The Transcriptomic Analysis On Gene Expression Pattern In Arabidopsis Roots Under Different Light Conditions

Root is the organ of the most plants grown in the underground, it can provide mechanical support for plant growth vertically, and absorb water and minerals from the soil. The development and morphogenesis of roots is one of the most important aspects of plant growth. Light is the one of the most critical factors, it not only is the source of photosynthesis energy, but also mediates gene expression, influencing the activity of enzyme, and affects many aspects of plant growth and photomorphogenesis, makes plants to adapt to environment better. Arabidopsis is one of the model plant, in plant science, researchers have been using the agar-plate culture Arabidopsis, this method is simple, and it is easy to observe the growth conditions (especially the roots). However, researchers have no enough attention to the Arabidopsis roots growth under the light, recent years, people proposed to improve the agar-plate system, makes the shoots grown under light and roots grown in darkness, studied the Arabidopsis roots morphogenesis in labratory condition, they measured many physiological indicators of Arabidopsis seedlings roots morphogenesis, but had no a whole understanding in molecular level about the growth environment.This experiment was conducted under three different light conditions to culture Arabidopsis, they are Traditional Plate Growth (TPG) that the shoots and roots are illuminated, Improved Plate Growth (IPG)that shoots are illuminated and roots are grown in darkness, Soil Growth (SG). When cultured after 15 days, the RNA of Arabidopsis roots in the three growth conditions was extracted and sent to the transcriptome sequencing. We got the following conclusions through high throughput sequencing:there are 141 differential expression genes between TPG and IPG,2471 differential expression genes between TPG and SG,2245 differential expression genes between IPG and SG. Through the GO analysis of differential expression genes, there are 83 differential expression genes were upregulated between TPG and IPG, 58 differential expression genes were downregulated, the 141 differential expression genes were mainly focused on the biological process and molecular function of GO categories. The differential expression genes were enriched to the KEGG pathway, we found that the flavones and flavonols biosynthesis pathway, and the flavonoids biosynthesis pathway were the most affected pathways. At the same time, we selected 20 differential expression genes with qRT-PCR, the results suggested the correlation coefficient between transcriptome data and qRT-PCR data is above 80 percent. In conclusion, we can understand the changes of gene expression through high throughput sequencing, and provide the background for the laboratory studies on Arabidopsis, provide the reference for screening and identifying Arabidopsis mutants.