GAMYB-like genes, flowering, and gibberellin signaling in Arabidopsis
GAMYB-like genes, flowering, and gibberellin signaling in Arabidopsis
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DOI：
10.1104/pp.010442
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发表时间：
2001-12-01
期刊：
影响因子：
7.4
通讯作者：
King, RW
中科院分区：
文献类型：
--
作者：
Gocal, GFW;Sheldon, CC;King, RW
我们已经鉴定了三个拟南芥基因，AtMYB 33，AtMYB 65，和AtMYB 101，可以取代大麦（大麦）的反式激活大麦α-淀粉酶启动子的GAMYB的类似活动。我们研究了赤霉素（GAs），这些GAMB-like基因，和叶柄伸长和开花的拟南芥之间的关系。在1 ~ 2 d内，从短日照到长日照的转换植株，叶柄的生长速度和直立度增加，并有形态变化，在茎尖与过渡到开花。这些反应伴随着GAs在叶柄中的积累（GA（1）为11倍，GA（4）为3倍），以及AtMYB 33在茎尖的表达增加。用多效唑抑制赤霉素的生物合成可以阻断长日照诱导的叶柄伸长。结果表明，GA处理，植物在短时间内开花，AtMYB 33的表达在茎尖增加，叶柄伸长，直立生长。AtMYB 33可能介导开花中的GA信号传导作用，这是由其结合到花分生组织身份基因LEAFY的启动子中的特定8-bp序列的能力支持的，该相同序列在LEAFY启动子的GA响应中是重要的。这些AtMYB基因中的一个或多个也可能在萌发过程中的根尖中发挥作用，然后在茎组织中发挥作用。这些发现扩展了我们早期对禾本科植物GA信号转导的研究，包括双子叶植物拟南芥，并表明GAMYB样基因可能在生长和开花反应中介导GA信号转导。
We have identified three Arabidopsis genes with GAMYB-like activity, AtMYB33, AtMYB65, and AtMYB101, which can substitute for barley (Hordeum vulgare) GAMYB in transactivating the barley a-amylase promoter. We have investigated the relationships between gibberellins (GAs), these GAMYB-like genes, and petiole elongation and flowering of Arabidopsis. Within 1 to 2 d of transferring plants from short- to long-day photoperiods, growth rate and erectness of petioles increased, and there were morphological changes at the shoot apex associated with the transition to flowering. These responses were accompanied by accumulation of GAs in the petioles (GA(1) by 11-fold and GA(4) by 3-fold), and an increase in expression of AtMYB33 at the shoot apex. Inhibition of GA biosynthesis using paclobutrazol blocked the petiole elongation induced by long days. Causality was suggested by the finding that, with GA treatment, plants flowered in short days, AtMYB33 expression increased at the shoot apex, and the petioles elongated and grew erect. That AtMYB33 may mediate a GA signaling role in flowering was supported by its ability to bind to a specific 8-bp sequence in the promoter of the floral meristem-identity gene, LEAFY, this same sequence being important in the GA response of the LEAFY promoter. One or more of these AtMYB genes may also play a role in the root tip during germination and, later, in stem tissue. These findings extend our earlier studies of GA signaling in the Gramineae to include a dicot species, Arabidopsis, and indicate that GAMYB-like genes may mediate GA signaling in growth and flowering responses.