symbiotically defective mutants ofLotus japonicus.
Mol Plant Microbe Interact 19:914– 923
Miya A, Albert P, Shinya T, Desaki Y, Ichimura K,
Shirasu K, Narusaka Y, Kawakami N, Kaku H,
Shibuya N (2007) CERK1, a LysM receptor kinase is
essential for chitin elicitor signaling inArabidopsis.
Proc Natl Acad Sci USA 104:19613– 19618
Mulligan JT, Long SR (1985) Induction of rhizobium
meliloti nodC expression by plant exudate requires
nodD. Proc Natl Acad Sci USA 82:6609– 6613
Murakami Y, Miwa H, Imaizumi-Anraku H, Kouchi H,
Downie JA, Kawaguchi M, Kawasaki S (2006)
Positional cloning identifiesLotus japonicusNSP2, a
putative transcription factor of the GRAS family
required for NIN and ENOD40 gene expression in
nodule initiation. DNA Res 13:255– 265
Murray JD, Muni RR, Torres-Jerez I, Tang Y, Allen S,
Andriankaja M, Li G, Laxmi A, Cheng X, Wen J,
Vaughan D, Schultze M, Sun J, Charpentier M,
Oldroyd G, Tadege M, Ratet P, Mysore KS, Chen R,
Udvardi MK (2011) Vapyrin a gene essential for
intracellular progression of arbuscular mycorrhizal
symbiosis is also essential for infection by rhizobia in
the nodule symbiosis ofMedicago truncatula. Plant J
65:244– 252
Nakagawa T, Kaku H, Shimoda Y, Sugiyama A, Shi-
mamura M, Takanashi K, Yazaki K, Aoki T, Shibuya
N, Kouchi H (2011) From defense to symbiosis:
limited alterations in the kinase domain of LysM
receptor-like kinases are crucial for evolution of
legume-rhizobium symbiosis. Plant J 65:169– 180
Oldroyd GE, Long SR (2003) Identification and charac-
terization of nodulation-signaling pathway 2, a gene of
Medicago truncatulainvolved in nod actor signaling.
Plant Physiol 131:1027– 1032
Oldroyd GE, Murray JD, Poole PS, Downie JA (2011)
The rules of engagement in the legume-rhizobial
symbiosis. Annu Rev Genet 45:119– 144
Peters NK, Frost JW, Long SR (1986) A plantflavone
luteolin induces expression of rhizobium-meliloti
nodulation genes. Science 233:977– 980
Pumplin N, Mondo SJ, Topp S, Starker CG, Gantt JS,
Harrison MJ (2010)Medicago truncatulavapyrin is a
novel protein required for arbuscular mycorrhizal
symbiosis. Plant J 61:482– 494
Radutoiu S, Madsen LH, Madsen EB, Felle HH, Ume-
hara Y, Gronlund M, Sato S, Nakamura Y, Tabata S,
Sandal N, Stougaard J (2003) Plant recognition of
symbiotic bacteria requires two LysM receptor-like
kinases. Nature 425:585– 592
Radutoiu S, Madsen LH, Madsen EB, Jurkiewicz A, Fukai
E, Quistgaard EM, Albrektsen AS, James EK, Thirup
S, Stougaard J (2007) LysM domains mediate lipoch-
itin-oligosaccharide recognition and Nfr genes extend
the symbiotic host range. EMBO J 26:3923– 3935
Reddy DMR, Schorderet S, Feller U, Reinhardt D (2007)
A petunia mutant affected in intracellular accommo-
dation and morphogenesis of arbuscular mycorrhizal
fungi. Plant J 51:739– 750
Riely BK, Lougnon G, Ane JM, Cook DR (2007) The
symbiotic ion channel homolog DMI1 is localized in
the nuclear membrane ofMedicago truncatularoots.
Plant J 49:208– 216
Rodpothong P, Sullivan JT, Songsrirote K, Sumpton D,
Cheung KW, Thomas-Oates J, Radutoiu S, Stougaard
J, Ronson CW (2009) Nodulation gene mutants of
Mesorhizobium lotiR7A-nodZ and nolL mutants have
host-specific phenotypes onLotusspp. Mol Plant
Microbe Interact 22:1546– 1554
Routray P, Miller JB, Du L, Oldroyd G, Poovaiah BW
(2013) Phosphorylation of S344 in the calmodulin-
binding domain negatively affects CCaMK function
during bacterial and fungal symbioses. Plant J 76
(2):287– 296
Sacchettini JC, Baum LG, Brewer CF (2001) Multivalent
protein-carbohydrate interactions. A new paradigm for
supermolecular assembly and signal transduction.
Biochemistry 40:3009– 3015
Saito K, Yoshikawa M, Yano K, Miwa H, Uchida H,
Asamizu E, Sato S, Tabata S, Imaizumi-Anraku H,
Umehara Y, Kouchi H, Murooka Y, Szczyglowski K,
Downie JA, Parniske M, Hayashi M, Kawaguchi M
(2007) NUCLEOPORIN85 is required for calcium
spiking fungal and bacterial symbioses and seed
production inLotus japonicus. Plant Cell 19:610– 624
Sanchez-Vallet A, Saleem-Batcha R, Kombrink A, Han-
sen G, Valkenburg DJ, Thomma BP, Mesters JR
(2013) Fungal effector Ecp6 outcompetes host
immune receptor for chitin binding through intrachain
LysM dimerization. Elife 2:e00790
Sathyanarayanan PV, Cremo CR, Poovaiah BW (2000)
Plant Chimeric Ca2+/Calmodulin-dependent Protein
Kinase: role of the neural visinin-like domain in
regulating autophosphorylation and calmodulin affin-
ity. J Biol Chem 275:30417– 30422
Schauser L, Roussis A, Stiller J, Stougaard J (1999) A
plant regulator controlling development of symbiotic
root nodules. Nature 402:191– 195
Schlaman HR, Horvath B, Vijgenboom E, Okker RJ,
Lugtenberg BJ (1991) Suppression of nodulation gene
expression in bacteroids of rhizobium leguminosarum
biovar viciae. J Bacteriol 173:4277– 4287
Sieberer BJ, Chabaud M, Timmers AC, Monin A,
Fournier J, Barker DG (2009) A nuclear-targeted
cameleon demonstrates intranuclear Ca2+spiking in
Medicago truncatularoot hairs in response to rhizo-
bial nodulation factors. Plant Physiol 151:1197– 1206
Sieberer BJ, Chabaud M, Fournier J, Timmers AC, Barker
DG (2012) A switch in Ca2+spiking signature is
concomitant with endosymbiotic microbe entry into
cortical root cells ofMedicago truncatula. Plant J
69:822– 830
Singh S, Parniske M (2012) Activation of calcium- and
calmodulin-dependent protein kinase (CCaMK), the
central regulator of plant root endosymbiosis. Curr
Opin Plant Biol 15:444– 453
Singh S, Katzer K, Lambert J, Cerri M, Parniske M
(2014) CYCLOPS, a DNA binding transcriptional70 A. Binder et al.