State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China.
Theor Appl Genet. 2012 Oct;125(6):1303-12. doi: 10.1007/s00122-012-1914-7. Epub 2012 Jul 7.
Grain shape is an important component of end-use quality in rice. The genomic location of the grain shape QTL GS7 was narrowed to lie within a 4.8-kb segment on chromosome 7. The homologous region in cv. Nipponbare contains no annotated genes, while two open reading frames were predicted, one of which (ORF2) represented a likely candidate for GS7 gene on the basis of correlation between sequence variation and phenotype. Semi-quantitative and quantitative RT-PCR analysis of ORF2 transcription showed that the gene was active in both the leaf and panicle when the cv. D50 allele was present, but not in the presence of the cv. HB277 allele. A microsatellite-based phylogeny and a re-sequencing analysis of ORF2 among a set of 52 diverse rice accessions suggested that the cv. D50 GS7 allele may have originated from the tropical japonica genepool. The effect on grain length of the alternative alleles at GS7and GS3 showed that combination type 3/A was associated with longer grains than type 1/A. An Indel marker developed within the ORF2 sequence was informative for predicting grain length.
粒形是稻米食用品质的一个重要组成部分。粒形 QTL GS7 的基因组定位被缩小到第 7 号染色体上的 4.8kb 片段内。在品种 Nipponbare 中，同源区域没有注释基因，而预测出两个开放阅读框，其中一个（ORF2）根据序列变异与表型之间的相关性，代表了 GS7 基因的一个可能候选基因。对 ORF2 转录的半定量和定量 RT-PCR 分析表明，当存在品种 D50 等位基因时，该基因在叶片和穗中均有活性，但在存在品种 HB277 等位基因时则没有活性。基于微卫星的系统发育和一组 52 个不同水稻品种的 ORF2 重测序分析表明，品种 D50 的 GS7 等位基因可能起源于热带粳稻基因库。GS7 和 GS3 上的替代等位基因对粒长的影响表明，3/A 组合类型与 1/A 相比，粒长更长。在 ORF2 序列内开发的一个 Indel 标记可用于预测粒长。
