Periderm disorder syndrome”: A new name for the syndrome formerly referred to as pink eye

Authors: Lulai, Edward; SABBA, ROBERT - North Dakota State University; NOLTE, PHILIP - Retired Non ARS Employee; GUDMESTAD, NEIL - North Dakota State University; SEOR, GARY - North Dakota State University

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/26/2017
Publication Date: 1/25/2018
Citation: Lulai, E.C., Sabba, R.P., Nolte, P.D., Gudmestad, N.C., Secor, G.A. 2018. "Periderm disorder syndrome": A new name for the syndrome formerly referred to as pink eye. American Journal of Potato Research. https://doi.org/10.1007/s12230-018-9634-4.

Interpretive Summary: Research results are presented which indicate that the name “Periderm disorder syndrome” (PDS) should replace the name of a disease that had been loosely termed potato tuber “Pink Eye.” The syndrome is a costly and unpredictable malady arising in potato tubers before harvest and results in serious defects in the protective surface tissues of potato tuber (periderm) which gives way to rot, dehydration and many food quality problems. The pinkish coloration associated with the syndrome is ephemeral, not causal, often not present and when present was often located between the eyes and various areas of the tuber surface. Clearly, a name employing “pink” and “eye” is not an appropriate or diagnostic name. Research results are consistent with previous findings indicating that the syndrome is directly related to the demise of actively dividing periderm cells (meristematic phellogen cells). The periderm of afflicted tubers becomes compromised and no longer competent as a barrier to infection and dehydration. The response of neighboring cells to produce a new protective (suberized) periderm barrier is haphazard and infective (disorderly); this confounds the recovery and further defines the nature of the syndrome as that of a periderm disorder. In conclusion, “Periderm Disorder Syndrome” is an accurate descriptive name for this erratic and costly problem and as such will more clearly focus related discussions and research to the core of the problem for a solution.

Technical Abstract: The “periderm disorder syndrome” (PDS), colloquially referred to previously as “pink eye”, is a physiological disorder caused by the death of the meristematically active layer of periderm cells (phellogen) and subsequent degeneration of the native periderm. This disorder occurs at a time when phellogen cell division is essential in the production of new periderm to cover/accommodate the expanding tuber surface and replace sloughed cells during later stages of rapid tuber growth. The characteristic degeneration and loss of the periderm, including the barrier provided by the suberized phellem, results in the induction of suberization; mainly accumulations of suberin polyphenolics (SPP) on neighboring cortical parenchyma cell walls in an erratic regenerative response to protect the vulnerable underlying tissues. Autofluorescence of the excessive accumulation of SPPs in freshly exposed cortical tissues located beneath the compromised periderm of afflicted tubers is a durable characteristic of extreme PDS. Conversely, the pinkish coloration sometimes associated with the PDS often is not present, and if present is frequently barely discernable and ephemeral; therefore the pinkish coloration is not a reliable diagnostic nor does it lend itself to an appropriate name. Rather the syndrome is characterized by degeneration of the periderm and induction of erratic regenerative responses (mainly SPP accumulations) that are diagnostic and indicative of PDS. As such, “Periderm Disorder Syndrome” is a more accurate and descriptive name for this erratic and costly problem.