1. Interaction between calcium and potassium modulates elongation rate in cotton fiber cells
- Author
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Kai Guo, Maojun Wang, Lili Tu, Xianlong Zhang, Zhonghua Li, Hui Huang, Jinwu Deng, and Yonghui He
- Subjects
0106 biological sciences ,0301 basic medicine ,Physiology ,fiber elongation ,chemistry.chemical_element ,Cyclopentanes ,Plant Science ,Calcium ,01 natural sciences ,Mass Spectrometry ,Cell wall ,Abscisic acid ,03 medical and health sciences ,Expansin ,chemistry.chemical_compound ,Plant Growth Regulators ,Cell Wall ,Gene Expression Regulation, Plant ,Cotton Fiber ,Oxylipins ,Fiber ,ionome ,Plant Proteins ,Ovule ,Gossypium ,calcium ,Sequence Analysis, RNA ,potassium ,Spectrophotometry, Atomic ,Phytosulfokine ,jasmonic acid ,ROS ,Biological Transport ,Research Papers ,030104 developmental biology ,chemistry ,Fiber cell ,Biophysics ,Growth and Development ,Elongation ,Reactive Oxygen Species ,Protein Kinases ,010606 plant biology & botany - Abstract
Potassium maintains cotton fiber cell elongation under conditions of calcium deficiency, through the CBL-INTERACTING PROTEIN KINASE 6 (GhCIPK6) gene., Calcium (Ca2+) is necessary for fiber cell development in cotton (Gossypium hirsutum), both as a cell wall structural component and for environmental signaling responses. It is also known that potassium (K+) plays a critical role in cotton fiber cell elongation. However, it is unclear whether Ca2+ integrates its activities with K+ to regulate fiber elongation. Here, we report the novel discovery that Ca2+ deficiency, when integrated with K+ signaling, promotes fiber elongation. Using inductively coupled plasma–mass spectrometry (ICP-MS), we determined dynamic profiles of the ionome in ovules and fibers at different developmental stages, and found that a high accumulation of macro-elements, but not Ca2+, was associated with longer fibers. Using an in vitro ovule culture system, we found that under Ca2+-deficient conditions, sufficient K+ (52 mM) rapidly induced ovule and fiber browning, while reduced K+ (2 or 27 mM) not only suppressed tissue browning but also altered fiber elongation. Reduced K+ also enhanced reactive oxygen species scavenging ability and maintained abscisic acid and jasmonic acid levels, which in turn compensated for Ca2+ deficiency. Ca2+ deficiency combined with reduced K+ (0 mM Ca2+ and 27 mM K+) produced longer fibers in cultured ovules, due to cell wall loosening by phytosulfokine (PSK), expansin (EXP), and xyloglucan endotransglycosylase/hydrolase (XTH), and an increase of the K+ content of fiber cells. Using transgenic cotton, we showed that the CBL-INTERACTING PROTEIN KINASE 6 (GhCIPK6) gene mediates the uptake of K+ under Ca2+-deficient conditions. This study establishes a new link between Ca2+, K+, and fiber elongation.
- Published
- 2017