Chinese Bulletin of Botany ›› 2015, Vol. 50 ›› Issue (2): 206-216.DOI: 10.3724/SP.J.1259.2015.00206

• EXPERIMENTAL COMMUNICATIONS • Previous Articles     Next Articles

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

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.