Botany Department, Faculty of Science, Mansoura University, Mansoura, 35516, Egypt.
Botany Department, Faculty of Science, Tanta University, Tanta, 31527, Egypt.
BMC Plant Biol. 2022 Aug 1;22(1):383. doi: 10.1186/s12870-022-03768-6.
Alhagi maurorum Medik. (camelthorn) is a dominant desert plant indigenous in various habitats, including the Western Desert of Egypt. The plant is especially prevalent in and around economic iron ore deposits. Nutrient and heavy metal levels in A. maurorum tissues and soil samples were assessed to identify associations between heavy metal levels in plants and soil. The objective was to evaluate this species as an indicator of heavy metal pollution. Photosynthetic pigments, protein, proline, alkaloids, flavonoids, 2,2-diphenyl-1-picrylhydrazylscavenging, reduced glutathione, malondialdehyde, antioxidant enzymes, and stress-related gene expression were assessed to determine their functional roles in metal stress adaptation in ultra- and molecular structure. Additionally, the molecular genetic variation in A. maurorum samples was assessed using co-dominant sequence-related amplified polymorphism (SRAP) and inter simple sequence repeats (ISSR).
A substantial difference in enzymatic and non-enzymatic antioxidants of A. maurorum was observed in samples collected from three sites. A. maurorum is suited to the climate in mineralized regions. Morphologically, the stem shows spines, narrow leaves, and a reduced shoot system. Anatomically, modifications included a cuticle coating on leaves and stems, sunken stomata, a compact epidermis, and a thick cortex. Significant anatomical-physiological differences were observed with varying heavy metal soil content, antioxidative enzyme activities increased as a tolerance strategy, and glutathione levels decreased in response to heavy metal toxicity. Heavy metal accumulation also affected the expression of stress-related genes. The highest levels of expression of GST, G6PDH, 6PGD, nitrate reductase 1, and sulfate transporter genes were found in plants collected from site A1. However, auxin-induced protein exhibited its highest expression in plants collected from A2. Six SRAP combinations yielded 25 scoreable markers with a polymorphism rate of 64%, and 5 ISSR markers produced 11 bands with a polymorphism rate of 36.36% for three A. maurorum genotypes. The ME1xEM7 primer combinations provided the most polymorphic information content and resolving power, making it the most useful primer for differentiating A. maurorum genotypes. SRAP markers exhibited a higher diversity index (0.24) than ISSR markers (0.16).
A. maurorum displayed adaptive characteristics for heavy metal sequestration from mining site soils and is proposed as a strong candidate for phytoremediation.
骆驼刺（Alhagi maurorum Medik.）是一种在各种生境中都很常见的沙漠植物，包括埃及西部沙漠。该植物在经济铁矿石矿床及其周围尤其普遍。评估骆驼刺组织和土壤样本中的营养物质和重金属水平，以确定植物和土壤中重金属水平之间的关联。目的是评估该物种作为重金属污染指示物的适用性。评估了光合色素、蛋白质、脯氨酸、生物碱、类黄酮、2,2-二苯基-1-苦基肼自由基清除、还原型谷胱甘肽、丙二醛、抗氧化酶和与应激相关的基因表达，以确定它们在超微和分子结构中适应金属胁迫的功能作用。此外，还使用共显性序列相关扩增多态性（SRAP）和简单序列重复（ISSR）评估了骆驼刺样本的分子遗传变异。
在三个地点采集的样本中，观察到骆驼刺的酶和非酶抗氧化剂存在显著差异。骆驼刺适应了矿区的气候。形态上，茎有刺，叶窄，枝系统简化。解剖学上，叶子和茎上有角质层涂层，陷孔气孔，紧凑的表皮和厚的皮层。随着土壤中重金属含量的变化，观察到显著的解剖生理差异，抗氧化酶活性增加作为一种耐受策略，谷胱甘肽水平随着重金属毒性的增加而降低。重金属积累也影响与应激相关的基因表达。在从 A1 点采集的植物中，GST、G6PDH、6PGD、硝酸还原酶 1 和硫酸盐转运基因的表达水平最高。然而，在从 A2 点采集的植物中，生长素诱导蛋白表现出最高的表达。6 个 SRAP 组合产生了 25 个可评分标记，多态性率为 64%，5 个 ISSR 标记产生了 11 个条带，多态性率为 36.36%，用于三种骆驼刺基因型。ME1xEM7 引物组合提供了最多的多态信息含量和分辨率，是区分骆驼刺基因型的最有用引物。SRAP 标记的多样性指数（0.24）高于 ISSR 标记（0.16）。
骆驼刺表现出从矿区土壤中固定重金属的适应特征，被提议作为植物修复的有力候选物。
