Integrated -omics and functional study of the cell wall folding mechanism in resurrection plants

水资源短缺是对作物产量产生负面影响的最显著的胁迫因素之一，预计未来几十年干旱期的发生将增加。了解抗旱性的机制是至关重要的，以便能够将这些知识转移到旨在提高作物抗旱性的生物技术项目中。细胞壁和质膜在水分流失和随后的膨胀压力损失时受到物理影响，这些结构的破坏导致渗漏并最终导致细胞死亡。在这种情况下，复活植物，即具有显著生存能力的植物，已经被研究来破译它们能够承受极端干燥的机制。目前的项目假设细胞壁蛋白质组及其多糖组成的变化使复活植物（即车前草）能够承受由其相对含水量损失超过95%引起的机械张力（由于胀气损失），并允许在脱水/再水化循环中折叠和展开。随后质膜的脂质组成和蛋白质组的变化允许在氧化应激和组织干燥的情况下保持其完整性。为了验证这一假设，重点将放在细胞壁和质膜的亚细胞特征上：蛋白质组将在水合、脱水和再水合状态下进行分析。为了补充这些数据集，细胞壁的组成将通过成像、免疫学和化学分析来表征，质膜的脂质组成将在相同的生理状态下测定。还将进行功能分析，以验证在细胞壁和质膜上获得的结果，使用前面步骤中描述的烟草和车前草愈伤组织中一些基因的过表达。

Water shortage is one of the most dramatic stress factors negatively impacting crop yield, and the occurrence of drought periods is foreseen to increase in the next decades. It is of the utmost importance to understand the mechanisms involved in drought tolerance to be able to transfer this knowledge in biotechnological programs aimed at improving crop tolerance to drought. Cell walls and plasma membranes are physically affected upon water loss and the subsequently loss of turgor pressure, and breakage of these structures leads to leakages and ultimately cell death. In this context, resurrection plants, i.e. plants with remarkable ability to survive extreme desiccation, have been studied to decipher the mechanisms by which they are able to withstand extreme desiccation. The current project hypothesizes that changes in the cell wall proteome and its polysaccharide composition enable resurrection plants (i.e. Craterostigma plantagineum) to tolerate the mechanical tension (due to turgor loss) caused by a loss of more than 95% of their relative water content and allow folding, unfolding during dehydration/rehydration cycle. Subsequent changes in the lipid composition and the proteome of the plasma membranes are allowing the preservation of its integrity despite oxidative stress and tissue desiccation. In order to test this hypothesis, the focus will be put on subcellular characterization of the cell wall and the plasma membrane: the proteomes will be analysed during hydrated, dehydrated, rehydrated states. To complement these datasets, the composition of the cell wall will be characterized by imaging, immunological and chemical assays and the lipid composition of the plasma membrane will be determined in the same physiological states. A functional analysis will also be performed to validate the results obtained in cell wall and plasma membrane using overexpression of some genes described in previous steps in tobacco and C. plantagineum calli submitted to drought.