National Institute of Agricultural Botany, Huntingdon Rd, Cambridge, CB3 0LE, UK.
Theor Appl Genet. 2013 Jul;126(7):1733-47. doi: 10.1007/s00122-013-2088-7. Epub 2013 Apr 4.
The introduction of Reduced height (Rht)-B1b and Rht-D1b into bread wheat (Triticum aestivum) varieties was a key component of the 'green revolution' and today these alleles are the primary sources of semi-dwarfism in wheat. The Rht-1 loci encode DELLA proteins, which are transcription factors that affect plant growth and stress tolerance. In bread wheat, Rht-D1b and Rht-B1b influence resistance to the disease Fusarium Head Blight. To identify Rht-1 variants, locus specific primers were developed and used to sequence the entire open reading frame (ORF) and 1.7 kb of the 5' and 0.5 kb of the 3' flanking regions of Rht-A1 (Rht-A1+f), Rht-B1 (Rht-B1+f), and Rht-D1 (Rht-D1+f) in bread wheat (36 sequences from each genome) and tetraploid and diploid wheat (TDW) (one to three sequences from each genome). Among the bread wheat accessions, the Rht-A1+f and Rht-D1+f sequences contained relatively low genetic diversity and few haplotypes relative to the Rht-B1+f sequences. The TDW accessions were relatively rich in genetic diversity and contained the majority of the polymorphic sites. Novel polymorphisms, relative to 'Chinese Spring', discovered among the accessions include 160 and 197 bp insertions 5' of Rht-B1 and a frameshift in the Rht-B1 ORF. Quantitative real-time PCR using shoot and leaf tissue from 5-day-old seedlings of genotypes lacking or containing the 5' insertions revealed no major effect on Rht-B1 transcript accumulation. This research provides insights into the genetic diversity present at the Rht-1 loci in modern bread wheat and in relation to ancestral wheat accessions.
矮秆基因（Rht）-B1b 和 Rht-D1b 被引入到普通小麦（Triticum aestivum）品种中是“绿色革命”的关键组成部分，而如今这些等位基因是小麦半矮化的主要来源。Rht-1 基因座编码 DELLA 蛋白，这是一种转录因子，影响植物的生长和对胁迫的耐受性。在普通小麦中，Rht-D1b 和 Rht-B1b 影响对赤霉病的抗性。为了鉴定 Rht-1 变体，开发了特定于基因座的引物，并用于对普通小麦（36 个序列来自每个基因组）和四倍体和二倍体小麦（TDW）（每个基因组一个到三个序列）的 Rht-A1（Rht-A1+f）、Rht-B1（Rht-B1+f）和 Rht-D1（Rht-D1+f）的完整开放阅读框（ORF）和 5'侧翼区的 1.7 kb 和 3'侧翼区的 0.5 kb 进行测序。在普通小麦品种中，与 Rht-B1+f 序列相比，Rht-A1+f 和 Rht-D1+f 序列的遗传多样性相对较低，单倍型较少。TDW 品种的遗传多样性相对丰富，包含大多数多态性位点。与“中国春”相比，在这些品种中发现的新的多态性包括 Rht-B1 5' 处的 160 和 197 bp 插入和 Rht-B1 ORF 的移码。使用缺乏或含有 5' 插入的基因型的 5 天大幼苗的茎和叶组织进行的实时定量 PCR 显示，Rht-B1 转录物积累没有主要影响。这项研究提供了关于现代普通小麦和与祖先小麦品种中 Rht-1 基因座存在的遗传多样性的见解。
