Local and systemic gene expression in potato infected with PVY

The goal of these studies is analysis of gene expression profiles in potato plants infected with potato virus Y (necrotic strain - PVYN). A prototypic plant pathogen interaction system used to study disease resistance is tobacco (Nicotiana tabacum) and tobacco mosaic virus (TMV). In tobacco, the resistance response comprises two phenomena, known as the hypersensitive response (HR) and systemic acquired resistance (SAR). HR is typically characterized by a local necrosis surrounding the site of viral entry leading to restriction of pathogen replication and spread. SAR is the enhanced ability of the plant to resist a secondary challenge by the same or a different pathogen inoculated elsewhere on the plant. The identity of the signal(s) that induces HR and SAR is still poorly understood. Plants of S. tuberosum cv. Rywal, resistant to all known (N, 0, NTN) PVY strains, were grown in growth chambers using 16 h period of light (22°C) and 8 h of darkness (18°C). For all experiments, 6-week-old plants were used. For inoculation with PVY, carborundum-dusted leaves were rubbed with water (mock control) or PVYN solution (1 µg ml-1). Two to four leaves were inoculated on each plant and harvested together at 1, 3, and 6 days post inoculation (dpi). Separately, noninoculated leaves were harvested at the same time points (upper leaves). The first time point (1 dpi) has been chosen to study the early stage of plant response before necrotic lesion formation. At 3 dpi necrotic lesions start to appear, and at 6 dpi necroses are fully developed which correlates with the maximum of salicylic acid increase in virus inoculated leaves. Keywords: Direct comparison 26 hybs total