The Evolutionary Characterization Of LATERAL ORGAN BOUNDARIES Domain Gene Family In Rice

The plant specific LATERAL ORGAN BOUNDARIES (LOB) domain gene family has a potential role in lateral organ development. To investigate the evolutional)' characterization of the LOB domain (LBD) gene family in rice (OsLBD), 35 LBD genes in a japonica rice (Nipponbare) (designated OsJLBD) and in an indica rice (9311) (designated OslLBD), respectively, were identified based on the current databases of the two rice subspecies. Both OsJLBD and OslLBD genes can be classified into 2 classes (class I and class II) as LBD genes in Arabidopsis (AtLBD). A new rice LBD gene with two LOB domains and two predicted coiled coil structures in both subspecies was found, which is unique to rice. OsJLBD and OslLBD genes have similar chromosomal distribution pattern. Both OsJLBD and OslLBD genes can be divided into 5 subclasses (class Ia, Ib, Ic, Id, class II) and no subclass-specific expression pattern was observed. No intron has been predicted in all genes of class Id in both OsJLBD and OslLBD subfamilies. OsLBD gene families are characterized by subclasses parallel evolution and deletion of duplicated genes from Arabidopsis.