|Freeman, Thomas - ND STATE UNIVERSITY|
Submitted to: Potato Association of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: March 27, 2000
Publication Date: N/A
Technical Abstract: Native periderm, the dermal tissue of potato tuber, provides an essential barrier to pathogens. The cell walls of the outer group of peridermal cells, phellem cells, are laminated with suberin, a complex, inert biopolyester, which provides a protective barrier for the tuber. Suberin is composed of two distinctly different biochemical components; a polyphenolic component and a polyaliphatic component. Tubers entering storage and cut seed tubers require rapid suberization of wounded areas to avoid disease and excessive shrinkage. Despite the importance of wound induced suberization, very little is known about the biochemical mechanisms that regulate suberization. We have investigated processes that may be involved in these regulatory mechanisms. Certain periderm and wound related metabolites were found to have drastic effects on suberin polyphenolic accumulation. Delay of polyphenolic accumulation also inhibited subsequent suberin polyaliphatic accumulation. Coumarins, which have been shown by others to be present in native periderm and possibly linked to some peridermal diseases, were potent inhibitors of suberin polyphenolic accumulation during wound healing. The coumarin esculetin inhibited peroxidase activity, a key enzyme in suberization. These results are important in determining what factors influence and regulate suberization and the development of resistance to infection.