PHOTOSYNTHETICA

Photosynthetica 2017, 55(4):630-637 | DOI: 10.1007/s11099-016-0682-z

Overexpression of calmodulin gene fragment from Antarctic notothenioid fish improves chilling tolerance in Nicotiana benthamiana

T. J. Zhang¹, L. J. Pan¹, Q. Huang¹, L. H. Zhu¹, N. Yang¹, C. L. Peng^1,*, L. B. Chen^2,*

¹ Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, College of Life Sciences, South China Normal University, Guangzhou, China

² Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China

Calmodulin (CaM) is a highly conserved calcium sensor protein associated with chilling tolerance in living organisms. It has four EF-hand domains for binding of four Ca²⁺, two of them located in the N-terminus, and the other two in the C-terminus. A notothenioid CaM gene fragment (CaMm), which only codes for N-terminus of CaM (with two EF-hand domains), was introduced into Nicotiana benthamiana. Effects of its overexpression on chilling tolerance in plants were explored. During 4◦C or 0◦C chilling treatment, both CaMm and CaM transgenic plants showed higher PSII maximum quantum yield, actual quantum yield, and soluble protein content, lower electrolyte leakage and malondialdehyde content than that of the control. The changes in these physiological indices were comparable between the CaMm and CaM transgenic plants during the treatments. These results indicate that the N-terminus of calmodulin is likely the key functional domain involved in the adaptive response to cold stress.

Additional key words: calcium-binding protein; chilling stress; chlorophyll fluorescence; electrolyte leakage; transgenic plants

Received: July 3, 2016; Accepted: October 10, 2016; Published: December 1, 2017  Show citation