Potential Involvement of Cell Cycle-Related Genes in the Arrest of Stamen Development of Female Flowers During Sex Expression in Cucumber (Cucumis sativus L.)

摘要

Monoecious cucumber (Cucumis sativus L.) produces male and female flowers on the same plant, but application of ethylene promotes expression of female flowers. In the early bisexual stage, all flower buds contain primordia for both stamens and pistils and sexual differences are established by the selective arrest of sexual organ primordia. The expression of six cell cycle-related genes [Cs Cyclin A (CsCycA ), CsCycB , CsCycD3; 1 , CsCycD3; 2 , Cs Cyclin-dependent kinase A (CsCDKA ), and CsCDKB ] was analyzed in male and female flower buds to investigate cell cycle activity in sexual organs. CsCycA was expressed specifically in the area containing arrested stamen primordia (ACASP) in female flower buds, but was barely detected in male flower buds. Expression of the other five genes was detected in the ACASP but not in pistils of female flower buds. Expression of all six genes was elevated transiently following the application of 2-chloroethylphosphonic acid (ethephon), an ethylene-releasing agent, to the shoot apices. The correlation of expression of these genes with the formation of female flowers suggests they play a role in the arrest of stamens of female flowers in monoecious cucumber plants.