Systemic Potato virus Y^NTN infection and levels of salicylic and gentisic acids in different potato genotypes

Abstract

Endogenous levels of free and conjugated salicylic (SA) and gentisic (GA) acids, both putative signal molecules in plant defence, were analysed in order to investigate their involvement in the resistance of four potato ( Solanum tuberosum ) genotypes with different susceptibilities to Potato virus Y NTN (PVY NTN ) infection: the highly susceptible cv. Igor and its extremely resistant transgenic line, the extremely resistant cv. Sante and the tolerant cv. Pentland Squire. The lowest levels of free and conjugated SA were observed in the extremely resistant cv. Sante, while free GA, which was detected in all the other varieties, was absent. The extremely resistant transgenic cv. Igor contained the highest basal total SA level and the lowest level of total GA of all four cultivars. In susceptible cv. Igor, but not in resistant transgenic cv. Igor, a systemic increase of free SA was measured 1 day postinfection (dpi). Even more significant increases of free and conjugated SA and GA were detected 11 dpi when systemic symptoms appeared. In inoculated but not in upper noninoculated leaves of resistant transgenic cv. Igor, significant increase of SA conjugates occurred, but not before 11 dpi. The increase of SA and GA in susceptible cv. Igor could contribute to the general elevated levels of phenolic compounds as a response to stress caused by virus infection. It appears that basal levels of SA and GA do not correlate with resistance to PVY NTN in potato plants.

Multiple hormone analysis indicates involvement of jasmonate signalling in the early defence of potato to potato virus Y^NTN

“…Of the five hormones, SA predominated in both cultivars studied. These results are in accordance with the reports that potato contains higher basal level of SA than several other plants and that its high basal level is not related with resistance (Yu et al 1997, Krečič-Stres et al 2005.…”

“…In contrast to JA, our data indicate that SA is not a limiting factor involved in the very early response of potato plants to PVY NTN infection, possibly because of the high basal SA level in potato. Accumulation of SA in other susceptible potato-PVY NTN interaction observed later in the plant response (1 and 11 d after infection) suggests that SA contributes to the general elevated levels of phenolic compounds as a response to stress caused by virus infection (Krečič-Stres et al 2005). The present study also indicates that ABA and IAA are not implicated in early response of potato to PVY NTN infection although these plant hormones may play a role in defence against viruses (reviewed in Jameson and Clarke 2002, Whitham et al 2006, Cluver and Padmanabhan 2007.…”

“…This shift was not observed in the resistant cultivar. The involvement of salicylic acid in the PVY NTN -potato interaction was demonstrated by its induction one day post inoculation and later, when systemic symptoms appeared in a susceptible but not in a resistant cultivar (Krečič-Stres 2005).…”

Potato virus Y infection affects flavonoid profiles of Physalis angulata L.

“…Salicylic acid (SA) and methyl salicylate (MeSA) are phenolic compounds which play important roles as signals responsible to activate both local and systemic acquired resistance (SAR) (Vlot et al 2009). Besides these compounds, gentisic acid (GA; 2,5-dihydroxybenzoic acid), a common metabolic derivative of SA found in green plants, presents an important role in tomato-pathogen compatible interactions (Krečič-Stres et al 2005). A significant increase of a GA glycoside (5-O-b-D-xylopyranoside-GAX) was observed in the tomato-pathogen system formed by Solanum lycopersicum cv.…”

“…These metabolic changes can still be different in the local of infection or systemically (Krečič-Stres et al 2005;Choi et al 2006;Duarte et al 2008) and depending on the resistance of the plant to a specific pathogen (Krečič-Stres et al 2005).…”