Expression data from leaves of rice plants overexpressing the OsCPK4 gene and control plants(empty vector) in normal conditions

The OsCPK4 gene is a member of the complex gene family of the Calcium-dependent protein kinases (CPKs) in rice. Expression of OsCPK4 is induced by high salinity, drought and the phytohormone abscisic acid. The OsCPK4 protein localizes to the plasma membrane. Transgenic rice overexpressing OsCPK4 enhances tolerance to salt and drought stress, the transgenic plants having stronger water-holding capability than control plants. Microarray analysis of OsCPK4 rice plants revealed up-regulation of genes involved in metabolism, particularly lipid metabolism, as well as genes involved in oxidative stress and redox control. Meanwhile, OsCPK4 overexpression has no impact on the expression of the well-characterized abiotic stress-associated transcription factors (i.e. DREB and NAC), or the typical salt and drought-inducible genes (i.e. LEA genes, including Dehydrin genes). Under salt stress conditions, the OsCPK4 transgenic lines showed lesser membrane lipid peroxidation as compared to control plants, indicating that OsCPK4 rice plants have a better capacity to prevent oxidative damage in cellular membrane lipids. Collectively, our data suggest that OsCPK4-mediated processes protect the plant cell from uncontrolled redox reactions affecting membrane functions, which, in turn, results in salt and drought tolerance. OsCPK4 shows great promise for genetic improvement of tolerance to abiotic stress in rice. Leaves of OsCPK4 and vector control plants that had been grown hydroponically for 15 days were harvested and used for total RNA extraction and hybrizations in two color customized Agilent microarrays.

OsCPK4基因是水稻钙依赖性蛋白激酶（Calcium-dependent protein kinases, CPKs）复杂基因家族的成员之一。OsCPK4的表达可被高盐、干旱以及植物激素脱落酸（abscisic acid）诱导。OsCPK4蛋白定位于质膜。过表达OsCPK4的转基因水稻可提升其对盐胁迫与干旱胁迫的耐受性，转基因植株的持水能力优于对照植株。对转OsCPK4水稻植株的微阵列分析结果显示，参与代谢过程（尤其是脂质代谢）的基因以及参与氧化应激与氧化还原调控的基因均出现表达上调。与此同时，OsCPK4过表达不会对已被充分研究的非生物胁迫相关转录因子（如DREB、NAC），或是典型的盐、干旱诱导基因（如包含脱水素基因（Dehydrin genes）在内的LEA基因）的表达产生影响。在盐胁迫条件下，转OsCPK4水稻株系的膜脂过氧化程度低于对照植株，这表明转OsCPK4水稻拥有更强的能力以防止细胞膜脂发生氧化损伤。综上，本研究数据表明，OsCPK4介导的生物学过程可保护植物细胞免受影响膜功能的失控氧化还原反应的侵害，进而赋予植株盐、干旱胁迫耐受性。OsCPK4在水稻非生物胁迫耐受性的遗传改良领域展现出巨大应用前景。将水培15天的转OsCPK4水稻植株与空载体对照植株的叶片采集后，用于总RNA提取以及双色定制安捷伦（Agilent）微阵列杂交实验。