Moringa oleifera is a fast-growing hygrophilic tree native to a humid sub-tropical region of India, now widely planted in many regions of the Southern Hemisphere characterized by low soil water availability. The widespread cultivation of this plant worldwide may have led to populations with different physiological and biochemical traits. In this work, the impact of water stress on the physiology and biochemistry of two M. oleifera populations, one from Chaco Paraguayo (PY) and one from Indian Andhra Pradesh (IA) region, was studied in a screenhouse experiment where the water stress treatment was followed by re-watering. Through transcriptome sequencing, 2201 potential genic simple sequence repeats were identified and used to confirm the genetic differentiation of the two populations. Both populations of M. oleifera reduced photosynthesis, water potential, relative water content and growth under drought, compared to control well-watered plants. A complete recovery of photosynthesis after re-watering was observed in both populations, but growth parameters recovered better in PY than in IA plants. During water stress, PY plants accumulated more secondary metabolites, especially β-carotene and phenylpropanoids, than IA plants, but IA plants invested more into xanthophylls and showed a higher de-epoxidation state of xanthophylls cycle that contributed to protect the photosynthetic apparatus. M. oleifera demonstrated a high genetic variability and phenotypic plasticity, which are key factors for adaptation to dry environments. A higher plasticity (e.g. in PY plants adapted to wet environments) will be a useful trait to endure recurrent but brief water stress episodes, whereas long-term investment of resources into secondary metabolism (e.g. in IA plants adapted to drier environments) will be a successful strategy to cope with prolonged periods of drought. This makes M. oleifera an important resource for agro-forestry in a climate change scenario.

中文翻译：

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水分胁迫和复水条件下来自不同气候区的两种油橄榄分枝杆菌的表型可塑性。

辣木是一种生长迅速的吸水树，原产于印度的亚热带湿润地区，目前在南半球的许多地区普遍种植，其土壤水利用率低。该植物在世界范围内的广泛种植可能导致了具有不同生理和生化特性的种群。在这项工作中，在筛选试验中研究了水分胁迫对两个油茶分枝杆菌种群的生理和生化的影响，一个来自Chaco Paraguayo（PY），另一个来自印度安得拉邦（IA）地区。然后再浇水。通过转录组测序，鉴定了2201个潜在的基因简单序列重复序列，并用于确认这两个种群的遗传分化。油橄榄分枝杆菌的两个种群都降低了光合作用，与对照灌溉良好的植物相比，水势，相对水分含量和干旱条件下的生长。在两个种群中都观察到再浇水后光合作用的完全恢复，但是PY的生长参数恢复得比IA植物更好。在水分胁迫期间，PY植物比IA植物积累了更多的次生代谢产物，尤其是β-胡萝卜素和苯基丙烷，但是IA植物对叶黄素的投入更多，并且显示出较高的叶黄素循环脱环状态，这有助于保护光合作用。油橄榄表现出很高的遗传变异性和表型可塑性，这是适应干旱环境的关键因素。较高的可塑性（例如在适应潮湿环境的PY植物中）将是忍受反复出现但短暂的水分胁迫发作的有用特性，而对次级代谢的长期资源投资（例如在适应干旱环境的IA植物中）将是应对长期干旱的成功策略。在气候变化的情况下，这使得油松分枝杆菌成为农林业的重要资源。