of EROD was demonstrated in the bay of Fort de France in relation to organic pollution. Depression of AChE may suggest that neurotoxic compounds are having some effects along the east coast.     

Nine new species of Dichogaster (Oligochaeta, Megascolecidae) from Guadeloupe (French West Indies)

Nine species belonging to two distinct groups within the genus Dichogaster Beddard, 1888 are described from material collected on the volcanic section of the island of Guadeloupe. The species Dichogaster arborea, D. caesitifusca, D. callaina, D. girija and D. basseterrensis all inhabit the leaf tanks of bromeliads and share the following anatomical characteristics: spermathecal pores on the trailing edges of segments, spermathecal axis differentiated into ampulla, internally fluted central chamber and duct, penial setae long and slender, testes and funnels free, prostomium undivided or divided by two grooves, simple single typhlosole and a pair of dorsal caeca on the mid-intestine. Dichogaster athena also inhabits bromeliads, but lacks the above characteristics and male reproductive organs, and is more similar to the remaining species. The three remaining species, D. guadeloupensis, D. matoubensis and D. musciphila , with lateral typhlosoles, no intestinal caeca, simpler spermathecal structure, prostomiums divided by a single groove and short penial setae, all inhabit soils of montane forests. The division of Dichogaster based on muscularity of the proventriculus wall is shown to be unsupportable, since thickness of the wall is size-related.     

The phylogeny of the genus Indoplanorbis (Gastropoda,Planorbidae) from Africa and the French West Indies

Indoplanorbis exustus is a freshwater snail known as the intermediate host of various trematode parasites, including different species of the genus Schistosoma. Although its genetic diversity is well described in Asia, the phylogenetic diversity of strains from Africa and Guadeloupe (French West Indies) and their relationship to Asian and South‐East Asian strains remain unknown. To tackle this issue, we sampled individuals from Africa and Guadeloupe, and we computed phylogenetic reconstructions using five molecular markers: partial sequences of two mitochondrial genes, cox1 and 16S, and three nuclear markers, ITS1, ITS2 (Internal Transcribed Spacer 1 and 2) and 5.8S. Our results suggest that strains in Africa and Guadeloupe come from Asia and that they all belong to a single clade that is widespread around the globe.     

Introduction and spread of Thiara granifera (Lamarck, 1822) in Martinique, French West Indies

We followed the invasion dynamics of the Oriental thiarid snail Thiara granifera on the Martinique island, French Antilles. This freshwater species was first discovered in 1991 in the Charpentier River, and its spread has since been analysed based on a yearly survey of the malacological fauna at more than 100 sites covering the whole island and representing 50 river systems and three pools. Four river systems were sampled at many sites. Thirteen river systems were colonized by 1997. Colonization within river systems occurred at a speed greater than 1km per year, probably resulting from both active and passive dispersal. Our results can, on the whole, be explained by a simple diffusion process. However, stratified diffusion has to be invoked in at least one river. Moreover, colonization was faster downstream than upstream, suggesting that current velocity plays a significant role in dispersal. Dispersal also occurred between river systems at a mean distance of almost 10km, though with a large variance, in accordance with the scattered colony model of stratified diffusion. The relative frequencies of T. granifera and Melanoides tuberculata, another recent invader of Martinique, were followed at three sites on the Lézarde River. The first species quickly outnumbered the second, though never wiped it out. The data therefore do not support any exclusion phenomena between these two parthenogenetic invaders. Our analysis does not indicate any obvious influence of the rise of T. granifera on the local freshwater fauna.     

Allelic frequency variations at the MDH-1 locus within Schistosoma mansoni strains from Guadeloupe (French West Indies): ecological interpretation

1. An isoenzymatic study on Schistosoma mansoni from Guadeloupe has been carried out using isoelectric focusing in polyacrylamide gels. 2. Among the seven systems examined (LDH, MDH, G6PD, PGI, PGM, AcP, HK), only MDH showed variation at the MDH-1 locus and mdh-1a allele frequencies were used to characterise eight strains derived either from human or murine hosts, and representative of different transmission sites. 3. In comparison with criteria previously employed to type these strains (ecological context of their transmission sites, cercarial emergence patterns), mdh-1a frequency variations have been correlated to the degree of participation of the murine host reservoir in the parasite transmission dynamics within the different foci of Guadeloupe.     

Phytochemical study of Capraria biflora L. aerial parts (Scrophulariaceae) from Martinique island (French West Indies)

Aerial parts of Capraria biflora L. were collected in Martinique (French West Indies) and extracted by methanol. Two original chlorinated iridoids, 3-hydroxymyopochlorin (1) and 5-hydroxyglutinoside (2) were isolated by CPC (centrifugal partition chromatography) and characterized from the extract together with five known iridoid glycosides (3–7), two flavonoid glucuronides (8–9) and the phenylethanoid glycoside verbascoside (10). The structure of these compounds together with their relative configuration was established by spectroscopic data including in particular 1D and 2D NMR experiments (HSQC, HMBC, NOESY) and HRESIMS. Preliminary antibacterial evaluation of 1, 2 and 3 against a panel of Gram-positive and Gram-negative strains has been performed.     

Index Pteridophytorum Guadalupensium or a revised checklist to the ferns and club mosses of Guadeloupe (French West Indies)

Recent revision of the fern diversity of the French Caribbean island of Guadeloupe and its dependencies (Marie Galante, Les Saintes and La Désirade) resulted in the listing of 292 native ferns and club mosses in 28 families and 88 genera, of which eight ferns are endemic to Guadeloupe and 20 taxa are only recorded from the Lesser Antilles. Additionally, 21 species have recently been found to be naturalized. Nineteen new combinations are made and a new hybrid is described. Many types from the Fée collection have been reassessed and a number of names are lecto‐ or neotypified. Studied specimens are cited and localities are provided. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 161 , 213–277.     

Temporal Variation in Genetic Diversity and Structure of a Lotic Population of Burkholderia (Pseudomonas) cepacia

The genetic structure and temporal patterns of genetic diversity in a population of Burkholderia (Pseudomonas) cepacia, isolated from a southeastern blackwater stream, were investigated by multilocus enzyme electrophoresis. Allelic variation in seven structural gene loci was monitored at a single stream location at 0, 6, 12, and 24 h and at 2, 4, 8, 16, and 32 days. Over the length of the study, 217 isolates were collected, from which 65 unique electrophoretic types (ETs) were identified. Most of these ETs were present at only one or two time periods and were considered transients; however, one resident ET was particularly abundant (64 of the 217 isolates [29.4%]) and was found at all time points except day 32. The mean genetic diversity of the entire population was 0.520, and the index of association (a measure of multilocus linkage disequilibrium) was 1.33. These results, taken in conjunction with a previous study focusing on spatial patterns of genetic diversity in lotic B. cepacia, show that these bacterial populations exhibit greater variability among sites than within a site over time, suggesting relative stability over short time periods.     

New taxa of Malpighia (Malpighiaceae) from Mexico and the West Indies

Malpighia romeroana var.nayaritensis is described from Nayarit, México, andM. albiflora subsp.antillana andM. nummulariifolia subsp.oblongifolia from the West Indies.     

Population evolution of the free-living stage of goat gastrointestinal nematodes on herbage under tropical conditions in Guadeloupe (French West Indies)

In Guadeloupe (French West Indies), paddocks were contaminated with gastrointestinal helminth eggs by young goats during the rainy season and the dry season. The evolution of L3 population size on herbage was followed over a period of 56 days. The major genera were Haemonchus and Trichostrongylus. It was shown that the L3 appeared on herbage 7-14 days after the beginning of contamination (DAC), and the L3 population sizes were maximal between the 14th and the 21st DAC. The maximum duration of larval survival ranged between 49 and 56 days. There was a marked depressive effect by the dry season on eggs hatching and L3 development with some arrested egg hatching in Trichostrongylus. The climatic events and the amount of dry matter on pastures during the grazing period appeared as the main important factors which could interfere with the overall evolution of the L3 population size and there was no preferential direction of L3 migration from faeces to herbage.