Pathogenesis-related protein

Pathogenesis-related (PR) proteins are proteins produced in plants in the event of a pathogen attack.^[1] They are induced as part of systemic acquired resistance. Infections activate genes that produce PR proteins. Some of these proteins are antimicrobial, attacking molecules in the cell wall of a bacterium or fungus. Others may function as signals that spread “news” of the infection to nearby cells. Infections also stimulate the cross-linking of molecules in the cell wall and the deposition of lignin, responses that set up a local barricade that slows spread of the pathogen to other parts of the plant.^[2]

Salicylic acid plays a role in the resistance to pathogens by inducing the production of pathogenesis-related proteins.^[3]

Many proteins found in wine are grape pathogen-related proteins.^[4] Those include thaumatin-like proteins and chitinases.

Functions

• An important common function of most PRs is their antifungal effects
• Some PRs also exhibit antibacterial, insecticidal or antiviral action.
• Function as signals that spread “news” of the infection to nearby cells.
• Infections also stimulate the cross-linking of molecules in the cell wall and the deposition of lignin, responses that set up a local barricade that slows spread of the pathogen to other parts of the plant
• Chitinase activity
• Peroxidase, ribonuclease and lysozyme activities
• Their hydrolytic, proteinase-inhibitory and membrane-permeabilizing ability.
• They inactivate the proteins secreted by the parasites in the invaded plant tissues

See also

• Glossary of phytopathology

References

1. Loon LC (1985). "Pathogenesis-related proteins". Plant Molecular Biology 4 (2-3): 111–116. doi:10.1007/BF02418757.
2. Campbell, N.A. and Reece, J.B. (2005). Biology (7th ed). San Francisco: Benjamin Cummings.
3. Van Huijsduijnen RAMH, Alblas SW, De Rijk RH, Bol JF (1986). "Induction by Salicylic Acid of Pathogenesis-related Proteins and Resistance to Alfalfa Mosaic Virus Infection in Various Plant Species". Journal of General Virology 67 (10): 2135–2143. doi:10.1099/0022-1317-67-10-2135.
4. Waters EJ, Shirley NJ, Williams PJ (1996). "Nuisance Proteins of Wine Are Grape Pathogenesis-Related Proteins". Journal of Agricultural and Food Chemistry 44 (1): 3–5. doi:10.1021/jf9505584.

Further reading

• Muthukrishnan S, Datta SP (1999). Pathogenesis-related proteins in plants. Boca Raton: CRC Press. p. 291. ISBN 0-8493-0697-3.