Abstract: RNA-based PCR amplification and Southern blotting of ACC oxidase cDNAs from peach ( Prunus persica L. ) fruits indicated that ACC oxidase mRNA was detected when fruit began to soften at about 75 d after bloom, and its accumulation peaked when the fruit mostly softened (about 1 kg/cm2). ACC oxidase mRNA was undetectable in green fruits and unripe fruits, but wounding and ethylene could induce ACC oxidase expression of these fruits. Similarly, ACC oxidase mRNA was undetectable in the alabastrum and petal just after anthesis and rapidly accumulated during senescence, and was induced by ethylene. Petal was more sensitive to ethylene than fruit. An increase in ACC oxidase mRNA level of leaf was found after 0.5 to 8 h of wounding, but ACC oxidase mRNA accumulated more rapidly after wounding in leaf than in fruit. Ethylene seemed to have little effect on ACC oxidase expression of leaf.

Key words: Prunus persica, ACC oxidase, Gene expression, PCR, Southern blots