Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 8, 2010
Publication Date: April 5, 2010
Citation: Kumar, M., Lulai, E.C., Suttle, J.C., Knowles, R. 2010. Age-Induced Loss of Wound-Healing Ability in Potato Tubers is Regulated by ABA [abstract.] Showcase 2010 Washington State University Abstracts. Available: http://showcase.wsu.edu/abstracts.aspx#edit Technical Abstract: Wounding of potato tubers stimulates the development of a suberized wound periderm that resists desiccation and microbial invasion. Wound-healing ability declines with advancing tuber age (storage period). The mechanism of age-induced loss in healing capacity is not known; however, older tubers have reduced abilities to upregulate superoxide production and phenylalanine ammonia lyase (PAL) activity in response to wounding. These processes are critical to the development of a suberized wound periderm. PAL is induced by abscisic acid (ABA). Therefore, the roles of ABA and PAL in the age-induced loss of wound-healing ability were examined. Wounding stimulated PAL activity regardless of tuber age, although the rate and extent of increase were significantly higher for younger tubers than for older tubers. In contrast to younger tubers, wounding did not induce PAL expression in older tubers until five days after wounding. ABA treatment increased PAL expression and activity in tissue from both ages of tubers and corrected the 5-day transcriptional delay characteristic of older tubers. Loss of wound healing ability with advancing tuber age is thus partly manifested by reduced ability to produce ABA and modulate the production of suberin phenolics through PAL in response to wounding. ABA treatment restored the healing ability of older tubers without restoring wound-induced superoxide-forming ability, suggesting a minimal role for wound-induced superoxide radicals in the oxidative coupling of phenolic monomers during suberization. However, the age-dependent loss of superoxide forming ability in response to wounding no doubt increases the susceptibility of older tubers to decay during wound-healing.