Functional Plant Research Unit, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan.
Laoratory of Plant Breeding &Genetics, Department of Agriculture, University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan.
Nat Plants. 2017 Mar 27;3:17039. doi: 10.1038/nplants.2017.39.
For genetically homogeneous crops, the timing of flowering is determined largely by the cultivation environment and is strongly associated with the yield and quality of the harvest. Flowering time and other agronomical traits are often tightly correlated, which can lead to difficulty excluding the effects of flowering time when evaluating the characteristics of different genetic varieties. Here, we describe the development of transgenic rice plants whose flowering time can be controlled by specific agrochemicals. We first developed non-flowering rice plants by overexpressing a floral repressor gene, Grain number, plant height and heading date 7 (Ghd7), to inhibit any environmentally induced spontaneous flowering. We then co-transformed plants with a rice florigen gene, Heading date 3a (Hd3a), which is induced by the application of specific agrochemicals. This permitted the flowering time to be experimentally controlled regardless of the cultivation environment: some transgenic plants flowered only after agrochemical treatment. Furthermore, plant size and yield-related traits could, in some cases, be increased owing to both a longer duration of vegetative growth and an increased panicle size. This ability to control flowering time experimentally, independently of environmental variables, may lead to production of crops suitable for growth in different climates and facilitate breeding for various agronomical traits.
对于遗传上同质的作物，开花时间主要由栽培环境决定，并且与收获的产量和质量密切相关。开花时间和其他农艺性状通常紧密相关，这可能导致在评估不同遗传品种的特性时，难以排除开花时间的影响。在这里，我们描述了通过特定农用化学品控制开花时间的转基因水稻植物的开发。我们首先通过过表达一个花抑制基因 Grain number, plant height and heading date 7 (Ghd7) 来开发非开花水稻植物，以抑制任何环境诱导的自发开花。然后，我们将水稻成花基因 Heading date 3a (Hd3a) 与植物共转化，该基因可被特定农用化学品诱导。这使得开花时间可以在实验上得到控制，而不受栽培环境的影响：一些转基因植物只有在农用化学品处理后才开花。此外，由于营养生长时间延长和穗数增加，一些情况下与植物大小和产量相关的性状也可以增加。这种独立于环境变量的实验控制开花时间的能力可能会导致生产适合在不同气候下生长的作物，并促进各种农艺性状的选育。
