SIPMEI, a pollen-specific gene in tomato

Abstract

Pectin is one of the main components of plant cell walls, and its biosynthesis is controlled by pectin methylesterase (PME). Pectin methylesterase inhibitors (PMEIs) are key regulators of PME. We report here the cloning and characterization of a novel Solanum lycopersicum L. PMEI gene, SlPMEI. RT-PCR studies of leaf, seed, fruit, flower, and flower organs confirmed that SlPMEI is expressed specifically in pollen. Promoter analysis of SlPMEI revealed pollen-specific cis-acting elements (pollen lat52 and g10). In addition, SlPMEI is expressed independently of abiotic stress, pathogen exposure, and growth stage in tomato, and a histochemical analysis of promoter activity revealed pollen-specific expression in both Arabidopsis and tomato. Under the microscope, we observed pollen-specific GUS expression in the stamen of transgenic tomato plant. These results indicate that the promoter of SlPMEI has strong pollen-specific activity, and could therefore be useful for development of industrially and agronomically important transgenic plants