Mansour Hassan, Alsamadany Hameed, Al-Hasawi Zaki M
Department of Biological Sciences, College of Science & Arts, King Abdulaziz University, Rabigh 21911, Saudi Arabia.
Department of Botany, Faculty of Science, Suez Canal University, Ismailia 41522, Egypt.
Plants (Basel). 2022 Jun 13;11(12):1560. doi: 10.3390/plants11121560.
Oliv. is a perennial medicinal shrub growing mainly in desert habitats in the Arabian Peninsula. In western Saudi Arabia, the remaining few populations of this species are exposed to many threats, including overcutting, overgrazing, and recently, increasing human activities. These threats are predicted to be exacerbated by the advancement of aridification caused by climate change. The conservation and recovering of the diminished populations of necessitate measurement of their genetic diversity and genetic differentiation. To accomplish this objective, we tested 150 simple sequence repeat (SSR) primer pairs, with which 40 polymorphic loci were identified. These polymorphic loci were used to determine the population genetics of 540 plant accessions sampled from a total of 45 populations of located in 8 sites in western Saudi Arabia: Wadi Khurieba, Wadi Al Khamas, Gebel Al Twaal, Al Asaafer, Wadi ALHamda, Wadi Al Nassayeif, Wadi Qaraba, Wadi Kuliayah, and Wadi Dahban. Low levels of genetic diversity were found in all populations (the values of the ranged between 52.5 and 15) along with a declined value of (0.123) and a considerable inbreeding value ( = 0.942), which confirmed a noticeable shortage of heterozygotes. High genetic differentiation among the populations and a low value of gene flow are indicative of high isolation among the populations, which has caused a severe deficiency in gene migration. The data obtained herein inspire several recommendations for conservation and retrieval of the existing populations, including seed banks, restoration of diminished populations, and monitoring and prevention of cutting and grazing activities at threatened sites. All of these measures are urgently required to avoid imminent extinction.
油橄榄是一种多年生药用灌木，主要生长在阿拉伯半岛的沙漠栖息地。在沙特阿拉伯西部，该物种仅存的少数种群面临着诸多威胁，包括过度砍伐、过度放牧，以及最近日益增加的人类活动。预计气候变化导致的干旱化加剧将使这些威胁进一步恶化。保护和恢复数量减少的种群需要测量其遗传多样性和遗传分化。为实现这一目标，我们测试了150对简单序列重复（SSR）引物对，从中鉴定出40个多态性位点。这些多态性位点用于确定从沙特阿拉伯西部8个地点的45个种群中采集的540份植物样本的群体遗传学，这些地点包括：胡里耶巴谷、哈马斯谷、图瓦尔山、阿萨费尔、哈姆达谷、纳西耶夫谷、卡拉巴谷、库利亚亚谷和达班谷。所有种群的遗传多样性水平都较低（观测杂合度值在52.5至15之间），同时固定指数值下降（0.123）且存在相当程度的近亲繁殖值（0.942），这证实了杂合子明显短缺。种群间的高遗传分化和低基因流值表明种群间隔离程度高，这导致了基因迁移的严重不足。本文获得的数据为现有种群的保护和恢复提出了多项建议，包括种子库、恢复数量减少的种群，以及监测和防止受威胁地点的砍伐和放牧活动。所有这些措施都迫切需要实施，以避免该物种即将灭绝。
