OsFT coordinates photosynthetic stability and carotenoid metabolism to regulate tillering in rice

Photosynthesis and tillering number have been essential components determining grain yield in rice. However, the genetic mechanism of carotenoid biosynthesis pathway, which is one of the photosynthetic pigments of rice, affecting tillering of rice is rarely studied.

This study elucidates the roles of OsFT in photosynthesis and carotenoid biosynthesis, and the synergistic regulation of rice tillering by SL and ABA, providing a theoretical basis for breeding high-yielding, drought-resistant rice varieties.

The OsFT gene was cloned using map-based cloning technology. Quantitative RT-PCR and RNA sequencing (RNA-seq) were conducted to identify differentially expressed genes. Molecular technologies, including yeast two-hybrid assay (Y2H), co-immunoprecipitation assay (Co-IP), bimolecular fluorescence complementation assays (BIFC), and LUC complementation imaging assay (LCI) were employed to investigate the physical interaction between OsFT and OsFtsh2. High-performance liquid chromatography (HPLC) was used to measure the levels of abscisic acid (ABA), strigolactone (SL), and all-trans-β-carotene in rice plants. Data for yield-related traits were statistically analyzed and processed using Microsoft Excel, and the data were analysed using GraphPad Prism version 9.

We report that OsFT interacts with the photosynthetic protein OsFtsh2 to maintain the stability of the photosynthetic system by regulating the degradation and renewal of photosynthetic protein, thus affecting photosynthetic efficiency and stress adaptability. It was found that OsFT regulates the expression of ABA and SL by influencing the carotenoid biosynthesis pathway, which in turn affects tillering. In addition, overexpression of OsFT enhances plant adaptability to drought stress and increases plant yield.

OsFT interacts with OsFtsH2 to maintain the stability of the photosynthetic system and affects tillering by regulating the expression of ABA and SL. Biological studies have found that overexpressing this gene can enhance the plant's drought tolerance and yield.