The effect of abiotic and biotic stress on the salicylic acid biosynthetic pathway from mandelonitrile in peach

Abstract

HighlightWe show that the recently suggested third pathway for SA biosynthesis from mandelonitrile in peach is also functional under both abiotic and biotic stress conditions.AbstractSalicylic acid (SA) plays a central role in plant responses to environmental stresses via the SA-mediated regulation of many metabolic and molecular processes. In a recent study, we suggested a third pathway for SA biosynthesis from mandelonitrile (MD) in peach plants. This pathway is alternative to the phenylalanine ammonia-lyase pathway and links SA biosynthesis and cyanogenesis. In the present work, we show that this new SA biosynthetic pathway is also functional under abiotic (salt) and biotic (Plum pox virus infection) stress conditions, although the contribution of this pathway to the SA pool does not seem to be important under such conditions. Treating peach plants with MD not only affected the SA content, but it also had a pleiotropic effect on abscisic acid and jasmonic acid levels, two well-known stress related hormones, as well as on the H2O2-related antioxidant activities. Furthermore, MD improved plant performance under the stressful conditions, probably via the activation of different signaling pathways. We have thus proven that SA is not limited to biotic stress responses, but that it also plays a role in the response to abiotic stress in peach, although the physiological functions of this new SA biosynthetic pathway from MD remain to be elucidated.AbbreviationsABAabcisic acidAPXascorbate peroxidaseBAbenzoic acidCATcatalaseCNglcscyanogenic glycosidesMDmandelonitrileNPR1non-expressor of pathogenesis-related genePALphenylalanine ammonia-lyasePhephenylalaninePOXperoxidasePPVPlum pox virusSAsalicylic acidSODsuperoxide dismutaseTRXthioredoxins