Pathogenesis-related protein explained

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.

Many pathogenesis-related protein families also coincide with groups of human allergens, even though the allergy may have nothing to do with the defense function of the proteins. Grouping these proteins by their sequence features allows for finding potential allergenic proteins from sequenced plant genomes, a field of study dubbed "allergenomics".^[5]

Classification

, 17 families of PR proteins have been named:^[6]

Different PR-protein families and allergens identified!Family!Domain classification!Proteins!Functions!Allergens

PR-1		PR-1 a, PR-1 b, and PR-1 c	Antifungal (CAP)	Cuc m 3 (muskmelon;)—oral allergy syndrome
PR-2	(GH17)	β-1,3-Glucanases	Cleaves β-1,3-glucans	Hev b 2 (latex;)—contact dermatitis Ole e 9 (olive)—respiratory allergy Mus a 5 (banana)—oral allergy syndrome
PR-3		Chitinase types I, II, IV, V, VI, and VII	Endochitinase	Pers a 1 (avocado)—itchy eyes or nose, asthma, swelling, and so forth. Mus a 2 (banana)—food allergy like swelling of lips, anaphylaxis, and so forth
PR-4		Barwin domain chitinase I/II	Antifungal and chitinase	Pro-heveins: Hev b 6—contact dermatitis
PR-5		Thaumatin-like	Antifungal	Jun a 3 (mountain cedar), Cry j 1 (Japanese cedar), and Cup a 3 (Arizona cypress)—rhinitis, conjunctivitis, and asthma Pru av 2 (cherry), Mal d 2 (apple), Cap a 1 (bell pepper), Act d 2 (kiwi), and Mus a 4 (banana)—oral allergy syndrome
PR-6		Potato protease I	Proteinase inhibitor
PR-7	(Subtilisin-like)	Tomato endoproteinase P69	Endoproteinase
PR-8	(GH18)	Cucumber chitinase	Chitinase III	Hevamine (latex,)—contact dermatitis. Ziz m 1 (Indian jujube,)—oral allergy syndrome Cof a 1 (coffee,)—eye and airway allergy
PR-9	(Haem peroxidase III)	Tobacco lignin-forming peroxidase	Peroxidase
PR-10		Parsley "PR-1"	Ribonuclease-like	Bet v 1 (birch pollen)— allergic rhinoconjunctivitis and asthma Pru av 1 (cherry), Mal  d  1 (apple), Api g 1 (celery), and Dau c 1 (carrot)—oral allergy syndrome Gly m 4 (soy), Vig r 1 (mung bean), Cor a 1 (hazelnut), and Cas s 1 (chestnut), Act c 8 (golden kiwi fruit), Act d 8 (green kiwi fruit) —oral allergy syndrome
PR-11	(GH18)	Tobacco chitinase V	Chitinase
PR-12		Radish Rs-AFP3	Plant Defensin
PR-13		Arabidopsis THI2.1	Thionin
PR-14		Lipid transfer proteins	Shuttling of phospholipids and fatty acids	Par j 1 (weed;)—rhinitis and asthma Pru p 3 (peach), Mal d 3 (apple), Pru av 3 (cherry), Pru ar 3 (apricot), Cor a 8 (hazelnut), Cas s 8 (chestnut), and Zea m 14 (maize)—oral allergy syndrome
PR-15		Barley OxOa	germin Oxalate oxidase
PR-16		Barley OxOLP	germin-like
PR-17		Tobacco NtPRp27	late blight resistance(?)^[7]

Identification

As PR proteins are produced when plant tissue is stressed, various ways of stress signaling is used to "bait" the plant into expressing PR genes for identification. Useful stressors include an actual infection or simply defense signals such as salicylate and methyl jasmonate. The proteins can be identified by isolation, peptide digestion, and matching against the genomic sequences (protein sequencing). The sequences obtained can then be checked against known PR protein families for categorization.^{[8] [9]}

See also

• Acibenzolar-S-methyl
• Glossary of phytopathology
• R gene, unrelated resistance proteins

Further reading

• Book: Muthukrishnan S, Datta SP . Pathogenesis-related proteins in plants . limited . CRC Press . Boca Raton . 1999 . 291 . 0-8493-0697-3 .
• Web site: Defense-Related Proteins of Higher Plants . dmd.nihs.go.jp.

External links

• WHO Allergen Nomenclature for conversion of allergens to specific sequences.
• UniProt keyword: KW-0568
• Gene ontology mapping: GO:0009607, GO:0006952

Notes and References

1. Loon LC . Pathogenesis-related proteins . Plant Molecular Biology . 1985 . 4 . 2–3 . 111–116 . 10.1007/BF02418757. 24310747 . 37281639 .
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 . Induction by Salicylic Acid of Pathogenesis-related Proteins and Resistance to Alfalfa Mosaic Virus Infection in Various Plant Species . Journal of General Virology . 67 . 1986 . 10 . 2135–2143 . 10.1099/0022-1317-67-10-2135 . free .
4. Waters EJ, Shirley NJ, Williams PJ . Nuisance Proteins of Wine Are Grape Pathogenesis-Related Proteins . Journal of Agricultural and Food Chemistry . 1996 . 44 . 1 . 3–5 . 10.1021/jf9505584 .
5. Di Girolamo . F . Muraca . M . Mazzina . O . Lante . I . Dahdah . L . Proteomic applications in food allergy: food allergenomics. . Current Opinion in Allergy and Clinical Immunology . June 2015 . 15 . 3 . 259–66 . 10.1097/ACI.0000000000000160 . 25899690. 751042 .
6. Sinha . Mau . Singh . Rashmi Prabha . Kushwaha . Gajraj Singh . Iqbal . Naseer . Singh . Avinash . Kaushik . Sanket . Kaur . Punit . Sharma . Sujata . Singh . Tej P. . Current Overview of Allergens of Plant Pathogenesis Related Protein Families . The Scientific World Journal . 2014 . 2014 . 543195 . 10.1155/2014/543195 . 24696647. 3947804 . free . This article contains quotations from this source, which is available under the Creative Commons Attribution 3.0 (CC BY 3.0) license.
7. Shi . X . Tian . Z . Liu . J . van der Vossen . EA . Xie . C . A potato pathogenesis-related protein gene, StPRp27, contributes to race-nonspecific resistance against Phytophthora infestans. . Molecular Biology Reports . February 2012 . 39 . 2 . 1909–16 . 10.1007/s11033-011-0937-5 . 21667110. 12384096 .
8. Elvira . M. I. . Galdeano . M. M. . Gilardi . P. . Garcia-Luque . I. . Serra . M. T. . Proteomic analysis of pathogenesis-related proteins (PRs) induced by compatible and incompatible interactions of pepper mild mottle virus (PMMoV) in Capsicum chinense L3 plants . Journal of Experimental Botany . 19 March 2008 . 59 . 6 . 1253–1265 . 10.1093/jxb/ern032. 18375936 . free . 10261/57734 . free .
9. Sabater-Jara . AB . Almagro . L . Belchí-Navarro . S . Barceló . AR . Pedreño . MA . Methyl jasmonate induces extracellular pathogenesis-related proteins in cell cultures of Capsicum chinense. . Plant Signaling & Behavior . March 2011 . 6 . 3 . 440–2 . 10.4161/psb.6.3.14451 . 21346408. 3142433 . 2011PlSiB...6..440S .