Zhao Bo, Li Haitao, Li Juanjuan, Wang Bo, Dai Cheng, Wang Jing, Liu Kede
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China.
Theor Appl Genet. 2017 Apr;130(4):727-741. doi: 10.1007/s00122-016-2846-4. Epub 2017 Jan 16.
Identification and characterization of a semi-dwarfing gene ds-3 encoding a mutant DELLA protein regulating plant height through gibberellin signaling pathway. Lodging is one of the most important factors causing severe yield loss in oilseed rape. Utilization of semi-dwarf varieties has been proved the most effective way to increase lodging resistance and yield in many crops. To develop semi-dwarf germplasm in oilseed rape, we identified a semi-dwarf mutant ds-3 which showed a reduced response to phytohormones gibberellins (GAs). Genetic analysis indicated the dwarfism was controlled by a single semi-dominant gene, ds-3. The DS-3 gene was mapped to a genomic region on chromosome C07, which is syntenic to the region of a previously identified semi-dwarf gene ds-1 (BnaA06.RGA). In this region, DS-3 (BnaC07.RGA) gene was identified to encode a DELLA protein that functions as a repressor in GA signaling pathway. A substitution of proline to leucine was identified in ds-3 in the conserved VHYNP motif, which is essential for GA-dependent interaction between gibberellin receptor GID1 and DELLA proteins. Segregation analysis in the F population derived from the cross between ds-1 and ds-3 demonstrated that BnaA06.RGA displayed a stronger effect on plant height than BnaC07.RGA, indicating that different RGA genes may play different roles in stem elongation. In addition to BnaA06.RGA and BnaC07.RGA, two more RGA genes (BnaA09.RGA and BnaC09.RGA) were identified in the Brassica napus (B. napus) genome. Reverse-transcription polymerase chain reaction (RT-PCR) and yeast two-hybrid (Y2H) assays suggest that both BnaA09.RGA and BnaC09.RGA are transcribed in leaves and stems and can mediate GA signaling in vivo. These genes represent potential targets for screening ideal semi-dwarfing alleles for oilseed rape breeding.
一个编码突变DELLA蛋白的半矮化基因ds-3的鉴定与表征，该蛋白通过赤霉素信号通路调控株高。倒伏是导致油菜籽严重减产的最重要因素之一。在许多作物中，利用半矮化品种已被证明是提高抗倒伏能力和产量的最有效方法。为了培育油菜的半矮化种质，我们鉴定了一个半矮化突变体ds-3，它对植物激素赤霉素（GA）的反应减弱。遗传分析表明，矮化性状由一个单基因ds-3控制，呈半显性遗传。DS-3基因被定位到C07染色体上的一个基因组区域，该区域与之前鉴定的半矮化基因ds-1（BnaA06.RGA）所在区域同源。在该区域，DS-3（BnaC07.RGA）基因被鉴定为编码一种DELLA蛋白，该蛋白在GA信号通路中起阻遏作用。在ds-3的保守VHYNP基序中发现脯氨酸被亮氨酸取代，该基序对于赤霉素受体GID1与DELLA蛋白之间的GA依赖性相互作用至关重要。对ds-1和ds-3杂交产生的F群体进行的分离分析表明，BnaA06.RGA对株高的影响比BnaC07.RGA更强，这表明不同的RGA基因在茎伸长过程中可能发挥不同的作用。除了BnaA06.RGA和BnaC07.RGA外，在甘蓝型油菜（B. napus）基因组中还鉴定出另外两个RGA基因（BnaA09.RGA和BnaC09.RGA）。逆转录聚合酶链反应（RT-PCR）和酵母双杂交（Y2H）分析表明，BnaA09.RGA和BnaC09.RGA在叶片和茎中均有转录，并且可以在体内介导GA信号传导。这些基因是油菜育种中筛选理想半矮化等位基因的潜在靶点。
