Derkx Adinda P, Harding Carol A, Miraghazadeh Asemeh, Chandler Peter M
CSIRO Agriculture Flagship, GPO Box 1600, Canberra, ACT 2601, Australia.
Funct Plant Biol. 2017 May;44(5):525-537. doi: 10.1071/FP16262.
A suppressor screen using the dwarf Rht-B1c Della mutant of wheat (Triticum aestivum L.) led to the isolation of overgrowth mutants, which retained the original dwarfing gene but grew at a faster rate because of a new mutation elsewhere in that gene. Forty-six alleles were identified, which included amino acid substitutions, premature stop codons, and splice site alterations. The sites of amino acid substitution were primarily localised around conserved motifs in the DELLA protein, and these mutants showed a wide range in their extent of growth recovery (dwarf, semidwarf, tall). Detailed growth comparisons were made on a wide height range of backcrossed overgrowth alleles, comparing stem and spike growth, leaf size, tillering, phenological development, coleoptile length, grain dormancy and grain yield. There were large and reproducible differences between alleles for some traits, whereas others were largely unaffected or varied with growth conditions. Some of the overgrowth alleles offer promise as alternatives to the Rht-B1b and Rht-D1b dwarfing genes, allowing a wider range of height control, improved grain dormancy and equivalent grain yield. The collection of mutants will also be valuable as a resource to study the effect of height on different physiological or agronomic traits, and in elucidating DELLA protein function.
利用小麦（Triticum aestivum L.）的矮化Rht-B1c Della突变体进行的抑制子筛选，分离出了过度生长突变体，这些突变体保留了原始的矮化基因，但由于该基因其他位置的新突变而生长速度加快。鉴定出了46个等位基因，包括氨基酸替换、提前终止密码子和剪接位点改变。氨基酸替换位点主要定位在DELLA蛋白的保守基序周围，这些突变体在生长恢复程度上表现出很大差异（矮化、半矮化、高杆）。对一系列回交过度生长等位基因在广泛的高度范围内进行了详细的生长比较，比较了茎和穗的生长、叶片大小、分蘖、物候发育、胚芽鞘长度、种子休眠和籽粒产量。某些性状的等位基因之间存在巨大且可重复的差异，而其他性状在很大程度上不受影响或随生长条件而变化。一些过度生长等位基因有望作为Rht-B1b和Rht-D1b矮化基因的替代物，实现更广泛的株高控制、改善种子休眠并保持相当的籽粒产量。这些突变体的集合作为研究株高对不同生理或农艺性状的影响以及阐明DELLA蛋白功能的资源也将具有重要价值。
