Nguyen Hung Manh, Kim Mikael, Ralph Peter J, Marín-Guirao Lázaro, Pernice Mathieu, Procaccini Gabriele
Stazione Zoologica Anton Dohrn, Villa Comunale, Naples, Italy.
Seagrass Ecology Group, Oceanographic Center of Murcia, Spanish Institute of Oceanography, Murcia, Spain.
Front Plant Sci. 2020 Apr 28;11:494. doi: 10.3389/fpls.2020.00494. eCollection 2020.
While thermal priming and the relative role of epigenetic modifications have been widely studied in terrestrial plants, their roles remain unexplored in seagrasses so far. Here, we experimentally compared the ability of two different functional types of seagrass species, dominant in the Southern hemisphere, climax species and pioneer species , to acquire thermal-stress memory to better survive successive stressful thermal events. To this end, a two-heatwave experimental design was conducted in a mesocosm setup. Findings across levels of biological organization including the molecular (gene expression), physiological (photosynthetic performances and pigments content) and organismal (growth) levels provided the first evidence of thermal priming in seagrasses. Non-preheated plants suffered a significant reduction in photosynthetic capacity, leaf growth and chlorophyll content, while preheated plants were able to cope better with the recurrent stressful event. Gene expression results demonstrated significant regulation of methylation-related genes in response to thermal stress, suggesting that epigenetic modifications could play a central role in seagrass thermal stress memory. In addition, we revealed some interspecific differences in thermal responses between the two different functional types of seagrass species. These results provide the first insights into thermal priming and relative epigenetic modifications in seagrasses paving the way for more comprehensive forecasting and management of thermal stress in these marine foundation species in an era of rapid environmental change.
虽然热启动以及表观遗传修饰的相对作用已在陆生植物中得到广泛研究，但迄今为止它们在海草中的作用仍未得到探索。在此，我们通过实验比较了南半球占主导地位的两种不同功能类型的海草物种，即顶极物种和先锋物种，获得热应激记忆以更好地在连续的应激热事件中生存的能力。为此，在一个中型生态系统设置中进行了双热浪实验设计。在包括分子（基因表达）、生理（光合性能和色素含量）和个体（生长）水平在内的生物组织层面上的研究结果，首次证明了海草中存在热启动现象。未预热的植物光合能力、叶片生长和叶绿素含量显著降低，而预热的植物能够更好地应对反复出现的应激事件。基因表达结果表明，甲基化相关基因在热应激反应中受到显著调控，这表明表观遗传修饰可能在海草热应激记忆中起核心作用。此外，我们还揭示了两种不同功能类型的海草物种在热反应方面存在一些种间差异。这些结果首次深入了解了海草中的热启动和相关表观遗传修饰，为在快速环境变化时代对这些海洋基础物种的热应激进行更全面的预测和管理铺平了道路。
