Molecular mechanism of oxalic acid synthesis as virulence factor of Sclerotinia sclerotiorum

• Published in: Physiological and molecular plant pathology 2024-11, Vol.134, p.102412, Article 102412
• Main Authors: Daniel, Augustine Innalegwu, Basson, Gerhard, Keyster, Marshall, Klein, Ashwil, Gokul, Arun
• Format: Article
• Language: English
• Subjects: ascospores; cell walls; fungi; genes; Glyoxylate cycle; Oxalic acid; pathogenesis; pathogens; Phytopathogens; plant pathology; polygalacturonase; Reactive oxygen species; sclerotia; Sclerotinia sclerotiorum; secretion; species; Tricarboxylic acid cycle; virulence
• ISSN: 0885-5765
• DOI: 10.1016/j.pmpp.2024.102412

Sclerotinia sclerotiorum (Lib.) de Bary is a fungus with a wide variety of hosts that infects different plant species and causes major reductions in crop yields globally. Although it is a well-known pathogen, its life cycle is simple and involves either basal infection from myceliogenically germinated sclerotia or aerial infection from ascospores of carpogenically germinated sclerotia. Oxalic acid plays a major role in the pathogenesis of fungi; it lowers the pH of its environment and creates a favorable condition for infection. The secretion of enzymes that degrade the cell wall, oxalic acid, and effector proteins are essential virulence factors required for the successful pathogenesis of S. sclerotiorum. However, the specific molecular mechanisms underlying the pathogenesis of the fungi are still uncertain and continue to be the subject of ongoing research. It has been shown that oxalic acid has a direct effect on expression and activity of endopolygalacturonase SSPG1 at acidic pH. For instance, at low pH, there is an increase in the activity of polygalacturonase gene particularly Sspg1. This knowledge has provided a key point in the regulation of oxalic acid synthesis to control the virulence of this pathogen. •Sclerotinia sclerotiorum is a phytopathogen that affects a wide range of crops.•The virulence of the fungi is attributed to its ability to produce oxalic acid.•Oxalic acid is responsible for its virulence causing infection in plants.•Molecular studies have highlighted the significance of oxalic acid during different pathogenesis stages of the fungi.