In the dry regions of the Arabian Peninsula, such as Saudi Arabia, rangeland degradation and the decline of pasture species have significantly reduced phytomass production. The scarcity of grazing pastures has led to an expansion of alfalfa-irrigated fields, exacerbating the risk of water shortages. This study is the first to systematically evaluate the adaptability and production potential of Cenchrus ciliaris accessions in the arid environment of Saudi Arabia. The objective of this study is to evaluate the potential of buffelgrass (C. ciliaris) as an alternative to alfalfa in irrigated crop systems for livestock production and to assess its suitability for reintroduction into degraded rangelands to enhance forage production. For this purpose, accessions of C. ciliaris were collected from five different sites in northern Saudi Arabia (Aja, Jameen, Zaitoun, Gaed, and Industrial zone) to select the most vigorous ecotypes to be introduced in the degraded lands and/or to be used as irrigated forage crop. This study shows that under full irrigation (2500-3000 mm year⁻¹), alfalfa can produce 11.9 t ha⁻¹ to 22.6 t ha⁻¹ with a five-year average of 17 t ha⁻¹. However, C. ciliaris can produce 9.3–18.4 t ha⁻¹ with less water consumption than alfalfa (water supply is estimated at 400–500 mm year⁻¹). The average was about 14.1 t ha⁻¹. Our comparative study of these accessions showed that the Aja accession seemed to be the most salt tolerant, whereas the Jameen accession was the most well-developed, productive (18.4 t ha⁻¹), and overgrazing resistant accession (940.3 g plant⁻¹ after 3 cuts). Therefore, the Jameen accession is recommended for rangeland rehabilitation. In terms of chemical composition, C. ciliaris was less protein rich than alfalfa, but this can be compensated for by its high digestibility, estimated by neutral detergent fiber (NDF of 69.6%). This study identifies the Gaed and Jameen accessions as the most productive and grazing resistant, exhibiting drought and salt tolerance, making them suitable for use in irrigated systems to produce high green- and dry-matter yields or for reintroduction to rehabilitate degraded rangelands for rehabilitation purposes.

Catalases are crucial antioxidant enzymes that regulate plants responses to different biotic and abiotic stresses. It has been previously shown that the activities of durum wheat catalase proteins (TdCAT1) were stimulated in the presence of divalent cations Mn²⁺, Mg²⁺, Fe²⁺, Zn²⁺, and Ca²⁺. In addition, TdCAT1s can interact with calmodulins in calcium-independent manner, and this interaction stimulates its catalytic activity in a calcium-dependent manner. Moreover, this activity is further enhanced by Mn²⁺ cations. The current study showed that wheat catalase presents different phosphorylation targets. Besides, we demonstrated that catalase is able to interact with Mitogen Activated Proteins kinases via a conserved domain. This interaction activates wheat catalase independently of its phosphorylation status but is more promoted by Mn²⁺, Fe²⁺ and Ca²⁺ divalent cations. Interestingly, we have demonstrated that durum wheat catalase activity is differentially regulated by Mitogen Activated Proteins kinases and Calmodulins in the presence of calcium. Moreover, the V0 of the reaction increase gradually following the increasing quantities of Mn²⁺ divalent cations. Such results have never been described before and suggest i) complex regulatory mechanisms exerted on wheat catalase, ii) divalent cations (Mn²⁺; Mg²⁺; Ca²⁺ and Fe²⁺) act as key cofactors in these regulatory mechanisms.

Superoxide dismutase (SOD) enzymes form the first line of plant protection against reactive oxygen species (ROS) accumulation in cells. In this study, we recognised 14 AvSOD genes in the hexaploid oat (Avena sativa) genome, including nine AvCSDs, three AvFSDs, and two AvMSDs. Phylogenetic analysis revealed that AvSOD genes from oat and different other monocotyledonous and dicotyledonous plant species were clustered into two different groups based on the metallic binding domain. The predicted 3D protein structures revealed comparable conserved AvSOD protein configuration within groups. Interestingly, different hormonal and light-responsive cis-elements were identified in the promoters of AvSOD genes. Gene ontology annotation results validate the AvSODs role such as response to contrasting stress stimuli (ozone, light intensity, UV-B, metallic stress…), metal-ion binding activities, cellular oxidant detoxification activity, and different other cellular components. Expression profiling by real time quantitative PCR showed that 12 genes (AvCSD1, AvCSD2, AvCSD3, AvCSD4, AvCSD5, AvCSD6, AvCSD7, AvFSD1, AvFSD2, AvFSD3, AvMSD1, and AvMSD2) were strongly upregulated in response to different hormones (abscisic acid and salicylic acid) and/or abiotic stress (salinity, cold, and drought) treatments. Our data provides more knowledge of SOD genes in plants and information for advanced functional analyses of this antioxidant gene family in oat.

The cytotoxic, antioxidant, anticancer, and antibacterial properties of ethanolic extracts from Phragmanthera austroarabica is of interest. Plants of P. austroarabica were gathered from the southern Saudi Arabian region of Albaha. P. austroarabica extract was assessed using DPPH (2, 2-diphenyl-1-picrylhydrazyl). The German Collection of Microorganisms and Cell Cultures (DSMZ) cancer cell lines used in this investigation. The cytotoxic activity of P. austroarabica extract was explored against MCF-7 breast and A549 lung cancer cell lines, along with doxorubicin as a positive control. In both treated cells, P. austroarabica showed a remarkable activity via suppressing the cell’s survival. In terms of IC50 (concentration equivalent to a survival rate of 50%), MCF-7 breast cancer cells were more sensitive to P. austroarabica extract.) DPPH colorimetric assay was employed to assess the antioxidant properties of P. austroarabica extract, the antioxidant activity was increased along with increment of extract concentrations. The leaves aqueous extract of P. austroarabica inhibited the growth of S. aureus by 6.3±0.12 mm and 24±0.43 mm and 15±0.56 mm respectively for seed, leaf and stem at concentrations 50 μl. However, the same concentrations inhibited the growth of E. coli by 25±0.75, 0.00 mm and 24±0.18 mm, following the same order. Different superscript letters indicate means that are significantly different at level (p˂0.05). Minimal inhibitory concentrations (MIC) of P. austroarabica ethanolic extracts against the tested microorganisms were 1.5, 1.6 and 1.5, respectively for seed, leaf and stem against Staph. Aureus and were 1.2, 0.00 and 1.2, respectively for seed, leaf and stem against E. coli.

Mistletoes, particularly members of the family Loranthaceae, are obligate hemiparasitic plants that influence host-tree physiology and ecosystem functioning. In Saudi Arabia, their ecological effects and management requirements may vary with host identity, infestation severity, climatic conditions, and land-use context. This systematic review synthesizes the available literature on the diversity, distribution, host associations, ecological impacts, and management of mistletoes in the Kingdom. Six native Loranthaceae species are considered: Tapinanthus globiferus, Oncocalyx glabratus, O. schimperi, Phragmanthera austroarabica, Plicosepalus curviflorus, and P. acaciae. Available studies indicate that these species are associated primarily with mountainous and other suitable habitats, particularly in western and southwestern Saudi Arabia, although their distributions and host ranges differ. Mistletoes establish vascular connections with host plants through specialized haustoria, enabling the uptake of water and mineral nutrients. Under severe infestation or water-limited conditions, these interactions can contribute to host-tree stress, crown deterioration, and reduced productivity. Studies from Saudi Arabia and comparable arid environments have identified Vachellia and Juniperus species, as well as cultivated fruit trees, as relevant host groups. Mechanical removal and pruning are established management approaches, whereas the suitability of chemical and biological controls requires further evaluation under local environmental conditions. However, quantitative evidence on infestation severity, host mortality, economic losses, and long-term population dynamics in Saudi Arabia remains limited. Future research should prioritize systematic field monitoring, standardized infestation assessments, spatial distribution mapping, and evaluations of management effectiveness. Integrating species-specific biological knowledge with locally validated management practices could support the conservation and sustainable management of the Kingdom’s forest and agricultural resources.

The taxonomic status of Arbutus pavarii Pamp., a rare and geographically restricted species endemic to northeastern Libya, has long been debated, with some treatments considering it a synonym of A. unedo. To resolve this uncertainty, we applied an integrative molecular framework that combined multilocus DNA barcoding, phylogenetic inference, and multivariate statistical analyses. Five barcode loci—nrITS, matK, rbcL, trnH–psbA, and rps16—were analyzed using barcode-gap diagnostics, TaxonDNA identification tests, and single-locus and concatenated phylogenetic analyses. Barcode-gap analyses based on Kimura 2-parameter distances revealed clear and reproducible separation between intra- and interspecific variation for A. pavarii, particularly for nrITS and the concatenated multilocus dataset, whereas conserved plastid loci showed limited discriminatory power when used individually. Phylogenetic reconstructions consistently recovered A. pavarii as a strongly supported monophyletic lineage, distinct from A. unedo and other Mediterranean congeners, with congruent topologies across the nuclear, plastid, and combined datasets. Multivariate analyses, including principal component analysis and heatmap clustering, further corroborate the genetic cohesion and distinctiveness of A. pavarii samples. Collectively, these results provide robust molecular evidence supporting the recognition of Arbutus pavarii as a distinct evolutionary lineage, rather than an intraspecific variant of A. unedo. This study established a reproducible multilocus framework for species delimitation in Arbutus and highlighted the importance of integrating nuclear and plastid markers to resolve complex taxonomic relationships. The clarified taxonomic status of A. pavarii has important implications for biodiversity assessment and conservation planning in the Mediterranean region, particularly in the Cyrenaican floristic province.