Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine of Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, No.151, Malianwa North Road, Haidian District, Beijing, 100193, China.
Plant Cell Rep. 2018 Jul;37(7):1061-1075. doi: 10.1007/s00299-018-2291-8. Epub 2018 May 23.
Key genes involved in metabolism and signalling of abscisic acid and gibberellins during Epimedium pseudowushanense B.L.Guo seed morphophysiological dormancy release were identified using phytochemistry, transcriptomics, and bioinformatic methods. The molecular mechanism of seed morphophysiological dormancy of Epimedium pseudowushanense B.L.Guo. remains largely unknown. The endogenous abscisic acid (ABA) and gibberellin (GA) content of E. pseudowushanense seeds at three developmental stages were quantitatively determined. The results showed the levels of ABA in E. pseudowushanense seeds decreased during seed embryo growth and development, while levels of GA increased during seed embryo growth, and levels of GA increased during seed dormancy release and seed sprouting. A high-throughput sequencing method was used to determine the E. pseudowushanense seed transcriptome. The transcriptome data were assembled as 178,613 unigenes and the numbers of differentially expressed unigenes between the seed development stages were compared. Computer analysis of reference pathways revealed that 12 candidate genes were likely to be involved in metabolism and signalling of ABA and GAs. The expression patterns of these genes were revealed by real-time quantitative PCR. Phylogenetic relationships among the deduced E. pseudowushanense proteins and their homologous proteins in other plant species were analysed. The results indicated that EpNCED1, EpNCED2, EpCYP707A1, and EpCYP707A2 are likely to be involved in ABA biosynthesis and catabolism. EpSnRK2 is likely implicated in ABA signalling during seed dormancy. EpGA3ox is likely to be involved in GA biosynthesis. EpDELLA1 and EpDELLA2 are likely implicated in GA signalling. This study is the first to provide the E. pseudowushanense seed transcriptome and the key genes involved in metabolism and signalling of ABA and GAs, and it is valuable for studies on the mechanism of seed morphophysiological dormancy.
采用植物化学、转录组学和生物信息学方法，鉴定了参与淫羊藿种子形态生理休眠解除过程中脱落酸和赤霉素代谢和信号转导的关键基因。淫羊藿种子形态生理休眠的分子机制在很大程度上尚不清楚。定量测定了三个发育阶段淫羊藿种子的内源脱落酸（ABA）和赤霉素（GA）含量。结果表明，淫羊藿种子 ABA 水平在种子胚胎生长发育过程中降低，而 GA 水平在种子胚胎生长过程中增加，在种子休眠解除和种子萌发过程中增加。采用高通量测序方法测定淫羊藿种子转录组。将转录组数据组装为 178613 条 unigenes，并比较了种子发育阶段之间差异表达 unigenes 的数量。参考途径的计算机分析表明，12 个候选基因可能参与 ABA 和 GAs 的代谢和信号转导。通过实时定量 PCR 揭示了这些基因的表达模式。分析了推导的淫羊藿蛋白与其他植物物种同源蛋白之间的系统发育关系。结果表明，EpNCED1、EpNCED2、EpCYP707A1 和 EpCYP707A2 可能参与 ABA 的生物合成和分解代谢。EpSnRK2 可能参与种子休眠过程中的 ABA 信号转导。EpGA3ox 可能参与 GA 的生物合成。EpDELLA1 和 EpDELLA2 可能参与 GA 信号转导。本研究首次提供了淫羊藿种子转录组和参与 ABA 和 GAs 代谢和信号转导的关键基因，为研究种子形态生理休眠机制提供了有价值的信息。
