C. Callejas

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.

Occurrence and variability of mycotoxigenicFusarium species associated to wheat and maize in the South West of Spain

The contamination of cereals with mycotoxins produced by species ofFusarium is an important risk to human and animal health. The toxigenic profile is different depending on theFusarium species considered and, in some species, differences can also be observed at intraspecific level. Information about the distribution and variability of the mycotoxigenicFusarium species allow prediction of the toxins that may occur and to devise control strategies. In this work, the occurrence of mycotoxigenicFusarium species associated to cereals was analysed in a wide sample of durum wheat fields (Triticum durum Desf.) and maize from the South West of Spain (Andalucía).F. equiseti, F. graminearum andF. culmorum were the most frequentFusarium species detected in wheat fields followed byF. sambucinum andF. avenaceum, whereas in the case of maize,F. verticillioides andF. proliferatum were the onlyFusarium species present. The relationships of the Spanish isolates from theF. equiseti, F. avenaceum andF. sambucinum species were analysed by nucleotide sequence comparison of a partial region of the Elongation Factor 1 alpha (EF-1α) with other sequences available in data bases. The results indicated thatF. avenaceum andF. equiseti showed high variability and that the SpanishF. equiseti isolates seemed to belong toF. equiseti type II.

Genetic polymorphism at the cytochrome oxidase I gene in mediterranean populations of Batrocera Oleae (Diptera: Tephritidae)

The tephritid Bactrocera oleae (Gmelin) is a harmful pest of olive crops that cause important agricultural and economic losses in the Mediterranean area where 90% of the world olive trees are cultivated. The knowledge of the genetic diversity in insect pest species populations is critical for decisions concerning appropriate control management strategies. In the present work, the genetic variability within and among 7 populations ‐five from Spain, one from Italy and one from Tunisia‐, was assessed by sequencing 1151 bp of the COI gene. A total of 21 haplotypes were observed. The intraspecific diversity was high, particularly in the Spanish populations (haplotype and nucleotide diversity 0.84 and 0.00137, respectively). However, the genetic differentiation among the populations was low in the case of Spanish ones (Fst between 0 and 0.041), and higher –and statistically significant– when comparing with the Italian and Tunisian samples. The haplotypes distribution and the PCoA analysis show three clear groups of populations: Spanish, Italian and Tunisian. The results might indicate the length of time elapsed since B. oleae became established in the Mediterranean region, the large effective sizes expected of its populations and the high gene flow among Iberian populations. The information could be relevant for integrated control programmes coordination.

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.

Update of genetic information for the white-clawed crayfish in Spain, with new insights into its population genetics and origin

The white-clawed crayfish is endemic to western and southern Europe and its populations have decreased over recent decades. Spanish populations are generally poorly represented in scientific reports and are usually studied only with a single molecular marker. Here, we use two mitochondrial markers (cytochrome oxidase subunit I and rDNA 16S genes) to examine levels and patterns of genetic structure across the range of the species’ distribution in Spain. Data reveal the existence of two main genetic groups of white-clawed crayfish in Spain with the Ebro basin as a possible contact zone. Processes occurred in historical and recent times, such as genetic drift and translocations, contribute greatly to this genetic structure. Levels of genetic variability and genetic structure of Spanish populations together with demographic inferences suggest that the species established in the Iberian Peninsula, at least since the Late Pleistocene. Knowing the true origin of the Spanish populations is crucial when deciding upon the management policies that should be followed. Given the lack of any clear evidence against its indigenous status, we propose that current protection and conservation measures should be maintained. From a management point of view, we suggest that Spanish population should be considered as a single evolutionary significant unit (ESU) with two management units (MUs) corresponding with the genetic clusters detected in the present study.

Fast discrimination (RAPD‐PCR) of the species forming the pest complex Aleurodicus dispersus–Lecanoideus floccissimus (Hom: Aleyrodidae)

Abstract:  The Aleurodicus dispersus–Lecanoideus floccissimus complex has become a very important agricultural pest in the Canaries. These species are not easily differentiated by their morphological characteristics. The aim of the present study was to obtain genetic markers to unambiguously distinguish both species of this complex. Thus, six random primers were employed to generate RAPD markers. Different RAPD profiles were observed for the different species. The analysis successfully identified 39 reproducible and specific markers for L. floccissimus and 51 for A. dispersus, i.e. bands present in all individuals of one species but never in the other. RAPD markers resulted a useful tool for discriminate both species. Early identification of species and also of biotypes is crucial when designing control strategies to avoid the spread of the pest and consequently the considerable economic losses it causes in tropical crops.

The white-clawed crayfish in Spain—reply to Clavero and Centeno-Cuadros

This short communication is only intended to point out briefly and objectively some of the comments, appreciations, and sometimes misinterpretations made by Clavero and CentenoCuadros in their criticism to our article on the phylogeography of the white-clawed crayfish in Spain, recently published in this journal. For those skilled in the discipline of phylogeography, it is well known to be a multidisciplinary science. Therefore, we disagree with the argument of monodisciplinary approach given by these authors. The work of Matallanas et al. 2016, as all our previous ones, has no intention, no bias, or directionality. It clearly aims what the title synthesizes, an update of genetic information for the white-clawed crayfish in Spain. To achieve this, we have been the first to use two mitochondrial markers, the longest so far used, in a wide and representative sample of Iberian crayfish. A sample of crayfish fromNorthern Italy was just used as outgroup. The design is, therefore, very suitable and appropriate for the question posed.