Biduth Kundu

Reliable species-level information on elasmobranchs (sharks, rays, and skates) in the Arabian Gulf remains limited, despite these fish being among the most threatened marine vertebrates. Taxonomic uncertainty, driven by morphological similarities and incomplete reference datasets, continues to hinder accurate biodiversity assessments in the region. In this study, NADH dehydrogenase subunit 2 (NADH2) gene sequences were analyzed to assess the taxonomic status of elasmobranchs in United Arab Emirates waters, based on 182 specimens representing 31 species (15 sharks and 16 batoids) across 12 families. Shark lineages were consistently recovered and matched closely with published references, indicating a stable taxonomy. Batoids (rays), however, showed greater complexity, including misidentification among morphologically similar taxa, gaps in available reference sequences, and signs of possible cryptic diversity, reflecting persistent challenges in species identification and the need for more comprehensive molecular resources. Our findings highlight the value of genetic approaches in improving taxonomic resolution and establishing robust biodiversity baselines. Expanding reference databases, applying multi-locus genomic approaches, and broadening regional sampling will be essential to refining taxonomic frameworks and informing conservation management for elasmobranchs in the Arabian Gulf.

Background: Plant microbiomes can contribute to host adaptation in extreme environments, particularly deserts where high temperatures, intense radiation, water limitation, and nutrient-poor soils constrain plant survival. Citrullus colocynthis is a desert-adapted cucurbit with medicinal and agricultural relevance, yet integrated understanding of its microbiome across seasons, tissues, habitats, and functional traits remains limited. Here, we asked whether spatiotemporal microbiome dynamics in C. colocynthis are linked to microbial functional potential and cultivable traits relevant to persistence under arid conditions. Results: To address this, we profiled the microbiome of C. colocynthis across two sites, two seasons, and multiple compartments using 16S rRNA amplicon screening, shotgun metagenomics, culture-based phenotyping, and genome analysis. Amplicon profiling provided an exploratory framework and showed that plant-associated bacterial communities were shaped primarily by season and tissue type, with roots emerging as the most season-responsive compartment. Shotgun metagenomics confirmed stronger seasonal restructuring in root bacterial communities than in leaves and extended taxonomic profiling to fungal and archaeal fractions, which were interpreted descriptively because of low read representation. Summer root communities were enriched in actinobacterial genera, including Saccharopolyspora , Amycolatopsis , Pseudonocardia , and Nonomuraea , while functional profiling indicated coordinated shifts in central metabolism, cofactor salvage, exopolysaccharide-related pathways, and redox-associated functions. Twenty-four cultured bacterial isolates exhibited diverse stress-tolerance and plant growth-promoting traits, and whole-genome analyses identified biosynthetic, osmoprotective, oxidative-stress, and phytohormone-related gene content. Pangenome analysis of Pseudomonas orientalis revealed an open pangenome and lifestyle-associated accessory genes linked to host-associated functions. Conclusions: Together, these findings connect seasonal bacterial community turnover, metagenomic functional potential, and cultivable microbial traits in a desert plant holobiont, highlighting desert-native bacteria and pathways relevant to microbiome-guided strategies for arid agriculture.

The detrimental effects of ultraviolet C (UVC) radiation on living organisms, with a specific focus on the fruit fly Drosophila melanogaster, were examined. This study investigated the impact of heightened UVC radiation exposure on D. melanogaster by assessing mortality and fertility rates, studying phenotypic mutations, and investigating the associated molecular mechanisms. The findings of this study revealed that UVC radiation increases mortality rates and decreases fertility rates in D. melanogaster. Additionally, phenotypic wing mutations were observed in the exposed flies. Furthermore, the study demonstrated that UVC radiation downregulates the expression of antioxidant genes, including superoxide dismutase (SOD), manganese-dependent superoxide dismutase (Mn-SOD), zinc-dependent superoxide dismutase (Cu-Zn-SOD), and the G protein-coupled receptor methuselah (MTH) gene. These results suggest that UVC radiation exerts a destructive effect on D. melanogaster by inducing oxidative stress, which is marked by the overexpression of harmful oxidative processes and a simultaneous reduction in antioxidant gene expression. In conclusion, this study underscores the critical importance of comprehending the deleterious effects of UVC radiation, not only to safeguard human health on Earth, but also to address the potential risks associated with space missions, such as the ongoing Emirate astronaut program.

Background and Aim: Viruses are important components of the microbiome of ticks. Ticks are capable of transmitting several serious viral diseases to humans and animals. Hitherto, the composition of viral communities in Hyalomma dromedarii ticks associated with camels in the United Arab Emirates (UAE) remains unexplored. This study aimed to characterize the RNA virome diversity in male and female H. dromedarii ticks collected from camels in Al Ain, UAE. Materials and Methods: We collected ticks, extracted, and sequenced RNA, using Illumina (NovaSeq 6000) and Oxford Nanopore (MinION). Results: From the total generated sequencing reads, 180,559 (~0.35%) and 197,801 (~0.34%) reads were identified as virus-related reads in male and female tick samples, respectively. Taxonomic assignment of the viral sequencing reads was accomplished based on bioinformatic analyses. Further, viral reads were classified into 39 viral families. Poxiviridae, Phycodnaviridae, Phenuiviridae, Mimiviridae, and Polydnaviridae were the most abundant families in the tick viromes. Notably, we assembled the genomes of three RNA viruses, which were placed by phylogenetic analyses in clades that included the Bole tick virus. Conclusion: Overall, this study attempts to elucidate the RNA virome of ticks associated with camels in the UAE and the results obtained from this study improve the knowledge of the diversity of viruses in H. dromedarii ticks. Keywords: camels, Hyalomma dromedarii, nanopore technology, UAE, viral diversity, virome analysis, whole genome sequencing.

Citrullus colocynthis grows in the sandy desert soil of the Arabian Peninsula with limited access to water, aside from occasional precipitation or dew. Understanding its ability to produce water-filled fruit and nutrient-rich seeds despite the harsh environment, can be useful for agricultural applications. However, information regarding the microbiome of C. colocynthis is lacking. We hypothesized that C. colocynthis associates with bacteria that aid its survival, like what has been observed in other desert plants. Here, we used 16S rRNA gene data to gain insight into the microbiome of C. colocynthis to identify its associated bacteria. In total, 9818 and 6983 OTUs were generated from root, soil, and leaf samples combined. Overall, bulk soils had the highest alpha diversity, followed by rhizosphere and root zone soils. Furthermore, C. colocynthis is associated with known plant-growth-promoting bacteria (including Acidobacteria, Bacterioidetes, and Actinobacteria), and interestingly a class of non-photosynthetic Cyanobacteria (Melainabacteria) that is more abundant on the inside and outside of the root surface than control samples, suggesting its involvement in the rhizophagy process. This study will provide a foundation for functional studies to further understand how C. colocynthis-microbes interactions help them grow in the desert, paving the path for possible agricultural applications.

The mimosoid legumes are a clade of ~40 genera in the Caesalpinioideae subfamily of the Fabaceae that grow in tropical and subtropical regions. Unlike the better studied Papilionoideae, there are few genomic resources within this legume group. The tree Prosopis cineraria is native to the Near East and Indian subcontinent, where it thrives in very hot desert environments. To develop a tool to better understand desert plant adaptation mechanisms, we sequenced the P. cineraria genome to near-chromosomal assembly, with a total sequence length of ~691 Mb. We predicted 77,579 gene models (76,554 CDS, 361 rRNAs and 664 tRNAs) from the assembled genome, among them 55,325 (~72%) protein-coding genes that were functionally annotated. This genome was found to consist of over 58% repeat sequences, primarily long terminal repeats (LTR-)-retrotransposons. We find an expansion of terpenoid metabolism genes in P. cineraria and its relative Prosopis alba, but not in other legumes. We also observed an amplification of NBS-LRR disease-resistance genes correlated with LTR-associated retrotransposition, and identified 410 retrogenes with an active burst of chimeric retrogene creation that approximately occurred at the same time of divergence of P. cineraria from a common lineage with P. alba~23 Mya. These retrogenes include many biotic defense responses and abiotic stress stimulus responses, as well as the early Nodulin 93 gene. Nodulin 93 gene amplification is consistent with an adaptive response of the species to the low nitrogen in arid desert soil. Consistent with these results, our differentially expressed genes show a tissue specific expression of isoprenoid pathways in shoots, but not in roots, as well as important genes involved in abiotic salt stress in both tissues. Overall, the genome sequence of P. cineraria enriches our understanding of the genomic mechanisms of its disease resistance and abiotic stress tolerance. Thus, it is a very important step in crop and legume improvement.

In order to assess the genomic landscape of the United Arab Emirates (UAE) mitogenome, we sequenced and analyzed the complete genomes of 232 Emirate females mitochondrial DNA (mtDNA) within and compared those to Africa. We investigated the prevalence of haplogroups, genetic variation, heteroplasmy, and demography among the UAE native population with diverse ethnicity and relatively high degree of consanguinity. We identified 968 mtDNA variants and high-resolution 15 haplogroups. Our results show that the UAE population received enough gene flow from Africa represented by the haplogroups L, U6, and M1, and that 16.8% of the population has an eastern provenance, depicted by the U haplogroup and the M Indian haplogroup (12%), whereas western Eurasian and Asian haplogroups (R, J, and K) represent 11 to 15%. Interestingly, we found an ancient migration present through the descendant of L (N1 and X) and other sub-haplogroups (L2a1d and L4) and (L3x1b), which is one of the oldest evolutionary histories outside of Africa. Our demographic analysis shows no population structure among populations, with low diversity and no population differentiation. In addition, we show that the transmission of mtDNA in the UAE population is under purifying selection with hints of diversifying selection on ATP8 gene. Last, our results show a population bottleneck, which coincides with the Western European contact (1400 ybp). Our study of the UAE mitogenomes suggest that several maternal lineage migratory episodes liking African–Asian corridors occurred since the first modern human emerges out of Africa.