Function analysis of PCAM in BR signal transduction
Xin Huang , Fengru Wang*,  JinGao Dong*

Laboratory of Molecular Phytopathology, Department of life science, Agricultural University of Hebei, Baoding, 071001.
*Corresponding Author：Tel: (+86) 0312-7526570;  E-mail: fengruwang@yahoo.com.cn

Abstract
To clarify the relationship between BR and Ca²⁺ signal transduction and their regulating mechanism in plant growth and development, 2D-DIGE technology combined with mass spectrometry analysis was used to identify proteins differentially expressed in d61-4(BR insensitive mutant in rice) and brd1-3(BR synthesis mutant in rice) in comparison with the wild type plant. A protein significantly upregulated both in d61-4 and brd1-3 was identified. The protein was related to Ca²⁺ signal transduction network (PCAM). This gene was overexpressed in Arabidopsis thaliana. Transgenic Arabidopsis lines overexpressing PCAM were smaller in size, and plant growth period was prolonged. The expression of SaurAC (a key gene in BR signal transduction pathway) in transgenic strains was obviously down-regulated. These results suggested a role of PCAM in the signal transduction of BR as a negative regulator of the plant growth and development.

Keywords:  PCAM; Brassinosteroids signal transduction;  Growth and development