The Effect of Oxalic Acid, the Pathogenicity Factor of Sclerotinia sclerotiorum on the Two Susceptible and Moderately Resistant Lines of Sunfl ower

Abstract

BackgroundOne of the main sunflower diseases is the white mold Sclerotinia sclerotiorum. The oxalic acid (OA), which is one of the main pathogenicity factors of this fungus, beside the direct toxicity on the host, has other functions such as the disruption of the cell wall and chelating out the calcium ions.ObjectivesRegarding the importance of this disease, it is important to study the reactions of the plant against OA which is a nonspecific toxin of many other necrotrophic fungi.Materials and MethodsIn this study, two susceptible and moderately resistant sunflower lines were inoculated with OA and samples at the first leaf stage were collected within the intervals of 2, 6, 12 and 24 hours post inoculation. The expression of five genes related to tricarboxylic acid cycle, including citrate synthase, fumarase, iso-citrate lyase, malate synthase and malate dehydrogenase was studied under OA treatment.ResultsTwo hours after the inoculation, no significant change was observed in the expression of the five studied genes in the moderately resistant line. The iso-citrate lyase gene, which is related to glyoxylate cycle (a variation of the tricarboxylic acid cycle), showed no change in the moderately resistant line; however, it showed an increase in the susceptible line. The increase in fumarase gene expression in moderately resistant line was higher than the susceptible line. The result showed the activation of glyoxylate cycle and destruction of fatty acids in the susceptible line.ConclusionsActivation of glyoxylate cycle indicated induction of senescent symptoms by OA in susceptible line. Increasing in H2O2 leads to oxidative burst and cell death. Cell death has an apparent benefit for development and growth of necrotrophic pathogens in the plant cells. The study of resistance mechanisms in response to the pathogen is useful for breeding programs to provide lines with higher resistance to this pathogen.

Optimization of scleroglucan production by Sclerotium rolfsii by lowering pH during fermentation via oxalate metabolic pathway manipulation using CRISPR/Cas9

“…Oxalic acid is the main acidic metabolite in S. rolfsi and in many other fungi, such as Sclerotinia sclerotiorum [ 13 ]. Oxalic acid has been reported to be directly toxic to plant tissues [ 14 ], as it is one of the strong organic acids that is 10,000-times more acidic than acetic acid.…”

A Strategy for Scleroglucan Production in Sclerotium Rolfsii: Lowering pH in Fermentation Process by Manipulating Oxalate Metabolic Pathway With CRISPR/Cas9 Tool

“…Oxalic acid is the main acidic metabolite in S. rolfsi, and in many other fungi such as Sclerotinia sclerotiorum [12]. Oxalic acid is also reported to be directly toxic to plant tissue [13], for it is a strong acid among organic acids and is 10,000 times more acidic than acetic acid.…”

Changes in Anatomical Features and Protein Pattern of Sunflower Partially Resistant and Susceptible Lines During Infection By Virulence Factors of Sclerotinia Sclerotiorum

“…S. sclerotiorum infection induced changes in transcriptome and proteome levels in plant hosts [7][8][9][10][11][12]. The proteome-level study can convey us to identify the real molecules involved in plant defense responses [13].…”