李欢倪+仇静静+马俊杰+李长生+侯蕾

摘要：本研究利用快中子辐照花生山花13号的干种子，获得了一个性状稳定遗传的花生半矮化突变体sdm1（semi-dwarf mutant 1），继而对其矮化形态、经济性状指标及赤霉素响应特性进行了分析。结果表明，与山花13号相比，该突变体植株半矮化、枝较粗，种仁较大、种皮色泽较深，种子成分中含油量提高、粗蛋白含量下降。采用酶联免疫吸附法（ELISA）测定了突变体叶片中赤霉素的含量，发现突变体赤霉素含量明显低于山花13號，用 GA3处理突变体能够恢复突变体的株高。利用qRT-PCR方法分析赤霉素代谢和信号传导途径相关基因的转录水平，发现AhGA2ox、AhGA3ox、AhGA20ox、AhDella2、AhDella3等基因的表达均发生明显变化。以上结果表明，突变体内赤霉素合成途径关键酶基因的表达水平发生变化，使赤霉素合成能力下降，导致植株内赤霉素水平降低，从而出现矮化表型。

关键词：花生；半矮化；突变体；赤霉素；基因表达

中图分类号：S565.2文献标识号：A文章编号：1001-4942（2017）12-0001-05

Abstract One semi-dwarf mutant sdm1 with stable inheritance was isolated from peanut cultivar Shanhua 13 induced by fast neutron irradiation. Its dwarf morphology， economic traits and response to gibberellin were analyzed. The results showed that compared with Shanhua 13， sdm1 showed semi-dwarf in plant height， thicker branches， larger seeds and darker seed coat color. The seed oil content of the mutant was increased and the protein content was decreased. The GA3 content in the leaves of sdm1 mutant was determined using enzyme-linked immunosorbent assay （ELISA）， and we found that its gibberellin content was significantly lower than that in Shanhua 13. Treated with exogenous GA3 could restore the dwarf phenotype of mutant. The qRT-PCR was used to analyze the transcriptional level of genes related to GA biosynthesis pathway and signal transduction pathway， and the results showed that the expression level of AhGA2ox， AhGA3ox， AhGA20ox， AhDella2 and AhDella3 changed significantly. The changed expression of these key enzyme genes led to the decrease of gibberellin content in mutant plants and caused dwarf phenotype.

Keywords Peanut； Semi-dwarf； Mutant； Gibberellins； Gene expression

矮化突变体是改善作物株型、培育抗倒高产新品种的基础，也是鉴定植物矮化基因、研究株型调控分子机理的重要材料。然而，极端矮化往往会导致植物生物量下降，产量降低；而半矮化是一种优良的农艺性状，可在保证产量的前提下改善植物株型，减少生产过程中的化控，降低药剂使用对环境的污染，同时也减少了人工成本。创建优良株型，可通过改善种植密度使个体和群体协调发展，提高光能和土地资源利用率，从而提高作物产量[1]。……