SCL15 is a critical regulator for plant development, germination, seed dormancy and seed vigor in Arabidopsis thaliana. SCL15 is a critical regulator for plant development, germination, seed dormancy and seed vigor in Arabidopsis thaliana

Seed maturation, dormancy and germination are distinct physiological processes. Transition from maturation to dormancy, and from dormancy into germination are not only critical developmental phases in the plant life cycle but are also important agricultural traits. These developmental processes and their phase transitions are fine determined and coordinately regulated by genetic makeup and environmental cues. SCARECROW-LIKE15 (SCL15) has been demonstrated to be essential for repressing the seed maturation programme in vegetative tissues (Gao et al., Nat Commun, 2015, 6:7243). Here we report that SCL15 is also important for seed dormancy maintenance, germination timing and seed vigor performance based on the effects of SCL15 mutation on plant germination, growth and reproduction when compared with wild type Arabidopsis and over-expression lines 35S:SCL15 and Napin:SCL15. Seed dormancy is enhanced by the mutation of SCL15 in a GA signaling dependent way, indicating that SCL15 plays a negative role for primary dormancy release. Seed germination is positively regulated by SCL15 through interaction with ABA, GA and auxin signaling. SCL15 acts as positive regulator of seed vigor and effect of SCL15 mRNA abundance on seed reserve accumulation and seed development during late embryogenesis may contribute to the seed vigor performance. Overall design: We compared gene expression in three plant lines: Wild type, Scl15 knockout, and Scl15 seed-specific overexpression. For each line we sequenced 3 biological replicates.

种子成熟、休眠与萌发是三类相互独立的生理过程。从成熟向休眠的阶段过渡，以及从休眠向萌发的阶段过渡，不仅是植物生命周期中的关键发育节点，亦是重要的农艺性状。上述发育过程及其阶段转变，均由遗传背景与环境信号精细调控并协同执行。Scarecrow-like 15（SCL15）已被证实可在营养组织中抑制种子成熟程序，相关研究成果见于Gao等人2015年发表于《自然·通讯》的论文（卷6，文章编号7243）。本研究通过对比野生型拟南芥、过表达株系35S:SCL15与Napin:SCL15中SCL15基因突变对植物萌发、生长及繁殖的影响，证实SCL15同样在种子休眠维持、萌发时序调控与种子活力表现中发挥核心作用。SCL15基因突变可通过依赖赤霉素（Gibberellic acid, GA）信号通路的途径增强种子休眠，表明SCL15在初生休眠解除过程中充当负调控因子。SCL15可通过与脱落酸（Abscisic acid, ABA）、赤霉素（GA）及生长素信号通路的相互作用，正向调控种子萌发。SCL15作为种子活力的正向调控因子，其mRNA丰度对胚胎发生后期种子储备积累与发育的调控作用，或可参与调控种子活力表现。实验整体设计：本研究对三类植物株系的基因表达水平开展对比分析，分别为野生型拟南芥、Scl15基因敲除株系以及种子特异性过表达SCL15株系；每个株系设置3次生物学重复并进行转录组测序。