Transcriptome analysis on asymmetric growth of Oryza sativa root induced by brassinosteroid via ethylene pathway

The growth of plant roots is regulated by various factors. Brassinosteroids (BRs) can induce asymmetric growth of roots to form root coils and waves, and this phenomenon can be completely eliminated by ethylene inhibitors aminoacetic acid (AOA) or silver thiosulfate (STS), indicating this process depends on ethylene pathway. Nevertheless, the research on related genes has not been reported. In this study, Water, Brassinolide (BL), BL+AOA, and BL+STS four groups were set up using the root tips of Oryza sativa as subjects. The differentially expressed genes (DEGs) in the process of asymmetric root growth induced by BRs via ethylene pathway were identified by transcriptome sequencing, weighted gene co-expression network analysis (WGCNA), qRT-PCR and other techniques or methods. Finally, we screened 70 DEGs with high phenotypes correlation, including 1-AMINO-CYCLOPROPANE-1-CARBOXYLIC ACID OXIDASEs (OsACOs) and ETHYLENE-RESPONSIVE TRANSCRIPTION FACTORs (OsERFs) that regulated ethylene biosynthesis and signal transduction, and ALPHA-EXPANSINs (OsEXPAs) and WALL-ASSOCIATED RECEPTOR KINASE-LIKE 16 (OsWAKL16) that regulated cell elongation and expansion. In addition, ROOT MEADNDER CURLING (OsRMC), a receptor-like kinase (RLK) gene that inhibits root curling, was down-regulated in BL. The identification of the aforementioned genes provides strong evidence for revealing the molecular mechanism of asymmetric growth of O. sativa roots induced by BRs dependent on ethylene pathway.