¹Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.

Correspondence: Jia Yang LI, Tel: 0086-10-64852855, Fax: 0086-10-64873428, E-mail: jyli@genetics.ac.cn

^*These authors contributed equally to this work.

Received 8 September 2003; Revised 30 October 2003; Accepted 6 November 2003.

Abstract

RAV1 is a novel DNA-binding protein with two distinct DNA-binding domains unique in higher plants, but its role in plant growth and development remains unknown. Using cDNA array, we found that transcription of RAV1 is down-regulated by epibrassinolide (epiBL) in Arabidopsis suspension cells. RNA gel blot analysis revealed that epiBL-regulated RAV1 transcription involves neither protein phosphorylation/dephosphorylation nor newly synthesized protein, and does not require the functional BRI1, suggesting that this regulation might be through a new BR signaling pathway. Overexpressing RAV1 in Arabidopsis results in a retardation of lateral root and rosette leaf development, and the underexpression causes an earlier flowering phenotype, implying that RAV1 may function as a negative regulatory component of growth and development.