Biosciences Research Laboratory, USDA-Agricultural Research Service, 1605 Albrecht Blvd. N., Fargo, ND 58102-2765, USA.
Funct Integr Genomics. 2011 Dec;11(4):611-26. doi: 10.1007/s10142-011-0239-y. Epub 2011 Jul 26.
Leafy spurge (Euphorbia esula L.) is a herbaceous perennial weed that reproduces vegetatively from an abundance of underground adventitious buds (UABs), which undergo well-defined phases of seasonal dormancy (para-, endo-, and ecodormancy). In this study, the effects of dehydration stress on vegetative growth and flowering potential from endodormant UABs of leafy spurge was monitored. Further, microarray analysis was used to identify critical signaling pathways of transcriptome profiles associated with endodormancy maintenance in UABs. Surprisingly, only 3-day of dehydration stress is required to break the endodormant phase in UABs; however, the dehydration-stress treatment did not induce flowering. Previous studies have shown that prolonged cold treatment of UABs breaks endodormancy and induces a vernalization response leading to flowering. Thus, in this study, comparing transcriptome data from UABs exposed to short-term dehydration and vernalization provided a unique approach to identify overlapping molecular mechanisms involved in endodormancy maintenance and floral competence. Analysis of transcriptome data associated with breaking endodormancy by both environmental treatments identified LEC1, PHOTOSYSTEM I RC, and brassinosteroids as common central hubs of upregulated genes, while DREB1A, CBF2, GPA1, MYC2, bHLH, BZIP, and flavonoids were identified as common central hubs of downregulated genes. The majority of over-represented gene sets common to breaking endodormancy by dehydration stress and vernalization were downregulated and included pathways involved in hormone signaling, chromatin modification, and circadian rhythm. Additionally, the over-represented gene sets highlighted pathways involved in starch and sugar degradation and biogenesis of carbon skeletons, suggesting a high metabolic activity is necessary during the endodormant phase. The data presented in this study helped to refine our previous model for dormancy regulation.
多枝猪殃殃（Euphorbia esula L.）是一种多年生草本杂草，通过丰富的地下不定芽（UAB）进行营养繁殖，这些不定芽经历了明确的季节性休眠（拟休眠、内休眠和生态休眠）阶段。在这项研究中，监测了脱水胁迫对多枝猪殃殃内休眠 UAB 营养生长和开花潜力的影响。此外，还使用微阵列分析来鉴定与 UAB 内休眠维持相关的转录组谱的关键信号通路。令人惊讶的是，仅需 3 天的脱水胁迫即可打破 UAB 中的内休眠阶段；然而，脱水胁迫处理并没有诱导开花。先前的研究表明，UAB 的长时间冷处理会打破内休眠并诱导春化反应，从而导致开花。因此，在这项研究中，比较 UAB 暴露于短期脱水和春化处理的转录组数据提供了一种独特的方法来鉴定参与内休眠维持和开花能力的重叠分子机制。分析与两种环境处理打破内休眠相关的转录组数据，确定 LEC1、光系统 I RC 和油菜素内酯作为上调基因的共同中央枢纽，而 DREB1A、CBF2、GPA1、MYC2、bHLH、BZIP 和类黄酮被鉴定为下调基因的共同中央枢纽。通过脱水胁迫和春化作用打破内休眠的大多数过表达基因集都下调，包括参与激素信号、染色质修饰和昼夜节律的途径。此外，过表达基因集突出了与淀粉和糖降解以及碳骨架生物合成相关的途径，表明在内休眠阶段需要高代谢活性。本研究中提供的数据有助于完善我们以前的休眠调控模型。
