DEFECTIVE EMBRYO AND MERISTEMS1 (DEM1) Is Essential for Cell Proliferation and Cell Differentiation in Tomato

Most flowering plant species contain at least two copies of the DEFECTIVE EMBRYO AND MERISTEMS (DEM) gene with the encoded DEM proteins lacking homology to proteins of known biochemical function. In tomato (Si; Solanum lycopersicum), stable mutations in the S1DEM1 locus result in shoot and root meristem defects with the dem1 mutant failing to progress past the cotyledon stage of seedling development. Generation of a Somatic Mutagenesis of DEM1 (SMD) transformant line in tomato allowed for the characterization of S1DEM1 gene function past the seedling stage of vegetative development with SMD plants displaying a range of leaf development abnormalities. Further, the sectored or stable in planta expression of specific regions of the S1DEM1 coding sequence also resulted in the generation of tomato transformants that displayed a range of vegetative development defects, which when considered together with the dem1 mutant seedling and SMD transformant line phenotypic data, allowed for the assignment of S1DEM1 gene function to early embryo development, adaxial epidermis cell development, lateral leaf blade expansion, and mesophyll cell proliferation and differentiation.

Automated summary

Most flowering plant species have at least two copies of the DEFECTIVE EMBRYO AND MERISTEMS (DEM) gene, with mutations in the S1DEM1 locus in tomato causing shoot and root meristem defects. The characterization of S1DEM1 gene function in tomato revealed its role in various stages of vegetative development.