Molecular and Functional Characterization of PEBP Genes in Barley Reveal the Diversification of Their Roles in Flowering
Molecular and Functional Characterization of PEBP Genes in Barley Reveal the Diversification of Their Roles in Flowering
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DOI：
10.1104/pp.108.132134
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发表时间：
2009-03-01
期刊：
影响因子：
7.4
通讯作者：
Handa, Hirokazu
中科院分区：
文献类型：
--
作者：
Kikuchi, Rie;Kawahigashi, Hiroyuki;Handa, Hirokazu
5大麦（大麦）PEBP（磷脂酰乙醇胺结合蛋白）基因进行了分析，以澄清其功能的作用，在开花转基因，表达和数量性状位点分析。将HvTFL 1和HvMFT 1导入水稻植株中并没有导致开花的任何变化，这表明这两个基因具有与开花不同的功能。在水稻中过量表达HvFT 1、HvFT 2和HvFT 3导致水稻提前抽穗，表明这些FT样基因可以作为成花转变的启动子。HvFT 1转基因植物表现出最强的开花起始。在大麦中，HvFT 1在芽分生组织相变时表达。这些结果表明，HvFT 1是大麦FT-类基因家族中负责开花的关键基因。HvFT 2转基因植物也表现出强大的开花启动，但HvFT 2只在短日照（SD）条件下表达的相变过程中，这表明它的作用是有限的，在大麦特定的光周期条件。HvFT 3转基因水稻的开花活性没有那么强，并且受到光周期的调节。这些结果表明，HvFT 3的功能，在开花促进，但其效果是间接的。HvFT 3的表达，观察到在Morex，大麦品种携带显性等位基因的Ppd-H2，一个主要的数量性状基因座开花SD条件下，虽然没有检测到Steptoe，一个品种携带Ppd-H2。HvFT 3在长日照和SD条件下均在Morex中表达，尽管其表达在SD条件下增加。HvFT 3定位于染色体1HL，与携带Ppd-H2的染色体相同。基因组序列分析显示，Morex拥有一个完整的HvFT 3基因，而这个基因的大部分已经失去了Steptoe。这些数据强烈表明HvFT 3可能与Ppd-H2相同。
Five barley (Hordeum vulgare) PEBP (for phosphatidylethanolamine-binding protein) genes were analyzed to clarify their functional roles in flowering using transgenic, expression, and quantitative trait locus analyses. Introduction of HvTFL1 and HvMFT1 into rice (Oryza sativa) plants did not result in any changes in flowering, suggesting that these two genes have functions distinct from flowering. Overexpression of HvFT1, HvFT2, and HvFT3 in rice resulted in early heading, indicating that these FT-like genes can act as promoters of the floral transition. HvFT1 transgenic plants showed the most robust flowering initiation. In barley, HvFT1 was expressed at the time of shoot meristem phase transition. These results suggest that HvFT1 is the key gene responsible for flowering in the barley FT-like gene family. HvFT2 transgenic plants also showed robust flowering initiation, but HvFT2 was expressed only under short-day (SD) conditions during the phase transition, suggesting that its role is limited to specific photoperiodic conditions in barley. Flowering activity in HvFT3 transgenic rice was not as strong and was modulated by the photoperiod. These results suggest that HvFT3 functions in flowering promotion but that its effect is indirect. HvFT3 expression was observed in Morex, a barley cultivar carrying a dominant allele of Ppd-H2, a major quantitative trait locus for flowering under SD conditions, although no expression was detected in Steptoe, a cultivar carrying ppd-H2. HvFT3 was expressed in Morex under both long-day and SD conditions, although its expression was increased under SD conditions. HvFT3 was mapped to chromosome 1HL, the same chromosome that carries Ppd-H2. Genomic sequence analyses revealed that Morex possesses an intact HvFT3 gene, whereas most of this gene has been lost in Steptoe. These data strongly suggest that HvFT3 may be identical to Ppd-H2.