Impact of Bikinin on Brassinosteroid Signaling Pathway and its Influence on Barley Development

Abstract

Impact of bikinin, a Glycogen Synthase Kinase 3 (GSK3) inhibitor, on long-term response of barley after spraying. Using three different concentrations of 10 µM, 50 µM, and 100 µM bikinin led to distinct phenotypic changes in shoot and root growth, leaf development, and photosystem II efficiency. Transcriptomic analysis revealed genotype-dependent responses, with Golden Promise exhibiting more significant changes than Haruna Nijo. Expression pattern of genes controlling the Brassinosteroid signaling pathway, as well as Western blot analysis, showed constitutive expression of HvGSK genes and HvGSK2.1 kinase activity in barley after bikinin treatment. On the other hand, analysis showed varied phosphorylation levels of HvBZR1 in response to high concentrations of bikinin, particularly in Golden Promise. The study contributes to understanding the intricate role of GSK3 in barley growth and the genotype-dependent effects of bikinin. Additionally, the research highlights the potential of bikinin as a tool for studying the Brassinosteroid-dependent pathways. This study provides valuable insights into the molecular mechanisms underlying barley responses to bikinin, shedding light on the complex interplay between GSK, BZR1, and Brassinosteroids in monocotyledonous plants.