Department of Plant Science, Seoul National University, Seoul 08826, Korea.
Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea.
Genes (Basel). 2020 Jun 1;11(6):611. doi: 10.3390/genes11060611.
We analyzed the transcriptomes in the shoots of five-year-old 'Soomee' peach trees () during cold acclimation (CA), from early CA (end of October) to late CA (middle of January), and deacclimation (DA), from late CA to late DA (middle of March), to identify the genes involved in cold hardiness. Cold hardiness of the shoots increased from early to late CA, but decreased from late CA to late DA, as indicated by decreased and increased the median lethal temperature (LT), respectively. Transcriptome analysis identified 17,208 assembled transcripts during all three stages. In total, 1891 and 3008 transcripts were differentially expressed with a |fold change| > 2 ( < 0.05) between early and late CA, and between late CA and late DA, respectively. Among them, 1522 and 2830, respectively, were functionally annotated with gene ontology (GO) terms having a greater proportion of differentially expressed genes (DEGs) associated with molecular function than biological process or cellular component categories. The biochemical pathways best represented both periods from early to late CA and from late CA to late DA were 'metabolic pathway' and 'biosynthesis of secondary metabolites'. We validated these transcriptomic results by performing reverse transcription quantitative polymerase chain reaction on the selected DEGs showing significant fold changes. The relative expressions of the selected DEGs were closely related to the LT values of the peach tree shoots: 'Soomee' shoots exhibited higher relative expressions of the selected DEGs than shoots of the less cold-hardy 'Odoroki' peach trees. Irrespective of the cultivar, the relative expressions of the DEGs that were up- and then down-regulated during CA, from early to late CA, and DA, from late CA to late DA, were more closely correlated with cold hardiness than those of the DEGs that were down- and then up-regulated. Therefore, our results suggest that the significantly up- and then down-regulated DEGs are associated with cold hardiness in peach tree shoots. These DEGs, including , , , , and could be candidate genes to determine cold hardiness.
我们分析了五年生‘Soomee’桃树在冷驯化（CA）过程中茎的转录组，从早期 CA（10 月底）到晚期 CA（1 月初），以及脱驯化（DA），从晚期 CA 到晚期 DA（3 月中旬），以鉴定与抗寒性相关的基因。随着中位致死温度（LT）的降低和升高，分别从早期 CA 到晚期 CA 和从晚期 CA 到晚期 DA 时，枝条的抗寒性增加和减少。转录组分析在所有三个阶段鉴定了 17208 个组装转录本。在早期 CA 和晚期 CA 之间以及晚期 CA 和晚期 DA 之间的差异表达基因（DEG）的 |fold change| > 2（ < 0.05）的转录本分别为 1891 个和 3008 个。其中，分别有 1522 个和 2830 个转录本具有基因本体（GO）术语的功能注释，这些术语具有与分子功能相关的更大比例的 DEG，而不是与生物过程或细胞成分类别相关的 DEG。在从早期 CA 到晚期 CA 和从晚期 CA 到晚期 DA 的两个时期中，最佳代表生化途径的是“代谢途径”和“次生代谢物的生物合成”。我们通过对具有显著折叠变化的选定 DEG 进行逆转录定量聚合酶链反应来验证这些转录组结果。所选 DEG 的相对表达与桃树枝条的 LT 值密切相关：‘Soomee’枝条表现出比耐寒性较差的‘Odoroki’桃树枝条更高的所选 DEG 的相对表达。无论品种如何，在 CA 过程中从早期 CA 到晚期 CA 以及在 DA 过程中从晚期 CA 到晚期 DA 中上调然后下调的 DEG 的相对表达与冷驯化的关系更为密切，而在 CA 过程中下调然后上调的 DEG 的相对表达则不那么密切。因此，我们的结果表明，显著上调然后下调的 DEG 与桃树枝条的抗寒性有关。这些 DEG，包括 、 、 、 和 ，可能是决定桃树抗寒性的候选基因。
