1. ¹National Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, and Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
2. ²School of Life Science and Biotechnology, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030, China
3. ³Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200433, China

Correspondence: Da LUO, Fax: +86-21-5492-4106; E-mail: dluo@sibs.ac.cn

Received 31 May 2005; Revised 28 July 2005; Accepted 11 August 2005.

Abstract

Recent studies on leaf development demonstrate that the mechanism on the adaxial-abaxial polarity pattern formation could be well conserved among the far-related species, in which PHANTASTICA (PAHN)-like genes play important roles. In this study, we explored the conservation and diversity on functions of PHAN-like genes during the compound leaf development in Lotus japonicus, a papilionoid legume. Two PHAN-like genes in L. japonicus, LjPHANa and LjPHANb, were found to originate from a gene duplication event and displayed different expression patterns during compound leaf development. Two mutants, reduced leaflets1 (rel1) and reduced leaflets3 (rel3), which exhibited decreased adaxial identity of leaflets and reduced leaflet initiation, were identified and investigated. The expression patterns of both LjPHANs in rel mutants were altered and correlated with abnormalities of compound leaves. Our data suggest that LjPHANa and LjPHANb play important but divergent roles in regulating adaxial-abaxial polarity of compound leaves in L. japonicus.