Chitinase-like1 Plays a Role in Stalk Tensile Strength in Maize.

Stalk lodging in maize () causes significant yield losses due to breaking of stalk tissue below the ear node before harvest. Here, we identified the maize () mutant in a F2 population. This mutant was characterized by highly brittle aerial parts that broke easily from mechanical disturbance or in high-wind conditions. The plants displayed a reduction in average stalk diameter and mechanical strength, dwarf stature, senescence at leaf tips, and semisterility of pollen. Histological studies demonstrated a reduction in lignin staining of cells in the mutant leaves and stalk, and deformation of vascular bundles in the stalk resulting in the loss of xylem and phloem tissues. Biochemical characterization showed a significant reduction in -coumaric acid, Glc, Man, and cellulose contents. The candidate gene responsible for phenotype is protein (), which is expressed at its highest levels in elongated internodes. Expression levels of secondary cell wall cellulose synthase genes () in the single mutant, and phenotypic observations in double mutants combining with or null alleles for two genes, confirmed interaction of with genes. Overexpression of enhanced mechanical stalk strength without affecting plant stature, senescence, or fertility. Biochemical characterization of overexpressing lines supported a role for ZmCtl1 in tensile strength enhancement. Conserved identity of CTL1 peptides across plant species and analysis of Arabidopsis () double mutants indicated that might have a conserved role in plants.