通过调控 miR159 表达控制观赏鹤望兰（Sinningia speciosa）开花时间。
Flowering time control in ornamental gloxinia (Sinningia speciosa) by manipulation of miR159 expression.
机构信息
Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China.
出版信息
Ann Bot. 2013 May;111(5):791-9. doi: 10.1093/aob/mct034. Epub 2013 Feb 12.
BACKGROUND AND AIMS
Gloxinia (Sinningia speciosa) is a popular commercial plant for its attractive and colourful flowers. However, the genetic mechanism of flowering time regulation in gloxinia is largely unknown. Recent studies on model plants have elucidated that miR159 acts as a negative regulator of floral transition in short-day photoperiods. The aim of this study was to investigate whether genetic modification of miR159 expression can offer an effective approach for regulation of flowering characteristics in gloxinia.
METHODS
Transgenic gloxinia plants were generated that over-express or suppress miR159 by means an efficient Agrobacterium-mediated transformation system in order to study the effect of miR159 on flowering time. In addition, the full-length cDNA of gloxinia GAMYB (SsGAMYB) was also cloned, and was verified to be a target of miR159 by modified RNA ligase-mediated 5' rapid amplification of cDNA ends.
KEY RESULTS
Transgenic gloxinia plants that over-express or suppress miR159 exhibited significantly late or early flowering, respectively. During flower development, the expression level of miR159 was negatively correlated with SsGAMYB in gloxinia. MiR159-mediated SsGAMYB expression affected the expression levels of SsLEAFY (SsLFY) and three MADS-box genes (SsAP1, SsAP3 and SsAG), which regulated floral transition downstream of GAMYB. In addition, suppression of miR159 caused a conversion of petals and sepals in a few transgenic plants.
CONCLUSIONS
miR159-regulated GAMYB expression is an effective pathway of flowering time control in gloxinia. Transgenic manipulation of miR159 can be used as an applicable strategy to regulate flowering time in commercial ornamental plants.
背景与目的
大岩桐（Sinningia speciosa）因其花朵色彩鲜艳而受到欢迎，是一种常见的商业观赏植物。然而，大岩桐开花时间调控的遗传机制在很大程度上尚不清楚。最近对模式植物的研究表明，miR159 在短日照光周期中作为花转变的负调节剂发挥作用。本研究旨在探讨miR159 表达的遗传修饰是否可以为调控大岩桐开花特性提供一种有效方法。
方法
通过高效的农杆菌介导的转化系统，生成了过表达或抑制 miR159 的转基因大岩桐植物，以研究 miR159 对开花时间的影响。此外，还克隆了大岩桐 GAMYB（SsGAMYB）的全长 cDNA，并通过修饰的 RNA 连接酶介导的 5' 快速扩增 cDNA 末端验证其为 miR159 的靶标。
结果
过表达或抑制 miR159 的转基因大岩桐植物分别表现出明显的晚花或早花。在花发育过程中，miR159 的表达水平与大岩桐中的 SsGAMYB 呈负相关。miR159 介导的 SsGAMYB 表达影响了下游 GAMYB 的 SsLEAFY（SsLFY）和三个 MADS-box 基因（SsAP1、SsAP3 和 SsAG）的表达水平，调节花转变。此外，抑制 miR159 会导致少数转基因植物的花瓣和萼片发生转化。
结论
miR159 调控的 GAMYB 表达是大岩桐开花时间调控的有效途径。miR159 的转基因操作可作为调控商业观赏植物开花时间的应用策略。
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