CHARACTERIZATION OF OSFTIP9 IN REGULATING RICE TILLERING BEHAVIOUR

Abstract

Multiple C2 domain and transmembrane region proteins (MCTPs) are involved in macromolecular trafficking. In this study, we focused on investigation of one of the rice MCTPs, FT-INTERACTING PROTEIN 9 (OsFTIP9). We firstly generated loss-of-function mutant Osftip9-1, and revealed an increased number of secondary tillers in the mutant. Yeast two-hybrid screening identified Fine Culm 1 (FC1), a TCP family transcription factor, as an interacting partner of OsFTIP9. Consistently, the fc1 mutant showed the similar tillering phenotype to Osftip9-1. Furthermore, subcellular localization of FC1 in the nucleus was disturbed in Osftip9-1. We further found that the expression of the genes downstream of the tillering pathway was altered in Osftip9-1 and fc1. Taken together, our results suggest that OsFTIP9 plays important roles in stabilizing FC1 protein and mediating its transport into the nucleus, thus affecting the expression of FC1 downstream genes to regulate rice tillering behaviour.