An unspecific phytotoxin oxalic acid and its effect on sunflower proteome

Abstract

Oxalic acid (OA) is found naturally in many plants and animals: it plays diverse roles in nature. It is an important pathogenicity determinant of many necrotrophic pathogens including Sclerotinia sclerotiorum (Lib.) de Bary. In order to understand the resistance mechanisms in Helianthus annuus L., a proteomic study was conducted on sunflower 12 h after inoculation by OA. A total of 17 differentially expressed proteins (either OA-induced or -suppressed proteins) were identified as a result of OA treatment. The candidate proteins were classified into two groups depending on their up/downregulation. The first group – upregulated proteins – included 13 proteins identified as being involved in the Calvin cycle, photosynthesis, programmed cell death (PCD) pathway, heat shock proteins, proteins with antioxidant activities and flavonol synthase (FLS). The second group – downregulated proteins – included those from the cupin family, ATP synthase subunit β, ketol-acid reducto-isomerase, and actin. Studying the biological significance of proteins responsive to OA might ultimately convey us to improve sunflower lines with higher levels of resistance to Sclerotinia and help to control this devastating necrotrophic plant pathogen.