Brassinosteroids regulate disease-resistance through regulating the level of OsNDPK1
Shenghui Li, FengruWang, Jinghong Xing, Cangyue Wang, Xin Huang,  Shidong You, Haili Zhang, Fengru Wang*, Jingao Dong¹*

¹Molecular Plant Pathology Lab, College of Life Science, Agricultural University of Hebei, Baoding 071001, China.
*Corresponding Author：Tel: (+86) 0312-7528142; E-mail: fengruwang@yahoo.com.cn; Dongjingao@126.com.

Abstract
Brassinosteroids (BRs) were plant growth regulators, and played important roles in plant development. The function analysis of BR-regulating protein was the theory basis of clarifying how BR regulating plant growth and development. In this study, we identified some BR-regulated proteins using two-dimensional polyacrylamide gel electrophoresis, One of them is Nucleoside Diphosphate Kinase1 ( OsNDPK1 ). The level of OsNDPK1 was elevated after treated with BR in wide type rice and inhibited in BR-deficient rice mutant brd1-3 and d61-4. Then, we analyzed the function of OsNDPK1 through analyzing the phenotype of gaining-function transgenic Arabidopsis(OsNDPK1-OE). The results are as follows: OsNDPK1 is involved in the regulation of plant disease resistance. The ability of disease-resistance to plant pathogenic fungi- BotrytisCinerea (BC22) and pathogenic bacteria Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) was enhanced in over expression OsNDPK1 transgenic Arabidopsis thaliana. Over-expressioning OsNDPK1 could induce the expression of PAD4 and EDS1 which could promote SA accumulation and activated the defense pathway which induced by SA. These results opened up a new research approach for researching the mechanism of BR how to enhance the disease-resistance.

Keywords: Brassinosteroids; NDPK1; disease-resistance