The role of Populus <i>MYB94</i> transcription factor in seed germination requires the expression of ABA-responsive genes

Plant seed germination is easily influenced by endogenous gene expression, hormones and environmental conditions. Here, we investigated a Populus R2R3-MYB transcription factor (referred to as <i>MYB94</i>) that plays a role in seed germination in close relation to the hormone abscisic acid (ABA). Two independent Arabidopsis transgenic lines overexpressing <i>MYB94</i> (Oe-lines) and wild-type (Wt) were no clear differences in the seed germination rates under normal conditions, but the germination rates of the two Oe-lines were both significantly delayed under ABA treatment. This delay in germination is most likely associated with the endogenous hormone abscisic acid (ABA). We find that the transcript levels of several representative genes in relation to ABA synthesis or signaling in the <i>MYB94 </i> Oe-lines showed significantly increased compared with those of the Wt plants. Taken together, our results here reveal the role of the Populus R2R3-MYB transcription factor <i>MYB94</i> in regulating the ABA-responsive genes in plant seed germination.植物种子萌发极易受内源基因表达、激素及环境条件的影响。本研究聚焦于一种杨属（Populus）R2R3-MYB转录因子（下称<i>MYB94</i>），其在植物种子萌发过程中发挥调控功能，且与激素脱落酸（abscisic acid，ABA）紧密相关。我们构建了两株独立的过表达<i>MYB94</i>的拟南芥转基因株系（过表达株系，Oe-lines）及野生型（Wt）对照；在正常培养条件下，二者的种子萌发率无显著差异，但经ABA处理后，两株过表达株系的种子萌发速率均显著延后。此种萌发延迟现象极有可能与内源激素脱落酸（ABA）相关。我们发现，相较于野生型植株，过表达<i>MYB94</i>的株系中，若干与ABA合成或信号通路相关的代表性基因的转录本水平均显著上调。综上，本研究结果揭示了杨属R2R3-MYB转录因子<i>MYB94</i>通过调控ABA响应基因参与植物种子萌发的生物学功能。