Dynamics of Responses in Compatible Potato - Potato virus Y Interaction Are Modulated by Salicylic Acid

Abstract

To investigate the dynamics of the potato – Potato virus Y (PVY) compatible interaction in relation to salicylic acid - controlled pathways we performed experiments using non-transgenic potato cv. Désirée, transgenic NahG-Désirée, cv. Igor and PVYNTN, the most aggressive strain of PVY. The importance of salicylic acid in viral multiplication and symptom development was confirmed by pronounced symptom development in NahG-Désirée, depleted in salicylic acid, and reversion of the effect after spraying with 2,6-dichloroisonicotinic acid (a salicylic acid - analogue). We have employed quantitative PCR for monitoring virus multiplication, as well as plant responses through expression of selected marker genes of photosynthetic activity, carbohydrate metabolism and the defence response. Viral multiplication was the slowest in inoculated potato of cv. Désirée, the only asymptomatic genotype in the study. The intensity of defence-related gene expression was much stronger in both sensitive genotypes (NahG-Désirée and cv. Igor) at the site of inoculation than in asymptomatic plants (cv. Désirée). Photosynthesis and carbohydrate metabolism gene expression differed between the symptomatic and asymptomatic phenotypes. The differential gene expression pattern of the two sensitive genotypes indicates that the outcome of the interaction does not rely simply on one regulatory component, but similar phenotypical features can result from distinct responses at the molecular level.

Salicylic acid and gentisic acid induce RNA silencing-related genes and plant resistance to RNA pathogens

“…In this sense, elevated levels of SA are found in many incompatible plant-pathogen interactions but also in some compatible ones (Baebler et al, 2011;Bellés et al, 1999) and exogenous treatments with SA induce in the plant the synthesis of a group of proteins that are collectively referred to as pathogenesis-related (PR) proteins, many of which have antimicrobial properties (van Loon et al, 2006). Moreover, nahG plants, which are unable to accumulate SA, are more susceptible to pathogens (Vlot et al, 2009).…”

Reactive oxygen and nitrogen species and hormone signalling in systemic infection of pea by Pea enation mosaic virus

“…At later stages the SA concentration decreased. Similarly, in compatible potato-Potato virus Y interaction, the dynamics of the responses was shown to be modulated by SA, which can delay viral multiplication and disease symptoms (Baebler et al 2011). The enhanced SA levels were found to coincide with the rise in CaMV levels in A. thaliana (Love et al 2005).…”

“…SA is involved in the activation of plant resistance to biotrophic and hemi-biotrophic parasites, as well as in the establishment of systemic acquired resistance (Glazebrook 2005;Bari & Jones 2009). In compatible plant-virus interactions, the dynamics of plant responses was shown to be modulated by SA, which was found to be able to delay viral multiplication and the appearance of disease symptoms (Baebler et al 2011). Exogenous application of SA is usually reported to induce resistance to viruses, though exceptions were reported (reviewed by ).…”

Modulation of host plant immunity by Tobamovirus proteins

“…We hypothesized that at early stages, the movement of viral RNA between adjacent cells was facilitated by MP expression as was previously reported (Guenoune-Gelbart et al, 2008;Niehl and Heinlein, 2011), and that was the reason why the virus achieved a systemic infection faster that wild-type infected plants. It could also be argued that the enhanced expression of b 1-3 glucanases (PR-2) in MP-expressing lines might facilitate virus movement due to degradation of callose in plasmodesmata (Baebler et al, 2011). At late stages, the recovery phase observed in MP-expressing lines could arise from the combined effect of enhanced transport of vsiRNAs and also be due to the defence elicitation induced by ROS and SA.…”