植物学报 ›› 2015, Vol. 50 ›› Issue (2): 206-216.DOI: 10.3724/SP.J.1259.2015.00206

• 研究报告 • 上一篇    下一篇

外源Ca2+对PEG处理下转C4PEPC基因水稻光合生理的调节

刘小龙1, 2, 李霞2, *, 钱宝云1, 2   

  1. 1南京农业大学生命科学学院, 南京 210095;
    2.江苏省农业科学院粮食作物研究所, 国家水稻改良中心南京分中心, 江苏省优质水稻工程技术研究中心, 南京 210014
  • 收稿日期:2014-02-19 修回日期:2014-05-13 出版日期:2015-03-01 发布日期:2015-04-10
  • 通讯作者: jspplx@jaas.ac.cn
  • 基金资助:
    国家自然科学基金(No.31371554)、江苏省自主创新基金(No.CX[(14)5004])和江苏省自然科学基金(No.BK20130708)

Photosynthetic and Physiological Regulation of C4 Phosphoenol- pyruvate Carboxylase Transgenic Rice (Oryza sativa) by Exogenous Ca2+ Under Polyethylene Glycol Stress

Xiaolong Liu1, 2, Xia Li2, *, Baoyun Qian1, 2   

  1. 1College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China;
    2.Jiangsu High Quality Rice R&D Center, Nanjing Branch of China National Center Rice Improvement, Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
  • Received:2014-02-19 Revised:2014-05-13 Online:2015-03-01 Published:2015-04-10

摘要: 磷酸烯醇式丙酮酸羧化酶(PEPC)通过固定二氧化碳参与光合作用, 是关键的C4植物光合作用酶。为了揭示高光效转C4 PEPC基因水稻(Oryza sativa)对干旱胁迫的适应机理, 以高表达转C4 PEPC水稻(PC)和野生型水稻Kitaake (WT)为供试材料, 在植株的4-5叶期, 使用不同浓度外源CaCl2溶液处理, 测定在15%聚乙二醇6000 (polyethylene glycol-6000, PEG-6000)胁迫下叶片相对含水量、光合参数、内源钙总含量、叶片总蛋白激酶活性、PEPC酶活性以及相关基因表达和蛋白质含量。结果表明, 0.5 mmol∙L-1 CaCl2明显提高PC叶片相对含水量(P<0.05), 2 mmol∙L-1和10 mmol∙L-1 CaCl2则作用不显著, 对WT则影响不显著。不同浓度钙处理对PEG处理PC的净光合速率影响不显著, 而通过维持气孔导度减少水分胁迫。内源总钙浓度的数据显示, 在PEG6000处理下, PC具有维持稳定内源Ca2+浓度的能力, 过高浓度(10 mmol∙L-1 CaCl2)钙处理反而降低了PEPC酶活性、PEPC基因表达和可溶性蛋白的含量。

Abstract: Phosphoenolpyruvate carboxylase (PEPC), a key C4 photosynthetic enzyme, participates in photosynthesis by fixing CO2 in C4 plants. In this study, we aimed to understand the drought-tolerance mechanism of C4 PEPC transgenic rice with high photosynthetic efficiency. C4 PEPC transgenic rice plants (PC) and wild-type rice plants (WT) at the 4-5 leaf age were used. Using 15% polyethylene glycol-6000 (PEG) treatment for different days, we investigated leaf relative water content (RWC), net photosynthetic rate (Pn), protein kinase activity, PEPCase activity and PEPC gene expression in leaves of rice plants with different concentrations of CaCl2. RWC of PC leaf was enhanced with 0.5 mmol∙L-1 CaCl2 (P<0.05) except under 2 and 10 mmol∙L-1 CaCl2, and factors in the WT were unaffected by exogenous CaCl2. Pn of PC was not affected by CaCl2 treatments combined with 15% PEG. Moreover, PC showed an certain capacity for maintenance and stabilization of endogenous Ca2+ level in leaves under PEG treatment: with higher exogenous Ca2+ treatment (10 mmol∙L-1), PEPCase activity, PEPC expression and soluble protein were all decreased in PC leaves.