Studies of vacuolar transporters controlling nutrient storage and ion detoxification in Arabidopsis thaliana

拟南芥液泡转运蛋白控制养分储存和离子解毒的研究

• 批准号: 316850664
• 负责人: Dr. Melanie Krebs
• 金额: --
• 依托单位: Forschungsgruppe Zellbiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/316850664?language=en
• 关键词: Studies; vacuolar; transporters; controlling; nutrient

The vacuole and TGN/EE (trans-Golgi network/early endosome) are intracellular compartments essential for nutrient accumulation and cytosolic ion detoxification by compartmentalizing the different cellular components. The multiple roles of these compartments are tightly linked to the activities of transporters present in their membranes. It is assumed that transporters use the energy of the electrochemical gradient generated by proton pumps such as the V-type H+-Adenosintriphosphatases (V-ATPase). The studies on V-ATPase suggest a specificity of action: a vha-a2 vha-a3 knock-out Arabidopsis mutant affected in vacuolar V-ATPase activity specifically reduces the vacuolar storage of nitrate but not the sequestration of chloride whereas the sensitivity to NaCl salt stress increases in a knock-down mutant of vha-a1, a mutant with reduced V-ATPase activity at the TGN/EE. The project aims at understanding the molecular basis of this functional specification through the analysis of interaction between V-ATPase and CLC anion transporters in Arabidopsis. This latter protein family is characterized by interesting features: (1) they can be channel (passive transporter) or anion/proton exchangers (active transporter) although all the members are structurally very close, (2) they can be either more selective for chloride or nitrate depending of a presence of a serine/proline in their selectivity filter and, (3) members are present on both TGN/EE and vacuolar membranes. The project will be divided in three Tasks: Task 1 will investigate the specificities/redundancies of AtCLCs localised in the vacuole and the TGN/EE. The two other Tasks will analyze the co-regulation between V-ATPase and AtCLCs in the vacuolar (Task 2) and TGN/EE membrane (Task 3). The project will take advantage of the expertise of two expert groups in the field of primary and secondary transport in Arabidopsis thaliana. The French partner will provide knowledge in molecular physiology and electrophysiology which will be complemented by cell biological and omics approaches of the German partner. The cooperation between the two laboratories will allow an in-depth analyses of the interaction between V-ATPase and AtCLC at the molecular, cellular and whole-plant level, taking different environmental fluctuations (nitrate concentrations, drought and NaCl stress) into account. Overall, this project will gain new insights into the coordination of primary and secondary transport processes at the tonoplast and TGN/EE and holds the potential for developing future strategies to improve crops for nutrient assimilation and tolerance to abiotic stress.

液泡和 TGN/EE（跨高尔基体网络/早期内体）是细胞内区室，通过划分不同的细胞成分，对于营养物积累和胞质离子解毒至关重要。这些区室的多重作用与其膜中转运蛋白的活动紧密相关。假设转运蛋白利用质子泵（例如 V 型 H+-腺苷三磷酸酶 (V-ATPase)）产生的电化学梯度的能量。对 V-ATP 酶的研究表明其作用的特异性：受液泡 V-ATP 酶活性影响的 vha-a2 vha-a3 敲除拟南芥突变体特异性地减少了硝酸盐的液泡储存，但不减少氯离子的封存，而 vha-a1 的敲低突变体（一种在 V-ATP 酶活性降低的突变体）中对 NaCl 盐胁迫的敏感性增加。 TGN/EE。该项目旨在通过分析拟南芥中 V-ATP 酶和 CLC 阴离子转运蛋白之间的相互作用，了解这种功能规范的分子基础。后一个蛋白质家族具有有趣的特征：（1）它们可以是通道（被动转运蛋白）或阴离子/质子交换器（主动转运蛋白），尽管所有成员在结构上都非常接近，（2）它们可以对氯化物或硝酸盐更具选择性，具体取决于其选择性过滤器中丝氨酸/脯氨酸的存在，（3）成员同时存在于 TGN/EE 和液泡膜上。该项目将分为三个任务：任务 1 将研究位于液泡和 TGN/EE 中的 AtCLC 的特异性/冗余。另外两项任务将分析液泡（任务 2）和 TGN/EE 膜（任务 3）中 V-ATPase 和 AtCLC 之间的共同调节。该项目将利用拟南芥初级和次级运输领域两个专家组的专业知识。法国合作伙伴将提供分子生理学和电生理学方面的知识，德国合作伙伴的细胞生物学和组学方法将对此进行补充。两个实验室之间的合作将允许在分子、细胞和全植物水平上深入分析V-ATP酶和AtCLC之间的相互作用，并考虑到不同的环境波动（硝酸盐浓度、干旱和氯化钠胁迫）。总体而言，该项目将对液泡膜和 TGN/EE 的初级和次级运输过程的协调获得新的见解，并具有制定未来策略以改善作物养分同化和对非生物胁迫耐受性的潜力。