Isolation and characterization of a potato cDNA corresponding to a 1‐aminocyclopropane‐1‐carboxylate (ACC) oxidase gene differentially activated by stress

1‐Aminocyclopropane‐1‐carboxylate (ACC) oxidase enzyme catalyses the final step in ethylene biosynthesis, converting 1‐aminocyclopropane‐1‐carboxylic acid to ethylene. A cDNA clone encoding an ACC oxidase, ST‐ACO3, was isolated from potato (Solanum tuberosum L.) by differential screening of a Fusarium eumartii infected‐tuber cDNA library. The deduced amino acid sequence exhibited similarity to other ACC oxidase proteins from several plants species. Northern blot analysis revealed that the ST‐ACO3 mRNA level increased in potato tubers upon inoculation with F. eumartii, as well as after treatment with salicylic acid and indole‐3‐acetic acid, suggesting a cross‐talk between different signalling pathways involved in the defence response of potato tubers against F. eumartii attack.