The Bemisia tabaci cryptic species contains 39 known mitotypes of which the B and Q are best recognized for having established outside their extant endemic range. In the 1980s, previously uncharacterized haplotype(s) of the B mitotype rapidly established in tropical and subtropical locales distant from their presumed center of origin, leading to displacement of several native mitotypes and extreme damage to crops and other vegetation particularly in irrigated agroecosystems. To trace the natural and evolutionary history of the invasive B haplotypes, a phylo-biogeographic study was undertaken. Patterns of single nucleotide polymorphisms (SNPs) and signatures potentially indicative of geographic isolation were investigated using a globally representative mitochondrial cytochrome oxidase I gene (mtCOI) sequence database. Eight haplotype groups within the North Africa-Middle East (NAFME) region were differentiated, NAFME 1–8. The NAFME 1–3 haplotypes were members of the same population that is associated with warm desert climate niches of the Arabian Peninsula and east coastal Africa-Ethiopia. The NAFME 4 and 5 haplotypes are endemic to warm and cold semi-arid niches delimited by the Irano-Turanian floristic region, itself harboring extensive biodiversity. Haplotypes 6 and 7 co-occurred in the Middle East along eastern Mediterranean Sea landmasses, while NAFME 8 was found to be endemic to Cyprus, Turkey, and desert micro-niches throughout Egypt and Israel. Contrary to claims that collectively, the B mitotype is invasive, NAFME 6 and 8 are the only haplotypes to have established in geographical locations outside of their zone of endemism.

: G-protein-coupled receptors (GPCRs) are membrane-bound proteins, which are responsible for the detection of extracellular stimuli and the origination of intracellular responses. Both glucagon and glucagon-like peptide-1 (GLP-1) receptors belong to G protein-coupled receptor (GPCR) superfamily. Along with insulin, glucagon and GLP-1 are critical hormones for maintaining normal serum glucose within the human body. Glucagon generally plays its role in the liver through cyclic adenosine monophosphate (cAMP), where it compensates for the action of insulin. GLP-1 is secreted by the L-cells of the small intestine to stimulate insulin secretion and inhibit glucagon action. Despite extensive research efforts and the multiple approaches adopted, the glycemic control in the case of type-2 diabetes mellitus remains a major challenge. Therefore, a deep understanding of the structure-function relationship of these receptors will have great implications for future therapies in order to maintain a normal glucose level for an extended period of time. The antagonists of glucagon receptors that can effectively block the hepatic glucose production, as a result of glucagon action, are highly desirable for the tuning of the hyperglycemic state in type 2 diabetes mellitus. In the same manner, GLP-1R agonists act as important treatment modalities, thanks to their multiple anti-diabetic actions to attain normal glucose levels. : In this review article, the structural diversity of glucagon and GLP-1 receptors along with their signaling pathways, site-directed mutations and significance in drug discovery against type-2 diabetes are illustrated. Moreover, the promising non-peptide antagonists of glucagon receptor and agonists of GLP-1 receptor, for the management of diabetes are presented with elaboration on the structure-activity relationship (SAR).

Begomoviruses (Geminiviridae) cause severe diseases in several crops, often causing significant losses due to reduced yield and quality. These viruses are easily transmitted by the whitefly (Bemisia tabaci) vector. Begomovirus-like symptoms were observed in wild poinsettia (Euphorbia cyathophora) and cultivated papaya (Carica papaya) plants in the Nizwa, Al-Dakhliya and Al-Batinah regions of Oman, where papaya is grown extensively. The aim of this study was to identify the suspected viral causal agent associated with yellow mosaic and leaf curl symptoms in the poinsettia and papaya plants. Symptomatic leaf samples were collected and subjected to DNA isolation followed by PCR amplification with begomovirus-coat protein specic primers. An amplicon of betasatellites was also amplified using betasatellite-specific primers. The amplicons were cloned and sequenced bi-directionally. The full-length begomoviral genome was determined to be 2766 and 2752 bp in length for the wild poinsettia and papaya isolates, respectively. The respective betasatellites were found to be 1354 and 1370 bp. Sequence analysis indicated that the papaya isolate, herein tomato yellow leaf curl virus (TYLCV)-Pap-Oman, shared 95.0% nucleotide identity with the wild poinsettia isolate, herein TYLCV-Poin-Oman, followed by 93.5% identity with TYLCV-Iran (GU076448). Phylogenetic analysis grouped TYLCV-Pap-Oman and TYLCV-Poin-Oman with TYLCV isolates previously reported from Iran, Saudi Arabia and Sudan, whereas the two betasatellites grouped them with TYLCB isolates previously reported from Oman. Based on the nucleotide sequence identity and phylogenetic tree analysis, the Begomovirus identified from papaya and wild poinsettia is considered an isolate of TYLCV from plant host species previously reported in the Arabian Peninsula.

This review article provides an in-depth analysis of the biological invasions of begomoviruses, focusing on a prominent case study involving the Tomato Yellow Leaf Curl Virus (TYLCV) and its vector, the whitefly Bemisia tabaci, in the unique agricultural landscape of Oman. Begomoviruses, known for their global impact on crop yields, have become a significant concern in Oman, posing a serious threat to the cultivation of various crops, particularly tomatoes. The review begins by exploring the molecular characteristics and ecological dynamics of TYLCV and Bemisia tabaci, shedding light on the intricate interactions between the virus, the vector, and the host plants. Through a comprehensive analysis of historical data and recent research findings, the article examines the patterns and pathways of invasion, elucidating the factors contributing to the successful establishment and spread of TYLCV in Oman. The impacts of TYLCV invasion on agricultural productivity and crop quality are critically evaluated, providing insights into the specific challenges faced by Omani farmers. Special attention is given to the socio-economic repercussions of TYLCV-induced crop losses, emphasizing the need for adaptive management strategies to mitigate the negative consequences on food security and rural livelihoods. Furthermore, the review assesses the current state of knowledge regarding the management and control of TYLCV and Bemisia tabaci in Oman. It discusses the successes and limitations of existing strategies, ranging from conventional practices to innovative biotechnological approaches, providing a foundation for future research directions and the development of sustainable management practices in the context of biological invasions of begomoviruses in Oman. Overall, this review contributes to a nuanced understanding of the complex interplay between invasive begomoviruses, their vectors, and local agricultural systems, offering valuable insights for researchers, policymakers, and practitioners engaged in crop protection and biosecurity in Oman and beyond.