Submitted to: American Journal of Potato Research
Publication Type: Abstract Only
Publication Acceptance Date: July 15, 1996
Publication Date: N/A
Technical Abstract: Wilt diseases (Verticillium sp. and Fusarium sp.) often spread from the growing stem into the vascular tissue of the tuber. Infected xylem vessels of tubers become discolored creating a serious market quality defect that often prevents sale of raw product to its primary market. Despite losses created by these infections, potato resistance responses to wilt infections are poorly defined. Using histochemical techniques, we identified a tuber-pathogen resistance response to natural wilt infections and to laboratory scale fungal challenges of tuber xylem vessels. Cortical cells surrounding the infected/challenged xylem responded to the fungal invasion by depositing lignin-like phenolics onto their cell walls. Following significant deposition of lignin-like phenolics, aliphatic materials were laid down onto the lignified cell walls. This process of internal suberization occurred without wounding. Consequently, the typical wound induced signal that normally initiates suberization was absent. Instead, the suberization signal was derived from the plant-pathogen interaction. We believe this to be the first report for such a resistance response to Verticillium sp. in potato tuber.