Fig. 2

Functional analysis of chimeric receptors in L. japonicus can provide information on constitutive dimerization of LysM protein ectodomains (EDs). Indicated chimeric proteins were expressed in roots of ecotype MG-20 and Nod factor receptor gene mutants. A co-transformed NINp-GUS construct allowed visualization of receptor-dependent activation of NIN expression. Three weeks after transformation, roots were treated with sterile water, 1 μM chitoheptaose [(GluNAc)₇] or 10 μg/mL chitin for 4 h and finally stained for GUS activity. a Roots expressing the single hybrid protein LYK4^ED–NFR5^ID did not show GUS activity. b Blue coloration was observed when the proteins LYK4^ED–NFR1^ID and LYK4^ED–NFR5^ID were co-expressed. c Analysis of LYK5^ED–NFR1^ID combined with LYK4^ED–NFR5^ID also resulted in blue-colored roots. Bars = 0.8 cm