State Key Laboratory of Rice Biology, Key Laboratory of Rice Biology and Breeding of Ministry of Agriculture, China National Rice Research Institute, Hangzhou, 310006, China.
Plant Cell Rep. 2013 Sep;32(9):1455-63. doi: 10.1007/s00299-013-1457-7. Epub 2013 May 21.
A new rice floral organ mutant bh1 , had a negative effect on grain yield. BH1 was fine mapped to 87.5 kb on chr2. A 55 kb chromosome segment was deleted in bh1. The cereal spikelet is enclosed by the lemma and palea. The lemma and palea of the floral mutant designated bh1, a selection from a T-DNA library generated from the rice cultivar Asominori, takes on an abnormal curve-shaped appearance only late in floral development, finally forming a beak-shaped hull. The mutation had a negative effect on thousand grain weight, seed set rate and germination rate. Genetic analysis indicated that the mutant phenotype was determined by a single recessive gene. Through map-based approach, BH1 gene was finally located to a ~87.5-kbp region on the long arm of chromosome 2. An analysis of the gene content of this region indicated that the mutation involves the loss of a 55-kbp stretch, harboring four open reading frames. Transcription profiling based on qRT-PCR revealed that the genes OsMADS1, OsMADS14, OsMADS15, OsMADS18, REP1, CFO1, and DL, all of which are also involved in lemma and palea development and identity specification, were down-regulated in the bh1 mutant. BH1 is therefore an important floral organ development gene.
一个新的水稻花器官突变体 bh1 ，对粒产量有负面影响。BH1 被精细定位到 chr2 上的 87.5 kb 处。bh1 中缺失了一个 55kb 的染色体片段。谷物小穗被外稃和内稃包裹。花突变体 bh1 的外稃和内稃，是从水稻品种 Asominori 的 T-DNA 文库中选择出来的，在花发育后期只呈现出异常的曲线形状，最终形成喙状颖壳。该突变对千粒重、结实率和发芽率有负面影响。遗传分析表明，突变表型由单个隐性基因决定。通过图谱定位方法，最终将 BH1 基因定位到第 2 号染色体长臂上的一个约 87.5-kbp 区域。对该区域基因内容的分析表明，该突变涉及到一个 55-kbp 片段的缺失，该片段包含四个开放阅读框。基于 qRT-PCR 的转录谱分析显示，bh1 突变体中下调了也参与外稃和内稃发育和身份特化的基因 OsMADS1、OsMADS14、OsMADS15、OsMADS18、REP1、CFO1 和 DL。因此，BH1 是一个重要的花器官发育基因。
