Isolation of a French bean (Phaseolus vulgaris L.) homolog to the beta-glucan elicitor-binding protein of soybean (Glycine max L.)

A high-affinity membrane-bound beta-glucan elicitor-binding protein has bee n purified from microsomal preparations of French bean (Phaseolus vulgaris L.) roots. A 5900-fold purification was achieved by affinity chromatography of functionally solubilized membrane proteins. The beta-glucan-binding pro tein had an apparent molecular mass of 78 kDa when subjected to SDS-PAGE. W estern blot analysis showed specific crossreactivity of this French bean pr otein with an antiserum raised against a synthetic peptide representing an internal 15 amino acid fragment of the beta-glucan-binding protein from soy bean. Northern blot analysis with a cDNA probe of the soybean beta-glucan-b inding protein gene revealed a crosshybridizing transcript of 2.4 kb in Fre nch bean. These results indicate that the beta-glucan-binding proteins of F rench bean and soybean are conserved homologs involved in beta-glucan elici tor recognition. (C) 1999 Elsevier Science B.V. All rights reserved.