State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Engineering Research Center for Grassland Science, College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China.
College of Grassland Science, Nanjing Agricultural University, Nanjing, 210095, China.
Plant Cell Environ. 2018 Sep;41(9):2021-2032. doi: 10.1111/pce.13114. Epub 2018 Jan 10.
Ethylene responsive factor (ERF) subfamily transcription factors play an important role in plant abiotic and biotic stress tolerance. A cold responsive ERF, MfERF1, was isolated from Medicago falcata, an important forage legume that has great cold tolerance. Overexpression of MfERF1 resulted in an increased tolerance to freezing and chilling in transgenic tobacco plants, whereas down-regulation of the ortholog of MfERF1 in Medicago truncatula resulted in reduced freezing tolerance in RNAi plants. Higher transcript levels of some stress responsive genes (CHN50, OSM, ERD10C, and SAMS) and those involved in spermidine (Spd) and spermine (Spm) synthesis (SAMDC1, SAMDC2, SPDS1, SPDS2, and SPMS) and catabolism (PAO) were observed in transgenic plants than in wild type. However, neither Spd nor Spm level was accumulated in transgenic plants as a result of promoted polyamine oxidase activity. Transgenic plants had higher activities of antioxidants associated with the induced encoding genes including Cu, Zn-SOD, CAT1, CAT2, CAT3, and cpAPX and accumulated more proline associated with induced P5CS and reduced PROX2 transcription as compared with wild type. The results suggest that MfERF1 confers cold tolerance through promoted polyamine turnover, antioxidant protection, and proline accumulation.
乙烯响应因子（ERF）亚家族转录因子在植物非生物和生物胁迫耐受中发挥重要作用。从紫花苜蓿中分离出一个冷响应 ERF，MfERF1，它是一种重要的耐冷豆科牧草。在转基因烟草植物中过表达 MfERF1 导致对冷冻和冷藏的耐受性增加，而在 Medicago truncatula 中下调 MfERF1 的同源物导致 RNAi 植物的冷冻耐受性降低。一些应激响应基因（CHN50、OSM、ERD10C 和 SAMS）和那些参与腐胺（Spd）和精胺（Spm）合成（SAMDC1、SAMDC2、SPDS1、SPDS2 和 SPMS）和分解代谢（PAO）的基因在转基因植物中转录水平较高，高于野生型。然而，由于促进多胺氧化酶活性，转基因植物中既没有积累 Spd 也没有积累 Spm。与野生型相比，转基因植物具有更高的与诱导编码基因相关的抗氧化剂活性，包括 Cu、Zn-SOD、CAT1、CAT2、CAT3 和 cpAPX，并且与诱导的 P5CS 相关的脯氨酸积累更多，而 PROX2 转录减少。结果表明，MfERF1 通过促进多胺周转、抗氧化保护和脯氨酸积累赋予植物耐寒性。
