The AP2/ERF (APETALA2/ethylene-responsive factor) family of transcription factors (TF) is involved in regulating biotic and abiotic stress responses in plants. To explore the role of AP2/ERFs in cold tolerance in woody plants, BpERF13 was cloned and characterized in Betula platyphylla (white birch), a species primarily found in Asia in temperate and boreal climates. Based on phylogenetic analysis, BpERF13 is a member of the IXb subfamily of ERFs. Using qRT-PCR, we found that BpERF13 was differentially expressed in different tissues, and its expression could be induced by cold treatment (4 °C). BpERF13 protein, fused with GFP, was exclusively localized to nuclei. To further assess the role of BpERF13 in cold tolerance, BpERF13 overexpression (OE) transgenic lines were generated in B. platyphylla and used for cold stress treatment and biochemical/physiological studies. BpERF13 overexpression lines had significantly increased tolerance to subfreezing treatment and reduced reactive oxygen species. Using a TF-centered yeast one-hybrid (Y1H) experimental system, we showed that BpERF13 could bind to LTRECOREATCOR15 and MYBCORE cis-elements to activate a reporter gene. ChIP-seq and ChIP-PCR experiments further demonstrated that BpERF13 bound to these cis-elements when present in the 5' proximal regions of superoxide dismutase (SOD), peroxidase (POD), and C-repeat-binding factor (CBF) genes. qRT-PCR was employed to examine the expression levels of these genes in response to cold stress; SOD, POD, and CBF genes were significantly upregulated in BpERF13 transgenic lines compared to wild-type plants in response to cold stress. These results indicate that the transcription factor BpERF13 regulates physiological processes underlying cold tolerance in woody plants.

中文翻译：

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桦木中 AP2/ERF 家族基因 BpERF13 的过表达通过上调 CBF 基因和减少活性氧来增强耐寒性

AP2/ERF（APETALA2/乙烯反应因子）家族的转录因子（TF）参与调节植物的生物和非生物胁迫反应。为了探索 AP2/ERFs 在木本植物耐寒性中的作用，BpERF13 在白桦（白桦）中被克隆和表征，白桦是一种主要在亚洲温带和北方气候中发现的物种。根据系统发育分析，BpERF13 是 ERF IXb 亚家族的成员。使用qRT-PCR，我们发现BpERF13在不同组织中的表达存在差异，冷处理（4°C）可以诱导其表达。与 GFP 融合的 BpERF13 蛋白仅定位于细胞核。为了进一步评估 BpERF13 在耐寒中的作用，在 B. platyphylla，用于冷应激处理和生化/生理研究。BpERF13 过表达系对低温处理的耐受性显着增加，活性氧种类减少。使用以 TF 为中心的酵母单杂交 (Y1H) 实验系统，我们表明 BpERF13 可以与 LTRECOREATCOR15 和 MYBCORE 顺式元件结合以激活报告基因。ChIP-seq 和 ChIP-PCR 实验进一步证明，当 BpERF13 存在于超氧化物歧化酶 (SOD)、过氧化物酶 (POD) 和 C-重复结合因子 (CBF) 基因的 5' 近端区域时，BpERF13 与这些顺式元件结合。qRT-PCR 被用来检测这些基因在冷胁迫下的表达水平；与野生型植物相比，响应冷胁迫的 SOD、POD 和 CBF 基因在 BpERF13 转基因品系中显着上调。