Novel players of the cell wall integrity sensing pathway controlled by the ANXUR Receptor-like kinases.

植物细胞指导细胞外基质的合成/沉积，该细胞外基质刚性但动态地被称为细胞壁（CW），其在发育期间实现各种关键功能。细胞在生长过程中合成初级CW，这取决于预先存在的CW的松动/变形和新物质的持续分泌之间的平衡。这种必要的协调要求细胞被告知影响其CW特性的任何环境扰动，以避免生长停滞或破裂。为了避免这些灾难性的情况下，它已经变得越来越明显，植物细胞已经开发了CW完整性（CWI）的传感机制，以中继有关CW性能的信息到内部的生长机制。尽管其在植物发育和生长中的重要性，但是我们对CW和细胞内机制之间的信号传导机制的理解仍然贫乏。长春花受体样激酶（RLKs）类RLK 1（CrRLK 1 L）家族最近已经成为在发育期间协调细胞生长、细胞-细胞通讯和CW重塑的候选者（Lindner，et al.，2012年）。有趣的是，两个冗余的CrRLK 1 L成员命名为ANXUR 1（ANX 1）和ANX 2的功能在控制CW完整性（CWI）的花粉管（PT），开花植物的雄配子体。在两种受体中携带突变的花粉在萌发后不久破裂，阻止它们形成雌配子体，从而导致不育（Boisson-Dernier等人，2009年）。最近，ANX-RLK显示通过NADPH氧化酶调节H2 O2产生、Ca 2+稳态和分泌，以实现稳定生长而不丧失完整性（Boisson-Dernier，et al.，为了鉴定这一基本上未探索的途径的新参与者，进行了anxl; anx 2不育抑制子筛选，并导致鉴定了由于拯救anxl; anx 2 PT生长而具有改善的生育力的抑制子。对于我们的前两个抑制子，通过下一代测序确定了新的受体样胞质激酶（RLCK）和蛋白质Ser/Thr磷酸酶（PPP）的关键功能域中的非同义突变。RLCK和PPP都是花粉优先表达的，并根据伊特鲁里亚人的生育和再生神分别命名为MARIS（MRI）和ATUNIS 1（AUN 1）。通过一个跨学科的建议，包括最先进的技术，在分子和细胞生物学，遗传学和生物化学，我们建议解开MRI和AUN 1的作用，在ANX-RLK依赖CWI传感途径。

Plant cells are directing the synthesis/deposition of an extracellular matrix rigid yet dynamic known as the cell wall (CW) that fulfils various key functions during development. The cells synthesize primary CWs during growth, which depends on the balance between loosening/deformation of the pre-existing CW and continuous secretion of new material. This essential coordination requires the cell to be informed of any environmental perturbations that impact its CW properties so as to avoid growth arrest or rupture. To circumvent these catastrophic scenarios, it has become increasingly evident that plant cells have developed CW integrity (CWI) sensing mechanisms to relay information about CW performance to the internal growth machinery. Despite its importance in plant development and growth, our understanding of the signalling mechanisms between the CW and the intracellular machineries remains however meagre.The receptor-like kinases (RLKs) of the Catharanthus roseus RLK1-like (CrRLK1L) family have recently emerged as candidates for coordinating cell growth, cell-cell communication, and CW remodelling during development (Lindner, et al., 2012). Interestingly, two redundant CrRLK1L members named ANXUR1 (ANX1) and ANX2 function in the control of CW integrity (CWI) in pollen tubes (PTs), the male gametophyte of flowering plants. Pollen carrying mutations in both receptors burst shortly after germination, preventing them from fertilizing female gametophytes thereby leading to sterility (Boisson-Dernier, et al., 2009). Recently, ANX-RLKs were shown to regulate H2O2 production, Ca2+ homeostasis and secretion through NADPH oxidases to achieve steady growth without losing integrity (Boisson-Dernier, et al., 2013).To identify new players of this largely unexplored pathway, a anx1;anx2 sterility suppressor screen was performed and led to the identification of suppressors with improved fertility due to rescue of anx1;anx2 PT growth. For our first two suppressors, mapping by next-generation sequencing identified non-synonymous mutations in key functional domains of a novel receptor-like cytoplasmic kinase (RLCK) and a protein Ser/Thr phosphatase (PPP), respectively. Both the RLCK and the PPP are pollen-preferentially expressed and were named MARIS (MRI) and ATUNIS1 (AUN1) according to Etruscan deities of fertility and rebirth, respectively. Through an interdisciplinary proposal that includes state-of-the-art techniques in molecular and cell biology, genetics and biochemistry we propose to unravel the role of MRI and AUN1 in the ANX-RLK dependent CWI sensing pathway.