Overexpression of TCP transcription factor OsPCF7 improves agronomic trait in rice

Abstract

Plant morphogenetic regulation is an important part of plant development biology. An ideal plant architecture can be created to allow plant to fully capture and use solar energy and maximize rice yields per unit area. The TCP (THEOSINTE BRANCHCHED1-CYCLOIDEA-PROLIFERATING CELL FACTOR1) family transcription factors participate in plant developmental processes associated with cell proliferation and growth. In this study, OsPCF7 gene was isolated from Oryza sativa L., which encodes a class II TCP protein with 270 amino acids. The qPCR analysis showed that OsPCF7 expressed in all tissues and organs at all times. The expressions of OsPCF7 in the tiller stage were dramatically increased, and OsPCF7 protein was predominately targeted to the nucleus. The overexpression of OsPCF7 increased shoot height, root length, and total root number of transgenic rice seedlings and promoted the tiller and heading of rice plant, causing increase of panicle numbers and filled grain numbers per plant, finally leading to increase of grain yield per plant. In addition, OsPCF7 could positively regulate the expression of STM, KNAT2, KNAT6, LOX2, AS1, and IAA3 in overexpressing OsPCF7 plant. By contrast, RNAi of OsPCF7 decreased the tiller, panicle numbers, filled grain numbers, and grain yield per plant. RNAi of OsPCF7 also led to a significant decrease in the expression of STM, KNAT2, KNAT6, LOX2, AS1, and IAA3. Taken together, OsPCF7 played multiple roles in rice plant architecture by regulating different biological processes during rice growth and development, which made it a potential gene in genetic improvement for agronomic trait of crops.