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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.

Rhanterium eppaposum Oliv. (Arfaj) the national plant of Kuwait, is a perennial bushy shrub and the national flower of Kuwait. It is one of the most palatable forage plants and an excellent performer for desert rehabilitation. Due to several anthropogenic activities and climate change, this native plant has suffered severe degradation. In order to formulate conservation strategies, the genetic diversity of Rhanterium, was assessed by inter simple sequence repeat (ISSR) markers. A total of 93 wild landraces distributed in six remote locations in Kuwait were tested using 17 primers (PIC = 0.31; polymorphism = 92.8 %) that produced 195 unambiguous and reproducible bands. Overall, diversity indices were high enough (Nei’s gene diversity (h') - 0.286; Shannon’s diversity index - 0.414) for these populations. AMOVA test returned a fixation coefficient (FST) of 0.116 (p = 0.0) with higher genetic variations detected within (88 %) the populations as compared to among (12 %) the populations. Satisfactory levels of genetic differentiation (GST = 0.186; G’ST = 0.250; D’ = 0.295) were recorded for R. eppaposum with a gene flow (NM) maintained at 1.9. The maximum genetic distances were observed between Maqwa and Mina Abdulla (Ds- 0.158; FST- 0.228) whereas minimum was between Al Kabd and SANR (Ds - 0.06; FST- 0.05). A weak Mantel’s correlation (r2 - 0.139; P = 0.014) between the six populations was also recorded. A narrow population structure was observed through the PCoA (2 groups), STRUCTURE (2 groups, K = 2) and SPLIT decomposition (1 cluster). The high genetic diversity within the populations are encouraging, however the low genetic differentiation raises concerns. The population structure should be improved by planting genetically diverse genotypes in areas of very low diversity to broaden its genetic base. Keywords: Conservation management, Genetic diversity, Molecular markers, Arfaj, Polymorphism