The role of WHIRLY1 in chloroplast-based perception of stress and in chloroplast-to-nucleus signaling

WHIRLY1 在基于叶绿体的应激感知和叶绿体到细胞核信号传导中的作用

• 批准号: 279515066
• 负责人: Professorin Dr. Karin Krupinska
• 金额: --
• 依托单位: Botanisches Institut und Botanischer Garten
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/279515066?language=en
• 关键词: role; WHIRLY1; chloroplast; based; perception

Plant development and productivity require an efficient adaptation of the photosynthetic apparatus to the environment and are limited by stress factors. Stress-induced disturbances in the photosynthetic apparatus are sensed in chloroplasts and are transmitted to the nucleus to adjust gene expression leading to an acclimation of the plants. Among the well-studied signals produced during stress in chloroplasts are reactive oxygen species (ROS) and redox changes in the photosynthetic electron chain. So far, the mechanisms of signal transference from chloroplasts to the nucleus are not well understood.In this project it will be investigated whether the RNA/DNA binding protein WHIRLY1, being dually located in chloroplasts and the nucIeus of the same cell is involved in chloroplast-based perception of stress and in stress-induced chloroplast-to-nucleus signaling. Preliminary studies showed that WHIRLY1 is located in chloroplast nucleoids as well as at the thylakoid membranes, making it an ideal candidate adaptor perceiving signals from photosynthesis and adjusting plastid gene expression. Accordingly, during high light stress chloroplast development is disturbed in transgenic barley plants with reduced amount of WHIRLY1. WHIRLY1 can form oligomers or can be present as a monomer. The monomeric form might be formed in response to redox changes in chloroplasts of stress exposed plants. The ratio of oligomers to monomers will be analysed biochemically with barley plants exposed to different stress conditions. Additional investigations will be done with isolated chloroplasts, in which the redox state and/or the production of ROS will be altered by application of inhibitors of photosynthesis. Transgenic barley lines with altered amounts of WHIRLY1 will be used to investigate the impact of WHIRLY1 on acclimation towards various stress conditions, i.e. drought and high irradiance in combination with cold. Measurements of photosynthesis and nuclear gene expression are envisaged. The distribution of WHIRLY1 between chloroplasts and nucleus will be immunologically analysed in barley. For investigations on the mechanisms of putative stress-induced changes in the subcellular distribution of WHIRLY1, transgenic Arabidopsis plants overexpressing mutated sequences of WHIRLY1 are available. Besides the lysine residue K91 responsible for oligomerization of the protein the conserved cysteine residue C159 possibly involved in redox dependent changes of the WHIRLY1 conformation has been replaced by alanine. Additionally, transplastomic tobacco plants expressing the mutated sequences inside the plastids have been prepared. Visualization of the subcellular distribution of WHIRLY1 will be done with Arabidopsis plants accumulating fluorescing fusion proteins (WHIRLY1:iLOV).

植物的发育和生产力需要光合机构有效地适应环境，并受到胁迫因素的限制。胁迫诱导的光合机构中的干扰在叶绿体中被感知，并被传递到细胞核以调节基因表达，从而导致植物的驯化。在叶绿体胁迫过程中产生的信号中，有活性氧（ROS）和光合电子链中的氧化还原变化。目前，叶绿体向细胞核的信号传递机制尚不清楚，本研究将探讨同时存在于叶绿体和细胞核中的RNA/DNA结合蛋白WHIRLY 1是否参与叶绿体对胁迫的感知以及胁迫诱导的叶绿体向细胞核的信号传递。初步研究表明，WHIRLY 1基因定位于叶绿体类核和类囊体膜上，是一个理想的候选衔接子，可以感知光合作用信号，调节质体基因表达。因此，在强光胁迫期间，在具有减少量的WHIRLY 1的转基因大麦植物中叶绿体发育受到干扰。WHIRLY 1可形成低聚物或可作为单体存在。单体形式可能是响应于胁迫暴露植物叶绿体中的氧化还原变化而形成的。低聚物与单体的比率将用暴露于不同胁迫条件的大麦植物进行生化分析。另外的研究将与分离的叶绿体，其中的氧化还原状态和/或ROS的生产将被改变的光合作用的抑制剂的应用。具有改变量的WHIRLY 1的转基因大麦系将用于研究WHIRLY 1对各种胁迫条件（即干旱和高辐照与寒冷的组合）的驯化的影响。设想对光合作用和核基因表达进行测量。将对大麦中的WHIRLY 1在叶绿体和细胞核之间的分布进行免疫学分析。为了研究假定的胁迫诱导的WHIRLY 1亚细胞分布变化的机制，可获得过表达WHIRLY 1突变序列的转基因拟南芥植物。除了负责蛋白质寡聚化的赖氨酸残基K91外，可能参与WHIRLY 1构象氧化还原依赖性变化的保守半胱氨酸残基C159已被丙氨酸取代。此外，已经制备了在质体内表达突变序列的转质体烟草植物。将用积累荧光融合蛋白（WHIRLY 1：iLOV）的拟南芥植物进行WHIRLY 1的亚细胞分布的可视化。