Much effort has been made on the dissection of cold response in citrus, but relevant study in wild germplasm has been rare. Based on the result of the membership function value analysis with 12 physiological indexes, we reported a wild citrus germplasm, Chongyi wild mandarin (Citrus reticulata), which was more cold-tolerant than a cold-hardy rootstock, Poncirus trifoliata. To gain an overview of transcriptome changes under cold, leaves of Chongyi wild mandarin were sampled at 0, 1, 5 d after 0 °C treatment, and sequenced using an Illumina sequencing platform. Totally, 3921 and 5995 differentially expressed genes (DEGs) were identified in 1 d and 5 d, respectively. And then, RNA-seq results were further validated via real-time quantitative PCR with 17 DEGs. Many DEGs related to various cold signaling pathways were identified, especially those related to brassinosteroid cascade. Around 10 % of the total DEGs were transcription factors from 67 families, suggesting that transcriptional regulation, both C-repeat/dehydration responsive element-binding factor-dependent/independent pathways, was crucial for the cold tolerance of Chongyi wild mandarin. Our data also revealed that the transcriptional levels of many DEGs related to anti-oxidant enzymes and osmoprotectants metabolism were altered, which were consistent with the results of physiological experiments. Moreover, a number of DEGs involved in ABA, BR, GA metabolisms were isolated. Accordingly, the levels of ABA and BR were significantly increased under cold, but GAs were decreased. Taken together, this work provided a comprehensive view of physiological and transcriptional alterations in cold response of Chongyi wild mandarin.

在剖析柑桔中的冷反应方面已经做出了很多努力，但是有关野生种质的相关研究却很少。基于12个生理指标的隶属函数值分析结果，我们报告了一种野生柑橘种质，崇义野生普通话（Citrus reticulata），其耐寒性比耐寒的砧木Poncirus trifoliata。为了全面了解寒冷条件下的转录组变化，在0°C处理后的0、1、5 d对崇义野生普通话的叶子进行了采样，并使用Illumina测序平台进行了测序。总共分别在1 d和5 d内鉴定了3921和5995个差异表达基因（DEG）。然后，通过17个DEG的实时定量PCR进一步验证了RNA-seq的结果。确定了许多与各种冷信号通路相关的DEG，尤其是与油菜素甾体级联反应相关的DEG。总DEG中约有10％是来自67个科的转录因子，这表明C-重复/脱水反应元件结合因子依赖性/非依赖性途径的转录调控对崇义野生普通话的耐寒性至关重要。我们的数据还显示，与抗氧化酶和渗透保护剂代谢有关的许多DEG的转录水平发生了变化，这与生理学实验的结果一致。此外，分离了许多涉及ABA，BR，GA代谢的DEG。因此，低温下ABA和BR的含量显着增加，而GAs降低。两者合计，这项工作提供了崇义野生普通话寒冷反应的生理和转录变化的全面视图。但GA减少了。两者合计，这项工作提供了崇义野生普通话寒冷反应的生理和转录变化的全面视图。但GA减少了。两者合计，这项工作提供了崇义野生普通话寒冷反应的生理和转录变化的全面视图。