Exogenous auxin regulates multi-metabolic network and embryo development, controlling seed secondary dormancy and germination in Nicotiana tabacum L.

BMC Plant Biology

Research Article

Jianhua Wang¹  Zhenhua Li²  Guoying Wang³  Junjie Fu³  Yiling Liu⁴  Xueliang Ren⁵  Jie Zhang⁵  Jiehong Zhao⁵ 

[1] College of Agriculture and Biotechnology, China Agricultural University, Yuanmingyuan West Road, 100094, Beijing, China;College of Agriculture and Biotechnology, China Agricultural University, Yuanmingyuan West Road, 100094, Beijing, China;Molecular Genetics Key Laboratory of China Tobacco, Guizhou Academy of Tobacco Science, 550081, GuiYang, China;Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, 100081, Beijing, China;Institute of Tobacco, Guizhou University, 550025, Guiyang, China;Molecular Genetics Key Laboratory of China Tobacco, Guizhou Academy of Tobacco Science, 550081, GuiYang, China;

关键词: Auxin;    Seed dormancy;    Germination;    Wateruptake;    Embryo development;    Endosperm burst;    Hormone;    Nicotiana tabacum;    RNA-seq;   

DOI  :  10.1186/s12870-016-0724-5

 received in 2015-10-15, accepted in 2016-01-28,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundAuxin was recognized as a secondary dormancy phytohormone, controlling seed dormancy and germination. However, the exogenous auxin-controlled seed dormancy and germination remain unclear in physiological process and gene network.ResultsTobacco seeds soaked in 1000 mg/l auxin solution showed markedly decreased germination compared with that in low concentration of auxin solutions and ddH2O. Using an electron microscope, observations were made on the seeds which did not unfold properly in comparison to those submerged in ddH2O. The radicle traits measured by WinRHIZO, were found to be also weaker than the other treatment groups. Quantified by ELISA, there was no significant difference found in β-1,3glucanase activity and abscisic acid (ABA) content between the seeds imbibed in gradient concentration of auxin solution and those soaked in ddH2O. However, gibberellic acid (GA) and auxin contents were significantly higher at the time of exogenous auxin imbibition and were gradually reduced at germination. RNA sequencing (RNA-seq), revealed that the transcriptome of auxin-responsive dormancy seeds were more similar to that of the imbibed seeds when compared with primary dormancy seeds by principal component analysis. The results of gene differential expression analysis revealed that auxin-controlled seed secondary dormancy was associated with flavonol biosynthetic process, gibberellin metabolic process, adenylyl-sulfate reductase activity, thioredoxin activity, glutamate synthase (NADH) activity and chromatin regulation. In addition, auxin-responsive germination responded to ABA, auxin, jasmonic acid (JA) and salicylic acid (SA) mediated signaling pathway (red, far red and blue light), glutathione and methionine (Met) metabolism.ConclusionsIn this study, exogenous auxin-mediated seed secondary dormancy is an environmental model that prevents seed germination in an unfavorable condition. Seeds of which could not imbibe normally, and radicles of which also could not develop normally and emerge. To complete the germination, seeds of which would stimulate more GA synthesis to antagonize the stimulation of exogenous auxin. Exogenous auxin regulates multi-metabolic networks controlling seed secondary dormancy and germination, of which the most important thing was that we found the auxin-responsive seed secondary dormancy refers to epigenetic regulation and germination to enhance Met pathway. Therefore, this study uncovers a previously unrecognized transcriptional regulatory networks and physiological development process of seed dormancy and germination with superfluous auxin signal activate.

【 授权许可】

CC BY   
© Li et al. 2016