ABSTRACT

Nitrate signaling integrates and coordinates the expression of a wide range of genes, metabolic pathways and ultimately, plant growth and development. Calcium signaling is proved to be involved in the primary nitrate response pathway. However, it is much less understood how calcium signaling mediates nitrate sensing and responses from the extracellular space to cytoplasm, then to the nucleus. In this review, we describe how transceptor-channel complex (cyclic nucleotide-gated channel protein 15 interacting with nitrate transceptor, CNGC15-NRT1.1), calcineurin B-like proteins (CBLs, CBL1, CBL9), CBL-interacting protein kinases (CIPKs), phospholipase C (PLC) and calcium-dependent protein kinases (CDPKs, also CPKs), acting as key players, complete a potential backbone of the nitrate-signaling pathway, from the plasma membrane to the nucleus. NRT1.1 together with CBL1/9-CIPK23 and CBL-CIPK8 links the NO₃⁻ signaling to cytoplasmic and nuclear regulators and triggers downstream NO₃⁻ responses. PLCs and inositol 1, 4, 5-triphosphate (IP3) connect NO₃⁻ signaling and cytoplasmic Ca²⁺ signature. CPK10/30/32 fill the gap between NRT1.1 and NIN-like protein (NLP) transcription factors. The arabidopsis nitrate regulated1 (ANR1) is induced from the endosome by the Ca²⁺–CPKs–NLPs signaling pathway activated by the unphosphorylated form of NRT1.1 (NRT1.1 ^T101A) at high nitrate condition. Understanding how calcium signaling interconnects the upstream nitrate sensor complex with downstream multiple sensors of the nitrate-signaling pathway is key to completing the nutrient–growth regulatory networks.

摘要

硝酸盐信号整合和协调多种基因、代谢途径的表达，并最终促进植物的生长和发育。钙信号被证明参与了主要的硝酸盐反应途径。然而，人们对钙信号如何介导硝酸盐感应以及从细胞外空间到细胞质，然后到细胞核的反应知之甚少。在这篇综述中，我们描述了受体通道复合物（环核苷酸门控通道蛋白 15 与硝酸盐受体相互作用，CNGC15-NRT1.1）、钙调神经磷酸酶 B 样蛋白（CBLs、CBL1、CBL9）、CBL 相互作用蛋白激酶（ CIPKs)、磷脂酶 C (PLC) 和钙依赖性蛋白激酶 (CDPKs，也称为 CPKs) 作为关键参与者，完成了从质膜到细胞核的硝酸盐信号通路的潜在骨架。NRT1。₃ ^-向细胞质和核调节剂发出信号并触发下游 NO ₃ ^-反应。PLC 和肌醇 1、4、5-三磷酸 (IP3) 连接 NO ₃ ^-信号传导和细胞质 Ca ²⁺特征。CPK10/30/32 填补了 NRT1.1 和 NIN 样蛋白 (NLP) 转录因子之间的空白。拟南芥硝酸盐调节 1 (ANR1) 由内体诱导的 Ca ²⁺ -CPKs-NLPs 信号通路由 NRT1.1 的非磷酸化形式 (NRT1.1 ^{T101A ) 激活}) 在高硝酸盐条件下。了解钙信号如何将上游硝酸盐传感器复合物与硝酸盐信号通路的下游多个传感器互连是完成营养生长调节网络的关键。