| Abstract Detail
Physiology Lulai, Edward C. [1], Weiland, John J. [2], Suttle, Jeffrey C. [1]. Pink Eye: An Unusual Tuber Disorder Characterized by Compromized Periderm, Aberrant Suberization and Related Susceptibility to Infection. POTATO tuber Pink Eye (PE) is a disorder of unknown origin that results in significant postharvest quality deterioration and rot. Little is known about the physiology of PE, including the characteristic tissue autofluorescence (AF) that defines the PE syndrome. The research objective was to identify the source of PE induced AF and PE related susceptibility to infection. The suberized barrier of the native periderm and neighboring tissues were investigated to determine their role in the PE disorder. The results showed that the integrity of the suberized barrier of the native periderm, i.e. phellem, was compromised or in some places absent in PE tubers. The PE complex was further characterized by induction of unusual and erratic suberin poly(phenolic) (SPP) accumulations in the cortical parenchyma followed by latent suberin poly(aliphatic) (SPA) accumulations. Both accumulations were generally insufficient to form a complete barrier that was competent to block infections by bacteria and fungi. These anomalies and deficiencies generally started at the bud end of the tuber, leaving these and other PE-afflicted areas without a comprehensive barrier to infection, as evidenced by the presence of Rhizoctonia solani hyphae in a few samples. PE afflicted areas had high water vapor conductances, putatively due to the absence of suberin associated waxes; water vapor losses are known to cause tuber shrinkage and flaccidity. Widespread erratic accumulations of SPP on cortical parenchyma cell walls were found to be the source of AF commonly used to detect PE. The results of this study provide convincing evidence that PE is a physiological disorder in which the native periderm is disrupted in the growing tuber and internal suberization is induced. The compromised native periderm and the incomplete internal suberization lack the integrity to provide an effective barrier to infections. This may explain the previous inconsistent associations of various pathogens with PE.
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1 - USDA-ARS Northern Crop Science Lab, Sugarbeet & Potato Research Unit, 1307 18th St N, Fargo, ND, 58105-5677, USA
2 - USDA-ARS, Northern Crop Science Laboratory, Sugarbeet & Potato Research Unit, 1307 18th St. N, Fargo, ND, 58105, USA
Keywords:
Potato
suberin
pink-eye
suberin poly(phenolic)
suberin poly(aliphatic).
Session: PAA05-8
Location: Hall of Ideas Room F/Monona Terrace
Date: Thursday, July 27th, 2006
Time: 10:45 AM
Abstract ID:177 |
