Plasma Membrane-Associated Receptor-like Kinases Relocalize to Plasmodesmata in Response to Osmotic Stress
Plasma Membrane-Associated Receptor-like Kinases Relocalize to Plasmodesmata in Response to Osmotic Stress
复制标题
DOI：
10.1104/pp.19.00473
复制
发表时间：
2019-09-01
期刊：
影响因子：
7.4
通讯作者：
Bayer, Emmanuelle M.
中科院分区：
文献类型：
--
作者：
Grison, Magali S.;Kirk, Philip;Bayer, Emmanuelle M.
胞间连丝是细胞间通讯的重要组成部分，协调植物生长、发育和对环境胁迫的反应。虽然许多发育、生物和非生物信号主要通过受体蛋白在质膜（PM）上感知，但胞间连丝也聚集受体样活性;这两种途径是否相互作用目前尚不清楚。在这里，我们表明，特定的PM-位于亮氨酸丰富的重复受体样激酶，钱寿激酶（QSK 1）和花序分生组织激酶2，在最佳生长条件下是不存在的胞间连丝，迅速搬迁和集群的孔响应渗透胁迫。这一过程非常快，不是PM相关蛋白的一般特征，并且不依赖于固醇和鞘脂膜组成。专注于QSK 1，以前报道参与应激反应，我们表明，响应甘露醇的重新定位依赖于QSK 1磷酸化。QSK 1功能缺失突变导致侧根发育延迟，并影响根对甘露醇胁迫的反应。胼胝体介导的胞间连丝调节已知调节LR发育。我们发现，胼胝质水平降低qsk 1突变体的背景下，根表型类似异位表达的PdBG 1，一种酶，降解胼胝质在孔。LR和胼胝质表型都可以通过表达野生型和拟磷酸化的QSK 1变体来补充，但不能通过磷酸化死亡的QSK 1突变体来补充，该突变体不能在胞间连丝处重新定位。总之，这些数据表明，重组的受体样激酶的胞间连丝是重要的胼胝质和LR发展的调节作为植物对渗透胁迫的反应的一部分。
Plasmodesmata act as key elements in intercellular communication, coordinating processes related to plant growth, development, and responses to environmental stresses. While many of the developmental, biotic, and abiotic signals are primarily perceived at the plasma membrane (PM) by receptor proteins, plasmodesmata also cluster receptor-like activities; whether these two pathways interact is currently unknown. Here, we show that specific PM-located Leu-rich-repeat receptor-like-kinases, Qian Shou kinase (QSK1) and inflorescence meristem kinase2, which under optimal growth conditions are absent from plasmodesmata, rapidly relocate and cluster to the pores in response to osmotic stress. This process is remarkably fast, is not a general feature of PM-associated proteins, and is independent of sterol and sphingolipid membrane composition. Focusing on QSK1, previously reported to be involved in stress responses, we show that relocalization in response to mannitol depends on QSK1 phosphorylation. Loss-of-function mutation in QSK1 results in delayed lateral root (LR) development, and the mutant is affected in the root response to mannitol stress. Callose-mediated plasmodesmata regulation is known to regulate LR development. We found that callose levels are reduced in the qsk1 mutant background with a root phenotype resembling ectopic expression of PdBG1, an enzyme that degrades callose at the pores. Both the LR and callose phenotypes can be complemented by expression of wild-type and phosphomimic QSK1 variants, but not by phosphodead QSK1 mutant, which fails to relocalize at plasmodesmata. Together, the data indicate that reorganization of receptor-like-kinases to plasmodesmata is important for the regulation of callose and LR development as part of the plant response to osmotic stress.