An In Vitro Control Mechanism for Potato Stress Metabolite Biosynthesis

Abstract

Ethylene/oxygen (E/O2) elevates sesquiterpenoid stress metabolite (SSM) levels in potato (S. tuberosum L.) tuber tissue which is reacting hypersensitively. To determine whether E/O2 retards SSM turnover, a measured amount of rishitin was applied to tuber tissue which was then incubated in air of E/O2, and rishitin disappearance was monitored. No difference in the rate of rishitin disappearance was detected between air and E/O2 incubations. However, tissue treated with rishitin and incubated in E/O2 accumulated intermediates of the katahdinone and phytuberin pathways. This was not the case in rishitin-air treatments. These results suggest the dual involvement of ethylene and SSM intermediates in the regulation of the biosynthesis of SSM, compounds which may serve as phytoalexins.