ZmMYB92 modulates secondary wall cellulose synthesis in maize

Abstract

Lodging resistance, a pivotal determinant for crop stability and yield of maize, is chiefly governed by the mechanical attributes of cell walls, particularly the secondary cell walls (SCWs). Cellulose, the predominant constituent of SCWs, serves a vital function in physical support. Despite its significance, the regulatory mechanisms orchestrating SCW cellulose biosynthesis in maize remain elusive. In this investigation, we identify and characterize ZmMYB92, a transcription factor (TF) from the R2R3-MYB family, as a pivotal regulator of SCW biosynthesis in maize. Mutations in ZmMYB92 result in an altered phenotype characterized by increased stem brittleness, diminished cellulose content, and thinner cell walls, especially in stems and leaf veins. ZmMYB92 directly binds to the cis elements of the ZmCesA10 and ZmCesA11 promoters to activate their expression. The transcriptionally binding cis elements of ZmMYB92 are summarized. These findings provide a foundation for further modulation of cell wall properties and subsequent maize improvement.

Keywords: ZmMYB92; cellulose; maize (Zea mays); secondary cell wall.