Apple Breeding and Physiology Research Team, National Institute of Fruit Tree Science, 92-24 Nabe-yashiki, Shimo-kuriyagawa, Morioka, 020-0123 Japan. k
Plant Cell Physiol. 2010 Apr;51(4):561-75. doi: 10.1093/pcp/pcq021. Epub 2010 Feb 25.
The two FLOWERING LOCUS T (FT)-like genes of apple (Malus x domestica Borkh.), MdFT1 and MdFT2, have been isolated and characterized. MdFT1 and MdFT2 were mapped, respectively, on distinct linkage groups (LGs) with partial homoeology, LG 12 and LG 4. The expression pattern of MdFT1 and MdFT2 differed in that MdFT1 was expressed mainly in apical buds of fruit-bearing shoots in the adult phase, with little expression in the juvenile tissues, whereas MdFT2 was expressed mainly in reproductive organs, including flower buds and young fruit. On the other hand, both genes had the potential to induce early flowering since transgenic Arabidopsis, which ectopically expressed MdFT1 or MdFT2, flowered earlier than wild-type plants. Furthermore, overexpression of MdFT1 conferred precocious flowering in apple, with altered expression of other endogenous genes, such as MdMADS12. These results suggest that MdFT1 could function to promote flowering by altering the expression of those genes and that, at least, other genes may play an important role as well in the regulation of flowering in apple. The long juvenile period of fruit trees prevents early cropping and efficient breeding. Our findings will be useful information to unveil the molecular mechanism of flowering and to develop methods to shorten the juvenile period in various fruit trees, including apple.
已分离并鉴定了苹果（Malus x domestica Borkh.）中的两个拟南芥 FLOWERING LOCUS T（FT）样基因 MdFT1 和 MdFT2。MdFT1 和 MdFT2 分别被定位在具有部分同源性的不同连锁群（LG）上，LG12 和 LG4。MdFT1 和 MdFT2 的表达模式不同，MdFT1 主要在成年期果实生长枝的顶芽中表达，在幼年组织中表达很少，而 MdFT2 主要在生殖器官中表达，包括花芽和幼果。另一方面，由于转 MdFT1 或 MdFT2 的拟南芥比野生型植物更早开花，这两个基因都有可能诱导早期开花。此外，MdFT1 的过表达导致苹果提前开花，改变了其他内源性基因，如 MdMADS12 的表达。这些结果表明，MdFT1 可以通过改变这些基因的表达来促进开花，至少其他基因在苹果开花调控中也可能发挥重要作用。果树的长幼期会阻碍早期结果和有效的繁殖。我们的发现将为揭示开花的分子机制以及开发缩短包括苹果在内的各种果树幼年期的方法提供有用的信息。
