ABSTRACT: Identification of genes involved in metabolism and signaling of abscisic acid and gibberellins during Epimedium pseudowushanense B.L.Guo seed morphophysiological dormancy
Project description:The molecular mechanism of seed morphophysiological dormancy of Epimedium pseudowushanense B.L.Guo. remains largely unknown. The endogenous ABA and GA content of E. pseudowushanense seeds at three developmental stages was quantitatively determined. The result showed the levels of ABA in E. pseudowushanense seeds decreased during the seed embryo growing and development, levels of GA3 increased during seed embryo growing, and levels of GA4 increased during seed dormancy releasing and seed sprouting. High-throughput sequencing method was used for reveal 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. By computer analysis of the KEGG reference pathways, twelve candidate genes were likely to be involved in metabolism and signaling of abscisic acid and gibberellins. The expression patterns of these genes were revealed by real-time quantitative RT-PCR. Phylogenetic relationships among the deduced E. pseudowushanense proteins and their homologous in other plant species were analyzed. The results indicate EpNCED1, EpNCED2, EpCYP707A1 and EpCYP707A2 are likely to be involved in ABA biosynthesis and catabolism. EpSnRK2 is likely implicated in ABA signaling during seed dormancy. EpGA3ox is likely to be involved in gibberellin biosynthesis, and EpDELLA1 and EpDELLA2 are likely implicated in GA signaling. This study was the first to provide the E. pseudowushanense seed transcriptome and the key genes involved in metabolism and signaling of abscisic acid and gibberellins, and so it is valuable for studies on seed morphophysiological dormancy mechanism
Project description:Seed germination is a major step of plant growth and development. It is critical for species competition and spreading capacity in ecosystems. In agrosystems, it eventually impacts crop growth and yield. To prevent unappropriated germination under environmental conditions that do not guarantee the establishment of a robust plantlet, seeds from temperate species are generally dormant at maturity. Dormancy is a physiological mechanism that blocks seed germination even under favorable conditions and dormancy release is therefore required prior to germination [1]. A range of environmental (e.g. temperature, light, oxygen availability) and endogenous (e.g. hormonal) signals regulate these processes and germination completion, i.e. the early emergence of embryo radicle from seed envelope, can be achieved only when promoting mechanisms overcome inhibiting processes [2]. In that sense, the balance between the two antagonistic hormones abscisic acid (ABA) and gibberellins (GA), that inhibit and stimulate seed germination, respectively, promotes either dormancy (high ABA and low GA contents) or germination (low ABA and high GA contents) [3]
