ZmDRR206 involves in maintaining cell wall integrity during maize seedling growth and interaction with the environment

Abstract Plants adaptively change their cell wall composition and structure during their growth, development, and interactions with environmental stresses. Dirigent proteins (DIRs) contribute to environmental adaptations by dynamically reorganizing the cell wall and/or by generating defense compounds. Here, we established that maize DIR, ZmDRR206, mediates maize seedling growth and disease resistance by coordinately regulating biosynthesis of cell wall components for cell wall integrity (CWI) maintenance. The expression of ZmDRR206 increased rapidly in maize seedling upon pathogen infection. Both overexpression and mutation of ZmDRR206 resulted in small kernel and diminished seedling growth; while ZmDRR206-overexpression increased disease resistance, enhanced drought tolerance and reduced photosynthetic activity, thus caused the maize seedlings to show a growth and defense trade-off phenotype. Consistently, ZmDRR206-overexpression reduced the contents of primary metabolites and down-regulated the photosynthesis-related genes; while increased the contents of major cell wall components and defense phytohormones and up-regulated defense- and cell wall biosynthesis-related genes in maize seedlings grown under non-stress conditions. Furthermore, ZmDRR206 physically interacted with ZmCesA10 in yeast and in planta. Our findings unravel a mechanism that ZmDRR206 coordinately regulates biosynthesis of cell wall components for CWI maintenance during maize seedling growth, providing opportunities for breeding strong disease resistance in maize.