Submitted to: Physiological and Molecular Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 2, 2004
Publication Date: December 1, 2004
Citation: Navarre, D.A., Mayo, D. 2004. Differential characteristics of salicylic acid-mediated signaling in potato. Physiological and Molecular Plant Pathology. v. 64(4):179-188. Interpretive Summary: This work examines some of the factors influencing induced resistance in potato. Induced plant defenses are promising targets to improve plant disease resistance. Activating these defenses by spraying with environmentally friendly compounds has the potential to be used for disease control and reduce pesticide usage. Systemic Acquired Resistance (SAR) is the most studied type of induced resistant. We find key differences in SAR in potato compared to much better studied plants. These differences help clarify how SAR can be exploited in potato and suggest that SAR may have to be customized for each crop.
Technical Abstract: Potato has key differences in salicylic acid (SA) metabolism and signaling from tobacco and Arabidopsis. One difference is that potato has high basal salicylic acid concentrations in all tissues examined, including roots and tubers. Despite the high total SA concentrations, some potato varieties are able to maintain free SA levels as low as 0.5% of the total SA. Potato can also have high basal PR-1 expression and this appears to be a consequence of the high SA levels, because the expression is reduced in NahG plants. Despite the high SA levels, potato was nevertheless responsive to exogenous SA and as little as 250 µM SA induced PR-1 when sprayed on plants. Potato is also unusual in that PR-1 is strongly induced in leaf discs in the absence of any additional treatment. Furthermore, potato leaf discs are hypersensitive to BTH, with concentrations as low as 1 µM causing extensive cell death, whereas concentrations as high as 500 µM had no such effect on tobacco.