Search

Haloxylon salicornicum Moq. Bunge ex Boiss (Rimth) is one of the main structural elements in Eastern Arabian vegetation associations. The plant is utilized as a food source for domestic stock, stabilizes the soil surface besides providing suitable microclimates for exotic species. It is considered one of the most promising species for re-vegetation. H. salicornicum community is under threat from overgrazing leading to a reduction in the percentage of distribution from 22.7% to 2.2% in Kuwait. Therefore, genome characterization of this important Kuwaiti plant is required to formulate strategies for its conservation. Here we report the draft of the H. salicornicum genome, which was sequenced on an Illumina HiSeq 2500 platform. BUSCO assessment revealed 69% of the genome was to be complete. Overall, 12960 gene structures, 11280 protein-coding genes, 11309 mRNAs (protein-coding), 51265 exons and 48100 CDSs were predicted. Functional annotation was carried out by interproscan-5.29-68.0. A total of 7222 protein-coding sequences were, annotated out of 11309 by at least one ontology term. All these genes were associated with 11 major biological processes branched into 60 child processes.

Kuwait is a country with a very high dust loading; in fact it bears the world’s highest particulate matter concentration in the outdoor air. The airborne dust often has associated biological materials, including pathogenic microbes that pose a serious risk to the urban ecosystem and public health. This study has established the baseline taxonomic characterization of microbes associated with dust transported into Kuwait from different trajectories. A high volume air sampler with six-stage cascade impactor was deployed for sample collection at a remote as well as an urban site. Samples from three different seasons (autumn, spring and summer) were subjected to targeted amplicon sequencing. A set of ~ 50 and 60 bacterial and fungal genera, respectively, established the core air microbiome. The predominant bacterial genera (relative abundance ≥ 1%) wereBrevundimonas(12.5%),Sphingobium(3.3%),Sphingopyxis(2.7%),Pseudomonas(2.5%),Sphingomonas(2.4%),Massilia(2.3%),Acidovorax(2.0%),Allorhizobium(1.8%),Halomonas(1.3%), andMesorhizobium(1.1%), and the fungal taxa wereCryptococcus(12%) followed byAlternaria(9%),Aspergillus(7%),Candida(3%),Cladosporium(2.9%),Schizophyllum(1.6%),Fusarium(1.4%),Gleotinia(1.3%) andPenicillium(1.15%). Significant spatio-temporal variations were recorded in terms of relative abundances, α-diversities, and β-diversities of bacterial communities. The dissimilarities were less pronounced and instead the communities were fairly homogenous. Linear discrimant analysis revealed three fungal genera known to be significantly differentially abundant with respect to different size fractions of dust. Our results shed light on the spatio-temporal distribution of airborne microbes and their implications in general health.

Haloxylon salicornicum moq. Bunge ex Boiss (Rimth) is one of the native plants of Kuwait, extensively depleting through the anthropogenic activities. It is important to conserve Haloxylon community in Kuwait as it can tolerate extreme adverse conditions of drought and salinity to be potentially used in the desert and urban revegetation and greenery national programs. Therefore, a set of 16 inter simple sequence repeat (ISSR) markers were used to assess genetic diversity and population structure of 108 genotypes from six locations in Kuwait. The ISSR primers produced 195 unambiguous and reproducible bands out of which 167 bands were polymorphic (86.5%) with a mean PIC value of 0.31. The overall average values of Nei's gene diversity (h') and Shannon's diversity index (I) were 0.254 and 0.375, respectively. Results of AMOVA revealed high genetic variations within populations (77.8%) and low among populations (22%). The values of Fixation index (FST = 0.22; P = 0.0), Genetic differentiation (GST = 0.262; G'ST = 0.327; D = 0.335 and Gene flow (NM = 0.880) were indicative of heterozygous populations. The results of STRUCTURE and split decomposition analysis suggested that the Rimth accessions of Kuwait can be grouped into five and six subpopulations, respectively. Principal coordinate analysis (PCoA) grouped them into three clusters. The pairwise Nei's genetic distances (DS) among populations demonstrated a narrow range from 0.047 to 0.187 (Scale-0.0 to 1.0). The Mantel's test revealed a weak correlation (r2- 0.188; P-0.013) between the genetic distance and geographic distances. Our results suggest that the narrowly distributed Haloxylon community in Kuwait demonstrated a high genetic diversity within the populations however the overall population structure was weak.

The role of rhizosphere microbial communities in the degradation of hydrocarbons remains poorly understood and is a field of active study. We used high throughput sequencing to explore the rhizosphere microbial diversity in the alfalfa and barley planted oil contaminated soil samples. The analysis of 16s rRNA sequences showed Proteobacteria to be the most enriched (45.9%) followed by Bacteriodetes (21.4%) and Actinobacteria (10.4%) phyla. The results also indicated differences in the microbial diversity among the oil contaminated planted soil samples. The oil contaminated planted soil samples showed a higher richness in the microbial flora when compared to that of untreated samples, as indicated by the Chao1 indices. However, the trend was different for the diversity measure, where oil contaminated barley planted soil samples showed slightly lower diversity indices. While the clustering of soil samples grouped the oil contaminated samples within and across the plant types, the clean sandy soil samples formed a separate group. The oil contaminated rhizosphere soil showed an enrichment of known oil-degrading genera, such as Alcanivorax and Aequorivita, later being specifically enriched in the contaminated soil samples planted with barley. Overall, we found a few well known oil-degrading bacterial groups to be enriched in the oil contaminated planted soil samples compared to the untreated samples. Further, phyla such as Thermi and Gemmatimonadetes showed an enrichment in the oil contaminated soil samples, indicating their potential role in hydrocarbon degradation. The findings of the current study will be useful in understanding the rhizosphere microflora responsible for oil degradation and thus can help in designing appropriate phytoremediation strategies for oil contaminated lands.