Plant & Animal Genomes XI Conference Plant & Animal Genomes XI ConferenceJanuary 11-15, 2003
Town & Country Convention Center
San Diego, CA
Workshop: Plant Reproduction Comparative Genomics
Cucumis sativus, the cucumber, offers a few unique aspects for the study of plant reproductive biology. Its primordial floral buds respond to sex determining signals that induce the development of either male, female or bisexual flowers in typical patterns along the stems. A few sex determining genes have been identified at the classical genetic level, but their molecular identity and mode of action are yet to be elucidated. In this species, the floral differentiation program responds to several hormones that can alter flower sex, and serve as handles for molecular expression studies. The ABC developmental rules seem to operate in cucumber, and may shape its unisexual flowers by interacting with, or responding to, the genetic and hormonal sex expression mechanisms. We have taken molecular approaches to isolate genes that participate in this process. These included construction of segregating populations to map sex genes with molecular markers; differential screening for sex-specific mRNAs; looking at candidate genes that may be involved in the hormonal regulation of sex or in flower bud development. We followed the expression of genes encoding ethylene synthesis enzymes, ethylene receptors and MADS box proteins in contrasting sex genotypes. The tools available - DNA libraries, mapping populations and transformation protocols will be assessed. Current efforts in our group, as well as in other groups, to assemble the molecular data into a more comprehensive picture of sex expression in cucumber will be discussed.