Relation between ethylene-producing potential and gene expression of 1-aminocyclopropane-1-carboxylic acid synthase in Actinidia chinensis and A. deliciosa fruits

Abstract

Large differences in gene expression of 1-aminocyclopropane-1-carboxylic acid (ACC) synthase, ACC contents, and ACC synthase activity were found in different tissues of fruit between members of two kiwifruit species, (cv) Actinidia chinensis ('Kui mi') and A. deliciosa ('Hayward'). ACC synthase mRNA accumulated mostly in the outer pericarp, slightly in the inner pericarp, and in a trace quantity in the columella of 'Hayward' fruit that produces much less ethylene than does 'Kui mi'. However, gene transcripts at significant levels exist in all sections of 'Kui mi' fruit which reflects a large potential to produce ethylene. ACC levels and ACC synthase activities were much higher in all the tissues of 'Kui mi' fruit than in 'Hayward' fruit, which indicates that these enzymes are the primary cause for the varietal difference in the ability to produce ethylene in kiwifruit.