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

缺水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。了解干旱耐受性的相关机制，以便能够将这些知识转移到旨在提高作物耐旱性的生物技术计划中，这是至关重要的。细胞壁和质膜在水分损失和随后的膨压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，即具有在极端干旱中生存的显着能力的植物，已经被研究以破译它们能够承受极端干旱的机制。本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Craterostigma plantagineum）能够耐受由超过95%的相对含水量损失引起的机械张力（由于膨压损失），并允许在脱水/复水循环期间折叠，展开。随后的脂质组成和质膜的蛋白质组的变化允许其完整性的保存，尽管氧化应激和组织干燥。为了检验这一假设，重点将放在细胞壁和质膜的亚细胞表征：蛋白质组将在水合，脱水，再水合状态下进行分析。为了补充这些数据集，将通过成像、免疫学和化学测定来表征细胞壁的组成，并且将在相同的生理状态下确定质膜的脂质组成。还将进行功能分析，以验证在烟草和C.车前草愈伤组织经受干旱。

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.