Expression of Two 1-Aminocyclopropane-1-Carboxylate Synthase Genes, CS-ACSI and CS-ACS2, Correlated with Sex Phenotypes in Cucumber plants (Cucumis sativus L.).

Ethylene regulates the sex expression in cucumber plants (Cucumis sativus L.). We examined expression of two 1-aminocyclopropane-1-Carboxylate (ACC) synthase genes, CS-ACS1 and CS-ACS2, at the apices of isogenic gynoecious (FF) and monoecious (ff) cucumber lines. The transcripts of CS-ACS1 and CS-ACS2 were detected at the apices of gynoecious line. On the other hand, only the CS-ACS2 transcript was detected at the apices of monoecious line. The expression of CS-ACS2 at the apices was localized to the floral buds that would develop into female flowers. These results suggest that the differentiation of female flowers at the apices of isogenic gynoecious and monoecious cucumber plants is regulated by the levels of both CS-ACS1 and CS-ACS2 mRNA at the apices.