Wheat miR9678 Affects Seed Germination by Generating Phased siRNAs and Modulating Abscisic Acid/Gibberellin Signaling

First author: Guanghui Guo; Affiliations: China Agricultural University (中国农业大学): Beijing, China

Corresponding author: Yingyin Yao (姚颖垠)

Seed germination is important for grain yield and quality and rapid, near-simultaneous (几乎同时) germination helps in cultivation (栽培); however, cultivars (栽培品种) that germinate too readily (快捷地) can undergo pre-harvest sprouting (PHS; 穗发芽), which causes substantial losses in areas that tend to get rain around harvest time. Moreover, our knowledge of mechanisms regulating seed germination in wheat (Triticum aestivum) remains limited. In this study, we analyzed function of a wheat-specific microRNA 9678 (miR9678), which is specifically expressed in the scutellum (盾片，内子叶) of developing and germinating seeds. Overexpression of miR9678 delayed germination and improved resistance to PHS in wheat through reducing bioactive gibberellins (GAs) levels; miR9678 silencing enhanced germination rates. We provide evidence that miR9678 targets a long non-coding RNA (WSGAR) and triggers the generation of phased siRNA which play a role in the delay of seed germination. Finally, we found that abscisic acid (ABA) signaling proteins bind the promoter of miR9678 precursor and activate its expression, indicating that miR9678 affects germination by modulating the GA/ABA signaling.

种子发芽对于籽粒产量和品质是非常重要的，且快速、一致的萌发对于栽培很有帮助。然而，能够轻易萌发的栽培品种在收获前会发芽，即穗发芽PHS，这对于一些在收获季节多雨的地区作物产量有极大损失。此外，目前对于小麦种子萌发的调控机制还了解的比较少。本研究分析了小麦特异的microRNA 9678，即miR9678，该miRNA在发育和萌发的种子内子叶中特异表达。过表达miR9678会通过减少具有生物活性赤霉素GA来延迟萌发，并提升小麦对于PHS的抗性；miR9678沉默增强萌发速率。作者的研究显示miR9678靶向一个长链非编码RNA，诱导一个在种子萌发延迟过程中扮演重要作用的phased siRNA的产生。最终，作者发现脱落酸ABA信号蛋白结合miR9678前体的启动子，并激活其表达，表明miR9678通过调控GA/ABA信号转导影响种子萌发。

通讯：姚颖垠 (http://cab.cau.edu.cn/art/2017/6/12/art_27218_151.html)

个人简介：1997-2001年，中国农业大学，植物遗传育种系，学士；2001-2005年，中国农业大学，植物遗传育种系，博士；2005-2007年，中国农业大学，植物遗传育种系，讲师；2005-2006年，美国加州大学RIVERSIDE分校，访问学者；2007-2013年，中国农业大学，植物遗传育种系，副教授／博导；2009-2011年，美国佐治亚大学，访问学者；2013-至今，中国农业大学农学院，教授／博导。

研究方向：小麦小分子RNA的功能解析及调控农艺性状形成的分子机制；小麦小分子RNA的功能解析及调控农艺性状形成的分子机制。

doi: https://doi.org/10.1105/tpc.17.0084

Journal: Plant Cell

First Published date: 22 March, 2018

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