Table 1.

Functions and Characteristics of Selected RLK/Pelle Family Members

Synonyma	Source	Subfamilyb	Tandem Clusterb	Gene Namec	Clade Ratiod	Funcate	Functions	Reference
BRI1/SR160	Arabidopsis/L. esculentum	LRR-Xb	no	At4g39400	1:1	D/R	Steroid hormone–mediated growth response	Li and Chory (1997); Searle et al. (2003)
SERK3/BAK1	Arabidopsis	LRR-II		At4g33430	3:2	D	Steroid hormone–mediated growth response	Hecht et al. (2001); Li et al. (2002); Nam and Li (2002)
CRINKLY4	Z. mays	CR4L	no	Osi005386.1	1:1	D	Epidermal cell development	Becraft et al. (1996)
EMS1/EXS	Arabidopsis	LRR-Xb	no	At5g07280	1:0	D	Microspore development	Canales et al. (2002); Zhao et al. (2002);
ERECTA	Arabidopsis	LRR-XIIIb	no	At2g26330	2:2	D	Organ initiation and elongation	Torii et al. (1996)
HAESA	Arabidopsis	LRR-XI	no	At4g28490	1:0	D	Delayed floral organ abscission	Jinn et al. (2000)
PRK1	Petunia inflata	LRR-III	no	Osi009992.1	1:1	D	Microspore development	Lee et al. (1996)
PSKR	D. carota	LRR-Xb	no	At2g02220	1:1	D	Phytosulfokine mediated growth response	Matsubayashi et al. (2002)
CLAVATA1/HAR1/NARK	Arabidopsis/Lotus japonicus/Glycine max	LRR-XI	no	At1g75820	1:1	D/S	Control of apical meristem proliferation in Arabidopsis, symbiotic interaction in the others	Clark et al. (1997); Krusell et al. (2002); Nishimura et al. (2002); Searle et al. (2003)
NORK/SYMRK	Medicago trunculata	LRR-Ic	no	At1g67720	1:0	S	Development of root nodule	Endre et al. (2002); Stracke et al. (2002)
NFR1/LYK3	L. japonicus/M. trunculata	LysM-I	no	Osi009166.2	1:2	S	Perception of Nod factor, infection thread formation	Limpens et al. (2003); Radutoiu et al. (2003)
LYK4f	M. trunculata	LysM-I	ND	ND	ND	S	Infection thread formation	Limpens et al. (2003)
NFR5/SYM10	L. japonicus/Pisum sativum	LysM-II	no	Osi015153.1	1:2	S	Perception of Nod factor	Madsen et al. (2003)
RKC1	Arabidopsis	DUF26-Ib	yes	At4g23250	37:0	R	Salicylic acid inducible	Ohtake et al. (2000)
RKL1	Arabidopsis	LRR-III	no	At1g48480	2:3	R	Salicylic acid inducible	Ohtake et al. (2000)
RKS1,2	Arabidopsis	SD-1a	yes	At1g11340-50	4:0	R	Salicylic acid inducible	Ohtake et al. (2000)
SFR1,2	Brassica oleracea	SD-1a	yes	At1g65790, At4g21380	4:1	R	Wound and bacterial inducible expression	Pastuglia et al. (1997)
FLS2	Arabidopsis	LRR-XII	no	At5g46330	1:1	R	Flagellin insensitivity	Gomez-Gomez and Boller (2000)
LRK10	Avena sativa	LRK10-L2	yes	Osi011907.3	0:23	R	Resistance to fungal pathogen	Feuillet et al. (1997)
PBS1	Arabidopsis	RLCK-VIIa	no	At5g13160	1:0	R	Resistance to bacterial pathogen	Swiderski and Innes (2001)
SIRK	Arabidopsis	LRR-Ia	yes	At2g19190	44:0	R	Upregulated during senescence and pathogen challenge	Robatzek and Somssich (2002)
WAK1	Arabidopsis	WAK	yes	At1g21210-50	6:4	R	Defense response	He et al. (1998)
Xa21	O. sativa	LRR-XII	yes	Osi009420.2	0:17	R	Resistance to bacterial pathogen	Song et al. (1995)

^aPotentially orthologous sequences from different species are separated by slashes.

^bTandem clustering and classification information can be found in Supplements A and C, respectively, online.

^cThe names for closest relatives in Arabidopsis or rice.

^dThe ratio between Arabidopsis and rice genes in the ancestral unit of the gene in question or its closest relative.

^eFuncat, functional categories: D, developmental control; S, symbiosis; R, resistance or defense responses.

^fLYK1, LYK4, LYK6, and LYK7 form a sister group to a LysM-I clade that contains both Arabidopsis and rice genes. Therefore, no potential orthologs from either Arabidopsis or rice can be assigned (ND, not determined).