Table 1.

Summary of PR gene families and their functions

PR gene class	Common name	Function	References
PR-1	None (CAP/SCP superfamily)	Unknown.	[10, 11, 56]
PR-2	β-1,3-glucanase	Aid in cell wall degradation.	[10, 11, 79]
PR-3	Chitinase–type I, II, IV, V, VI, VII	Aid in cell wall degradation.	[10, 11, 80, 81]
PR-4	Chitinase-Hevein-like	Aid in cell wall degradation. May have RNase and DNase activity.	[10, 11, 19, 80–83]
PR-5	Thaumatin-like	Degrade pathogen membranes.	[10, 11, 42, 84, 85]
PR-6	Proteinase-inhibitor	Inhibit proteolysis by herbivorous insects.	[10, 11, 42, 86]
PR-7	Endoproteinase	Aid in cell wall degradation.	[10, 11, 87]
PR-8	Chitinase-type III	Aid in cell wall degradation. May have lysozymal activity.	[10, 11, 80, 81, 88]
PR-9	Peroxidase	Regulate reactive oxygen species concentration, contribute to cell wall lignification.	[10, 11, 89]
PR-10	Ribonuclease-like	Degrade RNA, may degrade viruses.	[10, 11, 90, 91]
PR-11	Chitinase-type I	Aid in cell wall degradation.	[10, 11, 80, 81]
PR-12	Defensin	Degrade fungal membranes.	[10, 11, 92]
PR-13	Thionin	Directly permeabilize lipid bilayers.	[10, 11, 61]
PR-14	Lipid-transfer Protein	Degrade pathogen membranes, mechanism unclear.	[10, 11, 93]
PR-15	Germin/Oxalate Oxidase	Regulate reactive oxygen species production.	[11, 62, 94]
PR-16	Germin-like/Oxalate Oxidase-like	Regulate reactive oxygen species production, catalyze monosaccharides.	[11, 62, 94]
PR-17	Putative Zinc-metalloproteinase	Proteinase function probable, mechanism unclear.	[11, 95]