Jang Geupil, Lee Jung-Hun, Rastogi Khushboo, Park Suhyoung, Oh Sang-Hun, Lee Ji-Young
School of Biological Sciences, College of Natural Science, Seoul National University, Seoul 151-747, Korea.
Department of Horticultural Crop Research, National Institute of Horticultural and Herbal Science, Wanju 565-852, Korea.
J Exp Bot. 2015 Aug;66(15):4607-19. doi: 10.1093/jxb/erv220. Epub 2015 May 15.
The root serves as an essential organ in plant growth by taking up nutrients and water from the soil and supporting the rest of the plant body. Some plant species utilize roots as storage organs. Sweet potatoes (Ipomoea batatas), cassava (Manihot esculenta), and radish (Raphanus sativus), for example, are important root crops. However, how their root growth is regulated remains unknown. In this study, we characterized the relationship between cambium and radial root growth in radish. Through a comparative analysis with Arabidopsis root expression data, we identified putative cambium-enriched transcription factors in radish and analysed their expression in representative inbred lines featuring distinctive radial growth. We found that cell proliferation activities in the cambium positively correlated with radial growth and final yields of radish roots. Expression analysis of candidate transcription factor genes revealed that some genes are differentially expressed between inbred lines and that the difference is due to the distinct cytokinin response. Taken together, we have demonstrated for the first time, to the best of our knowledge, that cytokinin-dependent radial growth plays a key role in the yields of root crops.
根是植物生长中的重要器官，它从土壤中吸收养分和水分，并支撑植物的其他部分。一些植物物种利用根作为储存器官。例如，红薯（甘薯）、木薯（木薯）和萝卜（萝卜）都是重要的块根作物。然而，它们的根生长是如何调节的仍然未知。在这项研究中，我们表征了萝卜形成层与根径向生长之间的关系。通过与拟南芥根表达数据的比较分析，我们在萝卜中鉴定出了假定的富含形成层的转录因子，并分析了它们在具有独特径向生长的代表性自交系中的表达。我们发现，形成层中的细胞增殖活动与萝卜根的径向生长和最终产量呈正相关。候选转录因子基因的表达分析表明，一些基因在自交系之间存在差异表达，且这种差异是由于细胞分裂素反应不同所致。据我们所知，我们首次证明了细胞分裂素依赖性径向生长在块根作物产量中起关键作用。
