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United States Department of Agriculture

Agricultural Research Service

Title: Relationship Between Pink Eye Symptoms and Cell Damage in the Tuber Periderm and Cortex

Authors
item Sabba, Robert - UNIV OF MADISON-WI
item Bussan, Alvin - UNIV OF MADISON-WI
item Lulai, Edward

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 12, 2008
Publication Date: October 15, 2008
Repository URL: http://hdl.handle.net/10113/41600
Citation: Sabba, R.P., Bussan, A.J., Lulai, E.C. 2008. Relationship Between Pink Eye Symptoms and Cell Damage in the Tuber Periderm and Cortex. American Journal of Potato Research. 85(6):466-476.

Interpretive Summary: Pink eye (PE) is a potato tuber disorder that leads to processing complications and bud-end rot that develops while the potatoes are in storage. Despite the adverse effects and costs of PE for the potato processing industry, limited progress has been made in understanding the physiological basis of this disorder and how it may be prevented. Although the internal autofluorescence that characterizes PE has been described, the external symptoms of PE have not been well characterized or related to internal cellular symptoms. It is of vital importance to determine the physiological and cytological effects of PE in order to understand how it is caused and to develop effective management strategies to prevent the disorder. External symptoms progressed from pinkish discoloration around tuber eyes to water-soaked and corky patch lesions. Internal symptoms progressed from erratic browning around cortical cell walls to necrotic zones and cells with dark, circular inclusions. The areas associated with these internal symptoms often became surrounded by an internal PE-related periderm. Although a healthy native periderm possesses surface cells, i.e. the skin, that are modified to protect underlying tissues, the native periderm of PE tubers often became compromised or lost. Vital staining with fluorescein diacetate showed that cortical cells underneath the native periderm became non-viable in PE tissue. Immunological analyses indicated that key cell wall components, i.e. homogalacturonan and extensin, were not altered in pink eye afflicted tissues. These results conclusively show that the PE disorder results in or is caused by cell death in tissue underneath the PE afflicted periderm, but does not lead to cell wall breakdown which is often characteristic of pathogen activity.

Technical Abstract: Pink eye (PE) is a tuber disorder that leads to processing complications and bud-end rot in storage. Despite the significance of PE for the potato processing industry, limited progress has been made in understanding the physiological basis of this disorder. Although the internal autofluorescence that characterizes PE has been described, the external symptoms of PE have not been well characterized or correlated with internal cellular symptoms. It is of vital importance to determine the physiological and cytological effects of PE in order to understand how it is caused and to develop effective management strategies to prevent the disorder. External symptoms progressed from pinkish discoloration around tuber eyes to water-soaked and corky patch lesions. Internal symptoms progressed from erratic browning around cortical cell walls to necrotic zones and cells with dark, circular inclusions. These areas often became surrounded by an internal PE-related periderm, while the native periderm often became compromised or lost. Vital staining with fluorescein diacetate showed that cortical cells underneath the native periderm became non-viable in PE tissue. Immunolocalization of homogalacturonan and extensin epitopes indicated that these cell wall polymers were not altered in pink eye afflicted tissues. These results conclusively show that the PE disorder results in or is caused by cell death in tissue underneath the PE afflicted periderm, but does not lead to cell wall breakdown which is often characteristic of pathogen activity.

Last Modified: 11/23/2014
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