HYPOXIC STRESS INHIBITS MULTIPLE ASPECTS OF THE POTATO-TUBER WOUND RESPONSE

Potato (Solanum tuberosum L.) tubers subjected to wounding under hypoxic stress do not synthesize RNA species that are induced in response to wounding in aerobic conditions. Further, wound-response proteins fail to be synthesized when wounded tubers are transferred to hypoxic conditions although messenger RNAs which encode them persist for many hours after transfer. Hypoxic stress also prevents the incorporation of [3H]thymidine by wounded tubers that occurs in aerobic conditions. In contrast, hypoxic tubers accumulate and translate transcripts of genes whose products are involved in anaerobic metabolism whether or not they are wounded. Both the hypoxic response and the aerobic wound response preclude the synthesis of proteins encoded by messenger RNAs which accumulated during the tuberization process and which can be translated in vitro. Finally, wounding elicits the degradation of a subset of these tuberization-associated transcripts. These data indicate a complex and precise regulation of gene expression at several levels of macromolecular synthesis.