Masoomi-Aladizgeh Farhad, Aalami Ali, Esfahani Masoud, Aghaei Mohamad Jaafar, Mozaffari Khadijeh
Department of Agronomy and Plant Breeding, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran.
Appl Biochem Biotechnol. 2015 Jun;176(4):1059-70. doi: 10.1007/s12010-015-1629-8. Epub 2015 Apr 22.
Low temperature as one of the most important environmental factors limits the productivity of plants across the world. Aegilops, as a wild species of Poaceae, contains low temperature-responsive genes. In this study, we analyzed morphological (wilting, chlorosis, and recovery) and physiological (ion leakage) characteristics to identification of a cold-tolerant genotype. In this experiment, we introduced two transcription factors (TFs) in Aegilops species for the first time. Bioinformatics analysis demonstrated that our nucleotide sequences have high similarity with CBF14 (C-repeat-binding factor) and NAC2 (NAM, ATAF, and CUC) in Triticum aestivum. Based on the physiological and morphological data, one genotype (Aladizgeh) was identified as the most resistant genotype which was selected for further gene expression analysis. The real-time PCR results indicated that the CBF14 gene was not expressed 3 h following cold treatment, but the highest expression was observed after 6, 12, and 24 h of cold treatment; however, a sudden decrease was observed in its expression after 30 h. The NAC2 gene also was not expressed 3 h after cold stress, but the highest expression was at 24 h and similar to the CBF14 gene; its expression suddenly decreased after 30 h. Our results indicated that this genotype can tolerate -4 °C for 3 h, but the CBF14 and NAC2 genes were activated when treated for longer durations. Expression of TFs studied in this experiment had decreased after 30 h, in which cell death seems to be the important reason.
低温作为最重要的环境因素之一，限制了全球植物的生产力。山羊草作为禾本科的一个野生种，含有低温响应基因。在本研究中，我们分析了形态学（萎蔫、黄化和恢复）和生理学（离子渗漏）特征以鉴定耐寒基因型。在本实验中，我们首次在山羊草物种中引入了两个转录因子（TFs）。生物信息学分析表明，我们的核苷酸序列与普通小麦中的CBF14（C-重复结合因子）和NAC2（NAM、ATAF和CUC）具有高度相似性。基于生理和形态学数据，一种基因型（Aladizgeh）被鉴定为最抗性的基因型，并被选用于进一步的基因表达分析。实时PCR结果表明，CBF14基因在冷处理3小时后未表达，但在冷处理6、12和24小时后观察到最高表达；然而，在30小时后其表达突然下降。NAC2基因在冷胁迫3小时后也未表达，但在24小时时表达最高，与CBF14基因相似；其表达在30小时后突然下降。我们的结果表明，该基因型可以耐受-4°C 3小时，但在处理更长时间时CBF14和NAC2基因被激活。本实验中研究的转录因子的表达在30小时后下降，其中细胞死亡似乎是重要原因。
