Forest Tree Breeding Center, Forestry and Forest Products Research Institute, Forest Research and Management Organization, Hitachi, Ibaraki, Japan.
Department of Forest Environmental Sciences, Faculty of Agriculture, Kyushu University, Fukuoka, Japan.
PLoS One. 2020 Mar 9;15(3):e0229843. doi: 10.1371/journal.pone.0229843. eCollection 2020.
Seasonal phenomena in plants are primarily affected by day length and temperature. The shoot transcriptomes of trees grown in the field and a controlled-environment chamber were compared to characterize genes that control annual rhythms and the effects of day length- and temperature-regulated genes in the gymnosperm Japanese cedar (Cryptomeria japonica D. Don), which exhibits seasonally indeterminate growth. Annual transcriptome dynamics were clearly demonstrated by principal component analysis using microarray data obtained under field-grown conditions. Analysis of microarray data from trees grown in a controlled chamber identified 2,314 targets exhibiting significantly different expression patterns under short-day (SD) and long-day conditions, and 2,045 targets exhibited significantly different expression patterns at 15°C (LT; low temperature) versus 25°C. Interestingly, although growth was suppressed under both SD and LT conditions, approximately 80% of the SD- and LT-regulated targets differed, suggesting that each factor plays a unique role in the annual cycle. The top 1,000 up-regulated targets in the growth/dormant period in the field coincided with more than 50% of the SD- and LT-regulated targets, and gene co-expression network analysis of the annual transcriptome indicated a close relationship between the SD- and LT-regulated targets. These results indicate that the respective effects of day length and temperature interact to control annual transcriptome dynamics. Well-known upstream genes of signaling pathways responsive to environmental conditions, such as the core clock (LHY/CjLHYb and CCA1/CjLHYa) and PEBP family (MFT) genes, exhibited unique expression patterns in Japanese cedar compared with previous reports in other species, suggesting that these genes control differences in seasonal regulation mechanisms between species. The results of this study provide new insights into seasonal regulation of transcription in Japanese cedar.
植物的季节性现象主要受日照长度和温度的影响。将在田间和人工气候室中生长的树木的芽转录组进行比较，以鉴定控制年度节律的基因，并研究调控针叶树日本雪松（Cryptomeria japonica D. Don）的基因，日本雪松表现出季节性不定生长。通过在田间条件下获得的微阵列数据的主成分分析，清楚地显示了年度转录组动态。在人工气候室中生长的树木的微阵列数据分析确定了 2314 个目标，在短日照（SD）和长日照条件下表现出明显不同的表达模式，在 15°C（LT；低温）和 25°C 下表现出明显不同的表达模式。有趣的是，尽管在 SD 和 LT 条件下生长受到抑制，但约 80%的 SD 和 LT 调控的目标不同，这表明每个因素在年度周期中发挥独特的作用。在田间生长/休眠期上调的前 1000 个目标与 SD 和 LT 调控的目标中的 50%以上重叠，年度转录组的基因共表达网络分析表明 SD 和 LT 调控的目标之间存在密切关系。这些结果表明，日照长度和温度的各自影响相互作用，共同控制年度转录组动态。对环境条件有反应的信号通路的上游基因，如核心时钟（LHY/CjLHYb 和 CCA1/CjLHYa）和 PEBP 家族（MFT）基因，与其他物种的先前报道相比，在日本雪松中表现出独特的表达模式，这表明这些基因控制了物种间季节性调节机制的差异。本研究结果为日本雪松转录季节性调节提供了新的见解。
