Transcriptomic profiling of brassinosteroids response genes in moso bamboo (Phyllostachys heterocycla)

Brassinosteroids (BRs) are a group of plant steroid hormones that play crucial roles various of growth and developmental processes. Biological function and signal transduction pathway of BR has been well characterized in model plants like Arabidopsis and rice. However, their biological roles are still unclear in tree species, especially in an important non-timber plant moso bamboo, which has great ecological and economic value and distinguish fast-growth feature. Here we reported that reduce endogenous brassinosteroid by biosynthesis inhibitor propiconazole reduced both root and shoot growth in seedling stage. Exogenous BR application promoted shoot bract elongation and inclination of lamina joint and bract. Genome-wide transcriptome analysis were performed to identify hundreds of differential expressed genes by BR and propiconazole treatment in shoot and root parts of bamboo seedling, respectively. GO analysis revealed that BR regulates cell wall related genes, hydrogen peroxide catabolic genes and auxin related genes to promote bamboo root development and elongation. Our study identified BR response genes and provides a comprehensive resource for molecular mechanism research of bamboo growth. 18-day moso bamboo seedlings were transferred to 10 μM PPZ and mock medium for another 5 days. PPZ pre-treated seedlings were then treated with 1 μM BL or mock solution for 4 hours. Harvested seedling shoot and root separately, then isolated RNA was sequenced using Illumina Hiseq2500.