Structural characterization and expression pattern analysis of the rice PLT gene family.

Plethora (PLT) genes encode transcription factors containing AP2-domain, and have been shown to maintain the activity of stem cells and regulate the root development of dicot Arabidopsis thaliana. Through genome-wide analysis, 10 OsPLT members were identified in monocot rice. Quantitative real-time polymerase chain reaction analysis of the expression patterns of these OsPLT genes showed that OsPLTs1-5, OsPLTs7-9, and OsPLT10 were preferentially expressed in root, stem, or seed, respectively, and OsPLT6 was preferentially expressed both in root and seed. Further analysis by in situ hybridization showed that six root-expressed OsPLT genes (1-6) were all expressed in the primodium of crown root, and most of them were expressed in the initial cells adjacent to quiescent center of primary, crown, and lateral roots. In addition, OsPLT genes were regulated by multiple hormones, suggesting that OsPLTs might play an important role in the regulation of hormone-mediated development of main, crown, and lateral roots of rice.