Al Wahbah Crater, located in a remote area in western Saudi Arabia as part of The Harrat extinct volcanic chain, is 2 km wide with a depth of 250 m. It is registered by the General Commission for Tourism and National Heritage as an ancient and archaeological site. The crater is subjected to extreme environmental conditions as its bottom is rarely subjected to rainfall and mudflows. Because of high temperature, high evaporation rates and extremely limited rainfall, the crater leaves behind dried thick white sodium phosphate crystals. Here, we studied the chemical composition and the microbial community composition using 16S rRNA pyrosequencing in different vertical layers (2, 20, 40, 60, 80 and 100 cm) of the crater sediment. Total sodium concentrations were 28 000– 46 700 ppm and calcium levels were 31 400– 56 500 ppm. In addition, samples were very sulphuric, with sulphate and sulphite levels exceeding 2157 ppm and 5.54 ppm, respectively. Ferric ions concentrations were <0.2 ppm, while nitrate, ammonium and nitrite levels were <2 ppm, 1.5 ppm and 0.05 ppm, respectively. Archaea dominated the surface and the bottom, while bacteria were most common at 20–60 cm. Extremely halophilic archaea and bacteria including Halorhabdus spp. Halorubrum spp., Salinibacter iranicus and Halorhodospira halophila were identified in all samples. Moreover, the relative abundance of Halanaerobiaceae accounted for 22% of the species in the top of the crater. S. iranicus and species belonging to Halorhabdus and Halorubrum that were identified between 60 and 100 cm could be considered as extreme organisms.

Using a high-throughput 454 pyrosequencing approach a novel set of microsatellite markers was developed for one of the key grapevine insect pests, the European grapevine moth Lobesia botrana (Lepidoptera: Tortricidae). 20 primer pairs flanking a microsatellite motif were designed based on the sequences obtained and were subsequently evaluated in a sample of 14 L. botrana populations from Europe and the Middle East. 11 markers showed stable and reproducible amplification patterns; however, one of the 11 markers was monomorphic in all L. botrana populations analysed. Estimated frequencies of null alleles of more than 20% were evident for two of the markers tested, but varied substantially depending on the respective L. botrana population. In 12 of the 14 L. botrana populations observed heterozygosities were lower to those expected under Hardy–Weinberg equilibrium, indicating a deficiency of heterozygotes in the respective populations. The overall FST value of 0.075 suggested a moderate but significant genetic differentiation between the L. botrana populations included in this study. In addition, a clear geographic structure was detected in the set of samples, evident through a significant isolation by distance and through results from structure analysis. In structure analysis, L. botrana populations were grouped in two clearly separated clusters according to their European (Spain, Italy, Germany) or Middle Eastern (Israel, Syria, Turkey) origin. This novel set of microsatellite markers can now be applied to study the evolutionary ecology of this species including host shifts and host adaptation as well as spread of individuals across worldwide viticulture.

Although the poultry red mite Dermanyssus gallinae (De Geer, 1778) is the major parasitic pest in poultry farming causing substantial economic losses every year, nucleotide data are rare in the public databases. Therefore, de novo sequencing covering the transcriptome of D. gallinae was carried out resulting in a dataset of 232 097 singletons and 42 130 contiguous sequences (contigs) which were subsequently clustered into 24 140 isogroups consisting of 35 788 isotigs. After removal of sequences possibly originating from bacteria or the chicken host, 267 464 sequences (231 657 singletons, 56 contigs and 35 751 isotigs) remained, of which 10·3% showed homology to proteins derived from other organisms. The most significant Blast top-hit species was the mite Metaseiulus occidentalis followed by the tick Ixodes scapularis. To gain functional knowledge of D. gallinae transcripts, sequences were mapped to Gene Ontology terms, Kyoto Encyclopedia of Gene and Genomes (KEGG) pathways and parsed to InterProScan. The transcriptome dataset provides new insights in general mite genetics and lays a foundation for future studies on stage-specific transcriptomics as well as genomic, proteomic, and metabolomic explorations and might provide new perspectives to control this parasitic mite by identifying possible drug targets or vaccine candidates. It is also worth noting that in different tested species of the class Arachnida no 28S rRNA was detectable in the rRNA profile, indicating that 28S rRNA might consists of two separate, hydrogen-bonded fragments, whose (heat-induced) disruption may led to co-migration with 18S rRNA.