Flowering time and photoperiod sensitivity in rice: Key players and their interactions identified
Kutubuddin A. Molla
Abstract
Rice is one of the most important cereal crops and has wide adaptability in diverse climatic regions ranging from 44 N to 35 S and 6 ft below to 2,700 ft above sea level Which traits and mechanisms confer this adaptability is a major question in rice biology. Heading date (or flowering time) is a crucial trait for the regional and seasonal adaptation of rice and influences grain yield. Rice is a facultative short-day (SD) plant; SD conditions promote, and long-day (LD) conditions inhibit flowering. On receiving day-length signals, leaf cells produce a mobile flowering activator, florigen, that is transported to the shoot apex to initiate the flowering transition. In rice, Heading date 3a (Hd3a) and RICE FLOWERING LOCUS T 1 (RFT1) are the two proposed florigens, which function under SD and LD conditions, respectively Transport of Hd3a from leaves to the shoot apex is essential for flowering under SD conditions. However, how this transport occurs and what factors facilitate the movement of Hd3a are unknown. In this issue, Liang Zhang and colleagues (Zhang et al., 2022) identified proteins responsible for florigen trafficking through the phloem from the leaves, where it is synthesized, to the shoot apex, where flower development occurs.