Genome-wide Transcriptome Profiling Reveals the Mechanism of the Effects of Uniconazole on Root Development in Glycine Max

Uniconazole, a plant growth retardant, possesses the ability to improve quality and increase tolerance of plant. However, it is known little about the effects of uniconazole on root. In this study, uniconazole treatments that were applied through seed soaking, promoted soybean root development, and the microstructure of root showed increase of cortical thickness and cortex cell width. Meanwhile, the endogenous hormone content also altered in root after uniconazole treatments. To obtain the molecular mechanism underlying the effects of uniconazole on root, we performed an RNA-seq of roots harvested 3 days after uniconazole treatment. Through analyses of phytohormone-associated genes for endogenous hormones changes, we found that not only GA biosynthesis pathway but also the regulation genes of the pathway were affected. Above all, the dominant pathway plant hormone signal transduction may be the main factor of the cambium proliferation, in especial ethylene/ERF signaling pathway. Moreover, the transcriptome demonstrated differentially expressed genes that determined cell division and cell wall modification may be regulators of root growth. CLE signaling and receptor-like kinases may play a crucial role in the root elongation. Besides, 177 transcription factors (TFs) were involved in response to uniconazole. Taken together, all these findings provide insights into the complex molecular mechanisms associated with root development after uniconazole treatment.