Byun Mi Young, Cui Li Hua, Lee Jungeun, Park Hyun, Lee Andosung, Kim Woo Taek, Lee Hyoungseok
Unit of Polar Genomics, Korea Polar Research Institute, Incheon, South Korea.
Department of Systems Biology, Yonsei University, Seoul, South Korea.
Front Plant Sci. 2018 May 3;9:601. doi: 10.3389/fpls.2018.00601. eCollection 2018.
Few plant species can survive in Antarctica, the harshest environment for living organisms. is the only natural grass species to have adapted to and colonized the maritime Antarctic. To investigate the molecular mechanism of the Antarctic adaptation of this plant, we identified and characterized (), which belongs to monocot CBF group IV. The transcript level of in was markedly increased by cold and dehydration stress. To assess the roles of in plants, we generated a -overexpressing transgenic rice plant () and analyzed its abiotic stress response phenotype. displayed enhanced tolerance to cold stress without growth retardation under any condition compared to wild-type plants. Because the cold-specific phenotype of was similar to that of (Byun et al., 2015), we screened for the genes responsible for the improved cold tolerance in rice by selecting differentially regulated genes in both transgenic rice lines. By comparative transcriptome analysis using RNA-seq, we identified 9 and 15 genes under normal and cold-stress conditions, respectively, as putative downstream targets of the two CBFs. Overall, our results suggest that Antarctic hairgrass mediates the cold-stress response of transgenic rice plants by adjusting the expression levels of a set of stress-responsive genes in transgenic rice plants. Moreover, selected downstream target genes will be useful for genetic engineering to enhance the cold tolerance of cereal plants, including rice.
很少有植物物种能在南极洲生存，那里是最恶劣的生物生存环境。南极发草是唯一一种适应并在南极海洋地区定殖的天然禾本科物种。为了研究这种植物适应南极环境的分子机制，我们鉴定并表征了属于单子叶植物CBF第四组的DcCBF4。在南极发草中，DcCBF4的转录水平在低温和脱水胁迫下显著增加。为了评估DcCBF4在植物中的作用，我们构建了过表达DcCBF4的转基因水稻植株（DcCBF4-OE），并分析了其非生物胁迫响应表型。与野生型植株相比，DcCBF4-OE在任何条件下对低温胁迫均表现出增强的耐受性且无生长迟缓现象。由于DcCBF4-OE的低温特异性表型与OsCBF4-OE相似（Byun等人，2015年），我们通过选择两个转基因水稻品系中差异表达的基因，筛选出了负责水稻耐寒性提高的基因。通过使用RNA测序进行比较转录组分析，我们分别在正常和低温胁迫条件下鉴定出9个和15个基因，作为两个DcCBF的假定下游靶标。总体而言，我们的结果表明，南极发草通过调节转基因水稻植株中一组胁迫响应基因的表达水平，介导了转基因水稻植株的低温胁迫响应。此外，所选的下游靶标基因将有助于通过基因工程提高包括水稻在内的谷类植物的耐寒性。
