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

Abstract

The physiological responses of pea plants during 40 days of compatible interaction with Pea enation mosaic virus (PEMV) were evaluated. PEMV induces systemic changes in the concentration of phytohormones. At 5 days post inoculation (dpi), a simultaneous increase in abscisic acid (ABA) level and a decrease in salicylic acid (SA) level was observed, which is known to be involved in the suppression of hypersensitive reaction. In our pathosystem it preceded the virus presence in the systemic leaves. PEMV induces the accumulation of ABA, SA and Hsp70 and enhances peroxidase (POX) activity at 15 dpi, when it is already transmitted throughout the plant. The formation of enations was preceded by a local accumulation of nitric oxide, which was followed by the appearance of reactive oxygen species, mostly in the vicinity of leaf veins. Such heterogeneity suggests involvement of these molecules in the control of hyperplasia and tissue differentiation.