Early flowering of the transgenic rice with AtNF-YB1

Abstract

Abstract Grain yield and growth period are two critical agronomic traits for a rice cultivar to be used in the field. The growth period is determined by flowering time, which also greatly affects grain yield. An Arabidopsis gene, AtNF-YB1, was introduced into rice, including Kasalath and two hybrids, Jinfeng X Chenghui 727 and Jinfeng XChuanhui 907. All the transgenic rice showed early flowering in both natural long-day (NLD) and natural short-day (NSD) conditions because of suppression of Ghd7 transcription resulting in early activating the flowering transition. The of pure line of Kasalath with the gene showed also shorter plant height and less grain yield with a decrease in spike length and grain number but more productive panicle. But, for the hybrids, a little or no reduction of spike length, grain number, and more productive panicles were observed so that grain yields were kept or even increased under NLD conditions. RNA-Seq further demonstrated that three pathways related to plant photosynthesis were markedly up-regulated in the transgenic Jinfeng B and hybrid Jinfeng X Chuanhui 907. Measurements of photosynthetic parameters indicated that photosynthetic rates were up-regulated with an increase of chlorophyll contents in the transgenic Jinfeng B and hybrid Jinfeng XChuanghui 907. The results suggest that AtNF-YB1could be useful for creating rice variety with early ripening, particularly for hybrid rice.