Molecular Characterization of Disease-Resistance Response Gene DRR206-d from Pisum sativum (L.)

Abstract

The nonhost DRR in plants is associated with the rapid production of a number of proteins, many of which are likely to be involved in preventing a successful pathogen attack. We have previously described the isolation of a number of cDNA clones representing DRR transcripts that rapidly accumulate after inoculation of pea (Pisum sativum (L.)) pod tissue with spores of the bean pathogen Fusarium solani f. sp. phaseoli (Riggelman et al., 1985). Expression of one of these clones, pI206 (DRR206-a), was shown by northern analysis to be induced to high, sustained levels very early in the successful resistance response to F. solani f. sp. phaseoli, but expressed only transiently to low levels in the unsuccessful resistance response to the pea pathogen Fusarium solani f. sp. pisi. A preliminary western analysis with rabbit polyclonal antibodies directed against the DRR206 protein indicates that a protein with an apparent molecular mas of approximately 23,000 D is induced in pea pod tissue in response to challenge with F. solani f. sp. phaseoli. The nucleotide sequence of the genomic clone DRR206-d reported here is identical to the pI206 (DRR206-a) cDNA clone sequence (Fristensky et al., 1988) with the exception of a single conservative change in the coding region (base position 1836) and five base differences in the 3' untrans- lated region. These differences are most likely due to allelic variation resulting from the use of different pea cultivars to isolate the cDNA and genomic clones (Dot versus Alcan, respectively).