Wang Y-P, Tang S-Q, Chen H-Z, Wu Z-F, Zhang H, Duan E-C, Shi Q-H, Wu Z-M
Key Laboratory of Crop Physiology, Ecology and Genetic Breeding of Jiangxi Province, Jiangxi Agricultural University, Nanchang, China.
Pingxiang Municipal Institute of Agricultural Science, Pingxiang, China.
Plant Biol (Stuttg). 2017 Nov;19(6):851-858. doi: 10.1111/plb.12612. Epub 2017 Sep 5.
Metabolism of strigolactones (SLs) can improve the efficiency of nutrient use by regulating the development of roots and shoots in crops, making them an important research focus for molecular breeding. However, as a very important plant hormone, the molecular mechanism of SL signal transduction still remains largely unknown. In this study, we isolated an indica high-tillering dwarf mutant 4 (htd4), a spontaneous mutant of rice, from the restorer line Gui99. Mapping and sequencing analysis showed that htd4 was a novel allelic mutant of D14, in which a single base substitution forms a premature termination codon. Quantitative RT-PCR analyses revealed that expression levels of the genes D10, D17, D27, D3 and D14 increased significantly, while expression of D53 decreased in htd4, compared with the wild type. A subcellular localisation assay showed that the mutant of D14 in htd4 did not disturb the normal localisation of D14 proteins. However, a BiFC assay suggested that the mutant-type D14 could not interact with D3. Additionally, compared with other D14 allelic mutants, htd4 was the first mutant of D14 discovered in indica, and the differences in many yield traits such as plant height, seed-setting rate and grain sizes between htd4 and the wild type were less than those between other D14 allelic mutants and the wild type. Therefore, htd4 is considered a mild phenotype allelic mutant of D14. We conclude that the absence of functional D14 caused the high-tillering dwarf phenotype of htd4. Our results may provide vital information for research on D14 function and the application of htd4 in molecular breeding.
独脚金内酯（SLs）的代谢可通过调节作物根和地上部的发育来提高养分利用效率，使其成为分子育种的重要研究热点。然而，作为一种非常重要的植物激素，SL信号转导的分子机制仍 largely未知。在本研究中，我们从恢复系桂99中分离出一个籼型高蘖矮化突变体4（htd4），它是水稻的一个自发突变体。定位和测序分析表明，htd4是D14的一个新的等位突变体，其中单个碱基替换形成了一个提前终止密码子。定量RT-PCR分析显示，与野生型相比，htd4中基因D10、D17、D27、D3和D14的表达水平显著增加，而D53的表达降低。亚细胞定位分析表明，htd4中D14的突变体不干扰D14蛋白的正常定位。然而，双分子荧光互补（BiFC）分析表明，突变型D14不能与D3相互作用。此外，与其他D14等位突变体相比，htd4是在籼稻中发现的第一个D14突变体，htd4与野生型之间在株高、结实率和粒型等许多产量性状上的差异小于其他D14等位突变体与野生型之间的差异。因此，htd4被认为是D14的一个温和表型等位突变体。我们得出结论，功能性D14的缺失导致了htd4的高蘖矮化表型。我们的结果可能为D14功能研究以及htd4在分子育种中的应用提供重要信息。
