Table 1. Known and Probable PRRs Involved in Plant Immunity.

Name	Family	Ligand	Plant	References
FLS2	LRR-RK	flg22	Arabidopsis	Gómez-Gómez and Boller (2000); Bauer et al. (2001)
FLS3	LRR-RK	flgII-28	Tomato	Hind et al. (2016)
EFR	LRR-RK	elf18	Arabidopsis	Kunze et al. (2004); Zipfel et al. (2006)
PEPR1/2	LRR-RK	Peps	Arabidopsis	Yamaguchi et al. (2006); Huffaker et al. (2006); Huffaker and Ryan (2007); Krol et al. (2010); Yamaguchi et al. (2010)
XA21	LRR-RK	RaxX21-sY	Rice	Pruitt et al. (2015)
DORN1	Lectin-RK	eATP	Arabidopsis	Choi et al. (2014)
LORE	Lectin-RK	LPS	Arabidopsis	Ranf et al. (2015)
WAK1	EGF-Like-RLK	OGs	Arabidopsis	Decreux and Messiaen (2005); Brutus et al. (2010)
XPS1	LRR-RK	xup25	Arabidopsis	Mott et al. (2016)
OsCERK1	LysM-RLK	Chitin	Rice	Shimizu et al. (2010)
CEBiP	LysM-RP	Chitin	Rice	Kaku et al. (2006)
LYM1/3	LysM-RP	PGNs	Arabidopsis	Willmann et al. (2011)
LYP4/6	LysM-RLP	PGNs/chitin	Rice	B. Liu et al. (2012)
RLP23	LRR-RP	nlp20	Arabidopsis	Bi et al. (2014); Albert et al. (2015)
NbCSPR	LRR-RP	csp22	N. benthamiana	Saur et al. (2016)
LeEix1	LRR RP	Eix	Tomato	Bar et al. (2010)
LeEix2	LRR-RP	Eix	Tomato	Ron and Avni (2004)
ReMax/RLP1	LRR-RLP	eMax	Arabidopsis	Jehle et al. (2013)
Ve1	LRR-RLP	Ave1	Tomato	de Jonge et al. (2012)
Cf-2	LRR-RLP	Avr2	Tomato	Dixon et al. (1996); Luderer at al. (2002)
Cf-4	LRR-RLP	Avr4	Tomato	Joosten et al. (1997); Thomas et al. (1997)
Cf-4E	LRR-RLP	Avr4E	Tomato	Takken et al. (1999); Westerink et al. (2004)
Cf-9	LRR-RLP	Avr9	Tomato	Van den Ackerveken et al. (1992); Jones et al. (1994)
Cf-5	LRR-RLP	Unknown	Tomato	Dixon et al. (1998)
RLP30	LRR-RLP	SCFE1	Arabidopsis	Wang et al. (2008); Zhang et al. (2013)
ELR	LRR-RLP	Elicitin	Potato	Du et al. (2015)

Known PRRs refer to genetically confirmed receptors whose binding to patterns has been biochemically demonstrated, whereas probable PRRs refer to likely receptors with genetically confirmed roles in pattern recognition, but for which direct binding to patterns remains to be shown.