College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.
BMC Plant Biol. 2018 Sep 4;18(1):178. doi: 10.1186/s12870-018-1400-8.
Chrysanthemum is among the top ten traditional flowers in China, and one of the four major cut flowers in the world, but the growth of chrysanthemum is severely restricted by high temperatures which retard growth and cause defects in flowers. DREB (dehydration-responsive element-binding) transcription factors play important roles in the response to abiotic and biotic stresses. However, whether the DREB A-6 subgroup is involved in heat tolerance has not been reported conclusively.
In the present study, CmDREB6 was cloned from chrysanthemum (Chrysanthemum morifolium) 'Jinba'. CmDREB6, containing a typical AP2/ERF domain, was classed into the DREB A-6 subgroup and shared highest homology with Cichorium intybus L. CiDREB6 (73%). CmDREB6 was expressed at its highest levels in the leaf. The CmDREB6 protein localized to the nucleus. Based on the yeast one hybrid assay, CmDREB6 showed transcription activation activity in yeast, and the transcriptional activation domain was located in the 3 'end ranging from 230 to 289 amino acids residues. CmDREB6 overexpression enhanced the tolerance of chrysanthemum to heat. The survival rate of two transgenic lines was as high as 85%, 50%, respectively, in contrast to 3.8% of wild-type (WT). Over-expression of CmDREB6 promoted the expression of CmHsfA4, CmHSP90, and the active oxygen scavenging genes CmSOD and CmCAT.
In this study, DREB A-6 subgroup gene CmDREB6 was cloned from chrysanthemum 'Jinba'. Overexpression of CmDREB6 enhanced heat tolerance of chrysanthemum by regulating genes involved in the heat shock response and ROS homeogenesis.
菊花是中国十大传统名花之一，也是世界四大切花之一，但菊花的生长受到高温的严重限制，高温会减缓生长速度并导致花朵畸形。DREB（脱水应答元件结合）转录因子在应对非生物和生物胁迫方面发挥着重要作用。然而，DREB A-6 亚组是否参与耐热性尚未得到明确报道。
本研究从菊花（Chrysanthemum morifolium）‘Jinba’中克隆了 CmDREB6。CmDREB6 含有一个典型的 AP2/ERF 结构域，被归类为 DREB A-6 亚组，与菊苣 L. CiDREB6（73%）具有最高的同源性。CmDREB6 在叶片中表达水平最高。CmDREB6 蛋白定位于细胞核内。基于酵母单杂交试验，CmDREB6 在酵母中显示出转录激活活性，转录激活结构域位于 3'端 230 至 289 个氨基酸残基范围内。CmDREB6 的过表达增强了菊花对热的耐受性。两个转基因株系的存活率分别高达 85%和 50%，而野生型（WT）的存活率仅为 3.8%。CmDREB6 的过表达促进了 CmHsfA4、CmHSP90 和活性氧清除基因 CmSOD 和 CmCAT 的表达。
本研究从菊花‘Jinba’中克隆了 DREB A-6 亚组基因 CmDREB6。过表达 CmDREB6 通过调节参与热激反应和 ROS 发生的基因增强了菊花的耐热性。
