• Plants are continuously exposed to diurnal fluctuations in light and temperature, and spontaneous changes in their physical or biotic environment. The circadian clock coordinates regulation of gene expression with a 24 h period, enabling the anticipation of these events.
• We used RNA sequencing to characterize the Brachypodium distachyon transcriptome under light and temperature cycles, as well as under constant conditions.
• Approximately 3% of the transcriptome was regulated by the circadian clock, a smaller proportion than reported in most other species. For most transcripts that were rhythmic under all conditions, including many known clock genes, the period of gene expression lengthened from 24 to 27 h in the absence of external cues. To functionally characterize the cyclic transcriptome in B. distachyon, we used Gene Ontology enrichment analysis, and found several terms significantly associated with peak expression at particular times of the day. Furthermore, we identified sequence motifs enriched in the promoters of similarly phased genes, some potentially associated with transcription factors.
• When considering the overlap in rhythmic gene expression and specific pathway behavior, thermocycles was the prevailing cue that controlled diurnal gene regulation. Taken together, our characterization of the rhythmic B. distachyon transcriptome represents a foundational resource with implications in other grass species.

中文翻译：

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环境温度的变化是决定 Brachypodium distachyon 昼夜基因调控的主要线索。

• 植物不断暴露于光照和温度的昼夜波动，以及其物理或生物环境的自发变化。生物钟以 24 小时为周期协调基因表达的调节，从而能够预测这些事件。
• 我们使用 RNA 测序来表征在光和温度循环以及恒定条件下的Brachypodium distachyon转录组。
• 大约 3% 的转录组受生物钟调节，比大多数其他物种报道的比例要小。对于在所有条件下都有节奏的大多数转录本，包括许多已知的时钟基因，在没有外部线索的情况下，基因表达的周期从 24 小时延长到 27 小时。为了在功能上表征B. distachyon中的循环转录组，我们使用了基因本体富集分析，并发现了几个与一天中特定时间的峰值表达显着相关的术语。此外，我们鉴定了富含相似阶段基因启动子的序列基序，其中一些可能与转录因子有关。
• 当考虑有节奏的基因表达和特定途径行为的重叠时，热循环是控制昼夜基因调控的主要线索。总之，我们对有节奏的B. distachyon转录组的表征代表了对其他草种具有影响的基础资源。