PREDOMINANT EXPRESSION OF A PEROXIDASE GENE IN STAMINATE FLOWERS OF MERCURIALIS-ANNUA

A direct correlation between the feminizing process of male plants of Mercurialis annua by benzylaminopurine and the disappearance of male-s pecific peroxidases was established. In order to understand the proces s of hormonal regulation of the sexual differentiation and peroxidase activity, two peroxidase cDNA clones were selected from a male flower cDNA Library with degenerated oligonucleotide probes encoding a peroxi dase-specific site. These clones contained three peroxidase-specific s equences and an EcoRI restriction site. The two EcoRI fragments of one cDNA clone were subcloned and used as probes to analyse the expressio n of corresponding gene(s). The northern blot analysis showed hybridiz ation on a single mRNA band with a predominant expression in male flow ers. The feminizing treatment with a cytokinin induced the progressive disappearance of the hybridization signal in correlation with the dis appearance of male specific isoperoxidases.