Signals involved in tuber wound-healing.

The induction and regulation of wound-healing (WH) processes in potato tubers and other vegetables are of great nutritional and economic importance. The rapid accumulation of waxes to restrict water vapor loss and formation of suberin barriers to block infection are crucial components of WH. Recently we determined the regulatory involvement of abscisic acid (ABA) and ethylene in WH. In this addendum we integrate and interpret features from this recent research with additional information on ABA and data on the association of jasmonic acid (JA) in tuber WH. Results show that wounding dramatically increased tuber ethylene production and ABA and JA content. Blockage of wound-induced ABA biosynthesis and ethylene action/biosynthesis showed that ABA is a potent regulator in reduction of water vapor loss and hastening of suberization while ethylene had no discernable effect. The collective results also imply that ethylene has no effect on ABA regulation of WH. JA content in dormant and non-dormant mini-tubers is very low (< or = l ng gFW(-1)) but rapidly increases upon wounding then decreases, all before wound-induced ABA or ethylene accumulation reach their maxima. Results gathered to date do not support a role for ethylene in potato tuber WH but do implicate ABA in this process. Although JA content increases rapidly after wounding, its role in tuber WH remains speculative.