The Applied Plant Genomics Laboratory of Crop Genomics and Bioinformatics Center, and National Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095 Jiangsu, China.
J Exp Bot. 2013 Aug;64(11):3299-312. doi: 10.1093/jxb/ert183.
Rht-B1c, allelic to the DELLA protein-encoding gene Rht-B1a, is a natural mutation documented in common wheat (Triticum aestivum). It confers variation to a number of traits related to cell and plant morphology, seed dormancy, and photosynthesis. The present study was conducted to examine the sequence variations of Rht-B1c and their functional impacts. The results showed that Rht-B1c was partially dominant or co-dominant for plant height, and exhibited an increased dwarfing effect. At the sequence level, Rht-B1c differed from Rht-B1a by one 2kb Veju retrotransposon insertion, three coding region single nucleotide polymorphisms (SNPs), one 197bp insertion, and four SNPs in the 1kb upstream sequence. Haplotype investigations, association analyses, transient expression assays, and expression profiling showed that the Veju insertion was primarily responsible for the extreme dwarfing effect. It was found that the Veju insertion changed processing of the Rht-B1c transcripts and resulted in DELLA motif primary structure disruption. Expression assays showed that Rht-B1c caused reduction of total Rht-1 transcript levels, and up-regulation of GATA-like transcription factors and genes positively regulated by these factors, suggesting that one way in which Rht-1 proteins affect plant growth and development is through GATA-like transcription factor regulation.
Rht-B1c 是 DELLA 蛋白编码基因 Rht-B1a 的等位基因，在普通小麦（Triticum aestivum）中被记录为一种自然突变。它为许多与细胞和植物形态、种子休眠和光合作用相关的性状提供了变异性。本研究旨在研究 Rht-B1c 的序列变异及其功能影响。结果表明，Rht-B1c 对株高具有部分显性或共显性作用，并表现出增强的矮化效应。在序列水平上，Rht-B1c 与 Rht-B1a 的区别在于一个 2kb 的 Veju 反转录转座子插入、三个编码区单核苷酸多态性（SNP）、一个 197bp 的插入和 1kb 上游序列中的四个 SNP。单倍型研究、关联分析、瞬时表达分析和表达谱分析表明，Veju 插入是导致极端矮化效应的主要原因。研究发现，Veju 插入改变了 Rht-B1c 转录本的加工，导致 DELLA 基序一级结构破坏。表达分析表明，Rht-B1c 导致总 Rht-1 转录本水平降低，GATA 样转录因子及其正调控因子基因的上调，表明 Rht-1 蛋白影响植物生长和发育的一种方式是通过 GATA 样转录因子的调控。
