A genetic approach to Spanish populations of the threatened Austropotamobius italicus located at three different scenarios.

Spanish freshwater ecosystems are suffering great modification and some macroinvertebrates like Austropotamobius italicus, the white-clawed crayfish, are threatened. This species was once widely distributed in Spain, but its populations have shown a very strong decline over the last thirty years, due to different factors. Three Spanish populations of this crayfish--from different scenarios--were analysed with nuclear (microsatellites) and mitochondrial markers (COI and 16S rDNA). Data analyses reveal the existence of four haplotypes at mitochondrial level and polymorphism for four microsatellite loci. Despite this genetic variability, bottlenecks were detected in the two natural Spanish populations tested. In addition, the distribution of the mitochondrial haplotypes and SSR alleles show a similar geographic pattern and the genetic differentiation between these samples is mainly due to genetic drift. Given the current risk status of the species across its range, this diversity offers some hope for the species from a management point of view.

Vast Gene Flow among the Spanish Populations of the Pest Bactrocera oleae (Diptera, Tephritidae), Phylogeography of a Metapopulation to Be Controlled and Its Mediterranean Genetic Context.

Spain is the leading producer of olives and olive oil. Ninety-five percent of world production originate from Spain and other regions of the Mediterranean Basin. However, these olive-growing countries face a major problem, the harmful fly Bactrocera oleae, the main pest of olive crops. To improve its control, one of the challenges is the further knowledge of the species and populations dynamics in this area. A phylogeographic work is necessary to further characterise the levels and distribution patterns of genetic diversity of the Spanish populations and their genetic relationships with other Mediterranean populations. A 1151 bp fragment of the mitochondrial cytochrome oxidase subunit I (COI) gene has been analysed in over 250 specimens of the six main Mediterranean countries via sequencing. Genetic diversity parameters were high; 51 new haplotypes have been identified showing a geographical pattern across the Mediterranean area. The data revealed that olive fruit fly populations have been long time established in the Mediterranean Basin with two genetic groups. Gene flow seems to be the main process in shaping this genetic structure as well as fly's colonisation routes that have paralleled those of the olive tree.

Genetic variability and Fumonisin production by Fusarium proliferatum.

Fusarium proliferatum is together with Fusarium verticillioides the main source of fumonisins, a health risk mycotoxin, contaminating agro-products. Contrary to F. verticillioides, it colonizes a wide range of host plants besides maize, such as wheat or barley among others, in particular in certain regions (Southern Europe). The phylogenetic study performed in this work using a wide sample of isolates from diverse hosts and origins revealed a high variability, while no host preferences could be sustained. A real time RT-PCR assay was also developed specific for F. proliferatum on the basis on fumonisin biosynthetic gene, FUM1, which allowed discrimination from F. verticillioides. FUM1 gene expression showed a high and significant correlation (0.77) with fumonisin production, representing a valuable tool for specific and sensitive diagnosis of metabolically active fumonisin-producing F. proliferatum isolates and for evaluating the influence on environmental conditions on FUM1 gene regulation. The ability to produce fumonisins was also widely distributed indicating that F. proliferatum can represent a risk for health similarly to F. verticillioides. Moreover, the wide range of plants susceptible to colonization by F. proliferatum suggests that the impact of fumonisin risk in a number of commodities might need a revision.

Phylogeography of Organophosphate Resistant ace Alleles in Spanish Olive Fruit Fly Populations: A Mediterranean Perspective in the Global Change Context.

The olive fruit fly (olf) Bactrocera oleae is the most damaging olive pest. The intensive use of organophosphates (OPs) to control it, led to an increase in resistance in field populations. This study assesses the presence and distribution of three mutations at the ace gene related to target site insensitivity to OPs in Spain. Samples from other Mediterranean countries were included as external references. Resistance-conferring alleles (from exons IV and VII of the ace gene) reached almost an 80% frequency in olf Spanish populations. In total, 62% of them were homozygous (RR/RR), this being more common in eastern mainland Spain. High frequencies of RR/RR individuals were also found in North Mediterranean samples. Conversely, in Tunisia, only sensitive alleles were detected. Finally, the exon X mutation ∆Q3 had an extremely low frequency in all samples. The high frequency of genotype RR/RR in Spain indicates high fitness in an agroecosystem treated with pesticides, in contrast to ∆Q3. At exon IV all flies carried the same haplotype for the allele conferring resistance. The sequence analysis at this exon suggests a unique origin and fast expansion of the resistant allele. These results provide evidence that OPs appropriate use is needed and prompt the search for alternative methods for olf pest control.

A novel MFS transporter encoding gene in Fusarium verticillioides probably involved in iron-siderophore transport.

The major facilitator superfamily (MFS) is a ubiquitous group of proteins involved in the transport of a wide range of compounds, including toxins produced by fungal species. In this paper, a novel MFS encoding gene (Fusarium iron related gene or FIR1), which had shown an up-regulation in fumonisin-inducing conditions, has been identified and characterized. The deduced protein sequence, which predicted 14 transmembrane domains typical of MFS transporters and its phylogenetic relationships with representative members of MFS transporters suggested a possible function of FIR1 as a siderophore transporter. A real-time RT-PCR protocol has been developed to analyse the expression pattern of the FIR1 gene in relation to siderophore production. The results indicated that the synthesis of extracellular siderophores by F. verticillioides observed in absence of extracellular iron was repressed in iron-supplemented cultures and showed a good correspondence with FIR1 gene expression. However, the pattern of FIR1 gene expression observed suggested that this gene did not seem to be functionally related to fumonisin production.