Microtubules and their regulatory proteins are involved in the regulation of plant cell morphology. SPIRAL1 (SPR1), a plant-specific microtubule-binding protein, is critical in regulating the anisotropic growth of plant cells. Our previous study showed that overexpressed Salix SmSPR1 genes in Arabidopsis thaliana caused right-handed spiral elongation in etiolated seedlings, but there were no morphological differences between wild-type and transgenic seedlings under varied light conditions. We then studied the transcriptional regulation patterns in transgenic plants engineered with the SmSPR1 gene. Transcriptomic results showed that a large number of differentially expressed genes were involved in plant light signal reception, chlorophyll synthesis and photosystem structure. Eleven gene families with 42 photosynthesis-related genes and 6 light-responsive genes were involved in regulation of cell morphology. Our results showed that these genes in the SmSPR1-ox line were particularly down-regulated under dark conditions. In addition, 33 TFs showed differences between SmSPR1-ox and wild-type lines. Taken together, the transcriptome analysis provides new insight into investigating the molecular mechanisms of light-induced cell morphological changes mediated by the microtubule binding protein SPR1.

微管及其调节蛋白参与植物细胞形态的调节。SPIRAL1（SPR1）是一种植物特有的微管结合蛋白，在调节植物细胞的各向异性生长中至关重要。我们以前的研究表明，拟南芥中过量表达的Salix SmSPR1基因导致黄化幼苗的右旋螺旋伸长，但是在不同光照条件下野生型和转基因幼苗之间没有形态差异。然后，我们研究了用SmSPR1设计的转基因植物中的转录调控模式基因。转录组结果表明，大量差异表达的基因参与植物光信号的接收，叶绿素的合成和光系统的结构。具有42个光合作用相关基因和6个光响应基因的11个基因家族参与细胞形态的调节。我们的结果表明，SmSPR1-ox系中的这些基因在黑暗条件下特别下调。另外，有33个TFs显示出SmSPR1-ox和野生型品系之间的差异。两者合计，转录组分析提供了新的见解，以调查由微管结合蛋白SPR1介导的光诱导细胞形态变化的分子机制。