State Key Laboratory of Cotton Biology; Henan Key Laboratory of Plant Stress Biology; School of Life Science, Henan University, Kaifeng, Henan, 475004, People's Republic of China.
State Key Laboratory of Cotton Biology, Institute of Cotton Research of CAAS, Anyang, 455000, People's Republic of China.
BMC Plant Biol. 2018 Jan 17;18(1):15. doi: 10.1186/s12870-018-1230-8.
Soil salinization is one of the major environmental constraints to plant growth and agricultural production worldwide. Signaling components involving calcium (Ca) and the downstream calcium-dependent protein kinases (CPKs) play key roles in the perception and transduction of stress signals. However, the study of CPKs in cotton and their functions in response to salt stress remain unexplored.
A total of 98 predicted CPKs were identified from upland cotton (Gossypium hirsutum L. 'TM-1'), and phylogenetic analyses classified them into four groups. Gene family distribution studies have revealed the substantial impacts of the genome duplication events to the total number of GhCPKs. Transcriptome analyses showed a wide distribution of CPKs' expression among different organs. A total of 19 CPKs were selected for their rapid responses to salt stress at the transcriptional level, most of which were also incduced by the thylene-releasing chemical ethephon, suggesting a partal overlap of the salinity and ethylene responses. Silencing of 4 of the 19 CPKs (GhCPK8, GhCPK38, GhCPK54, and GhCPK55) severely compromised the basal cotton resistance to salt stress.
Our genome-wide expression analysis of CPK genes from up-land cotton suggests that CPKs are involved in multiple developmental responses as well as the response to different abiotic stresses. A cluster of the cotton CPKs was shown to participate in the early signaling events in cotton responses to salt stress. Our results provide significant insights on functional analysis of CPKs in cotton, especially in the context of cotton adaptions to salt stress.
土壤盐渍化是全球范围内植物生长和农业生产的主要环境限制因素之一。涉及钙（Ca）和下游钙依赖蛋白激酶（CPKs）的信号成分在胁迫信号的感知和转导中发挥着关键作用。然而，棉花中 CPK 的研究及其对盐胁迫的反应功能仍未被探索。
从陆地棉（Gossypium hirsutum L. 'TM-1'）中鉴定出了 98 个预测的 CPK，系统发育分析将它们分为四个组。基因家族分布研究表明，基因组复制事件对 GhCPKs 的总数产生了重大影响。转录组分析显示 CPK 在不同器官中的表达广泛分布。共有 19 个 CPK 因在转录水平上对盐胁迫的快速反应而被选中，其中大多数也被乙烯释放化学物质乙烯利诱导，表明盐度和乙烯反应存在部分重叠。19 个 CPK 中的 4 个（GhCPK8、GhCPK38、GhCPK54 和 GhCPK55）的沉默严重削弱了棉花对盐胁迫的基础抗性。
我们对陆地棉 CPK 基因的全基因组表达分析表明，CPKs 参与了多种发育反应以及对不同非生物胁迫的反应。棉花 CPK 的一个簇被证明参与了棉花对盐胁迫反应的早期信号事件。我们的研究结果为棉花 CPK 的功能分析提供了重要的见解，特别是在棉花适应盐胁迫的背景下。
