Cloning of quantitative trait genes from rice reveals conservation and divergence of photoperiod flowering pathways in Arabidopsis and rice.

Kazuki Matsubara,Masahiro Yano,Kiyosumi Hori,Eri Ogiso-Tanaka

doi:10.3389/fpls.2014.00193

Abstract

Flowering time in rice (Oryza sativa L.) is determined primarily by daylength (photoperiod), and natural variation in flowering time is due to quantitative trait loci involved in photoperiodic flowering. To date, genetic analysis of natural variants in rice flowering time has resulted in the positional cloning of at least 12 quantitative trait genes (QTGs), including our recently cloned QTGs, Hd17, and Hd16. The QTGs have been assigned to specific photoperiodic flowering pathways. Among them, 9 have homologs in the Arabidopsis genome, whereas it was evident that there are differences in the pathways between rice and Arabidopsis, such that the rice Ghd7–Ehd1–Hd3a/RFT1 pathway modulated by Hd16 is not present in Arabidopsis. In this review, we describe QTGs underlying natural variation in rice flowering time. Additionally, we discuss the implications of the variation in adaptive divergence and its importance in rice breeding.

Highlights

Photoperiodic flowering is one of the most important responses of plants to their environment (Thomas and Vince-Prue, 1997)
We describe the molecular basis of quantitative trait genes (QTGs) underlying natural variation in rice flowering time and discuss the implications on adaptive divergence and consequences for breeding
Regulation of the Hd1–Hd3a pathway is mediated by OsGI, a rice homolog of GI (Hayama et al, 2003). These findings reveal that a floral induction pathway from GI to FLOWERING LOCUS T (FT) in photoperiodic flowering is conserved between Arabidopsis (LD) and rice (SD), but that the photoperiod response differs between these plants

Summary

Introduction

Photoperiodic flowering is one of the most important responses of plants to their environment (Thomas and Vince-Prue, 1997). MOLECULAR BASIS OF NATURAL VARIATION IN RICE FLOWERING A genetic pathway resembling that the photoperiod pathway in Arabidopsis [a long-day (LD) plant] is conserved in rice. Hd1 regulates Hd3a, a rice homolog of Arabidopsis FLOWERING LOCUS T (FT) (Kojima et al, 2002) (Figure 1).

Results

Conclusion