Agronomy, Horticulture, and Plant Science Department, South Dakota State University, Brookings, South Dakota, 57007, USA.
Agricultural College, South China Agricultural University, Guangzhou, 510642, China.
Sci Rep. 2018 Nov 14;8(1):16813. doi: 10.1038/s41598-018-34850-5.
Association between seed dormancy (SD) and flowering time (FT) may generate a synergy in plant adaptation. This research aimed to identify patterns and underlying genes of the association in rice (Oryza sativa). Four F and two BCF populations from crosses of weedy/cultivated rice, and two families of progeny lines from backcrosses were evaluated for variations in time to flowering and germination ability. The two measurements were correlated negatively in the F and BCF populations, but positively in advanced generations of the progeny lines. The negative correlations were resulted from linkage disequilibria between SD and FT loci at 7-40 cM apart. The positive correlations arose from co-located SD and FT loci undetectable in the BCF population. Two independent sets of co-localized loci were isolated as single Mendelian factors, and haplotypes that promote flowering and reduce germination derived from weedy and cultivated rice, respectively. The presence of negative and positive correlations indicates that the rice complex has maintained two contrasting patterns of SD-FT coadaptation, with the positive being "recessive" to the negative pattern. Modeling with isogenic lines suggests that a negative pattern could generate a greater synergy (difference between haplotype variants) than the positive one for seedbank persistence, or enhanced plant adaptation to seasonal changes in temperature or moisture. However, the early-flowering dormant genotype of a positive pattern could also have a selective advantage over its counterpart for weeds to avoid harvesting. The isolated haplotypes could be used to manipulate cultivars simultaneously for germination ability and growth duration.
种子休眠（SD）和开花时间（FT）之间的关联可能会在植物适应中产生协同作用。本研究旨在鉴定水稻（Oryza sativa）中这种关联的模式和潜在基因。从杂草/栽培稻杂交中评估了四个 F 和两个 BCF 群体，以及两个回交后代系群体的开花时间和发芽能力的变化。这两个测量值在 F 和 BCF 群体中呈负相关，但在后代系的高级世代中呈正相关。负相关是由于 SD 和 FT 基因座之间的连锁不平衡所致，这些基因座之间的距离为 7-40cm。正相关是由于在 BCF 群体中无法检测到 SD 和 FT 基因座的共定位引起的。分离出了两组独立的共定位基因座，作为单孟德尔因子，以及分别来自杂草和栽培稻的促进开花和减少发芽的单倍型。负相关和正相关的存在表明，水稻复合体维持了两种截然不同的 SD-FT 协同适应模式，其中正相关模式是负相关模式的“隐性”。用同基因系进行建模表明，对于种子库的持久性或增强植物对温度或水分季节性变化的适应能力，负相关模式比正相关模式产生更大的协同作用（单倍型变异之间的差异）。然而，正相关模式的早开花休眠基因型也可能对杂草具有选择性优势，以避免收获。分离出的单倍型可用于同时操纵品种的发芽能力和生长时间。
