Role of oxalic acid in the Sclerotinia wilt of sunflower

Oxalic Acid/Oxalates in Plants:From Self-Defence to Phytoremediation

“…Fungi such as Sclerotium rolfsii Sacc 26 and Sclerotinia sclerotiorum 27 secrete oxalic acid to infect the plants. Oxalic acid acts as a signalling molecule to induce a genetically regulated apoptotic-like programmed cell death (PCD) in host plant tissue 28 .…”

Comparative in vitro and in planta analyses of extracellular enzymes secreted by the pathogenic fungus Sclerotinia sclerotiorum

“…The culture supplemented with citrus pectin presented the highest acidification (2.8; Figure 2). The acidification of the culture medium likely occurred owing to the secretion of oxalic acid, an important factor in S. sclerotiorum pathogenesis (Noyes and Hancock, 1981;Marciano et al, 1983;Magro et al, 1984;Godoy et al, 1990;Cessna et al, 2000;Rollins and Dickman, 2001;Billon-Grand et al, 2012;Bueno et al, 2012). Oxalic acid produced by S. sclerotiorum has been suggested to control the spatial pattern of cell wall-degrading enzyme production during pathogenesis (Marciano et al, 1983;Godoy et al, 1990).…”

“…During interaction with its host, S. sclerotiorum secretes oxalic acid (Noyes and Hancock, 1981;Marciano et al, 1983;Magro et al, 1984;Cessna et al, 2000;Billon-Grand et al, 2012) and multiple lytic enzymes -pectinases, β-1,3-glucanases, glucosidases, cellulases, xylanases, and proteases -that facilitate penetration, colonization, and maceration of plant tissues to generate assimilable nutrients for fungal growth (Marciano et al, 1983;Godoy et al, 1990;Cessna et al, 2000). A wide range of activities are attributed to these enzymes, from enzymatic cleavage of structural host cell wall polysaccharides, in which the integrity of the cell wall barrier to pathogen entry is compromised, to more complex roles within the sphere of host-pathogen interactions, such as the release of oligosaccharides that function as elicitors of plant defense responses (Cooper, 1983;Côtè and Hahn, 1994;De Lorenzo et al, 1994.…”

Case Study: Sclerotinia sclerotiorum: Genetic Diversity and Disease Control

“…During the interaction with its host, S. sclerotiorum secretes a full complement of CWDEs, including pectinases, β-1,3-glucanases, glycosidases, cellulases, xylanases, and cutinases, which can facilitate penetration, macerate tissues, and degrade plant cell-wall components (Riou et al, 1991). Variation in pathogenicity has been associated with the production of pectolytic enzymes (Hancock, 1966;Lumsden, 1976Lumsden, , 1979Errampalli and Kohn, 1995), cellulase (Lumsden, 1969), hemicellulase, phosphotidase (Maxwell and Lumsden, 1970), and oxalic acid (Noyes and Hancock, 1981;Marciano et al, 1983;Cessna et al, 2000). That oxalic acid is a necessary pathogenicity factor was shown by Godoy et al (1990), who demonstrated that oxalic aciddeficient mutants were non-pathogenic.…”