ISOLATION OF PATHOGEN STRESS-INDUCIBLE CDNAS FROM ALFALFA BY MESSENGER-RNA DIFFERENTIAL DISPLAY/

Differential display of mRNA was used to isolate a full-length (SRG1) and a partial (SRG2) alfalfa cDNA induced during infection with the fu ngal pathogen Colletotrichum trifolii. The deduced amino acid sequence s are similar to each other and resemble plant defense-related protein s and tree pollen allergens. SRG1 is a member of a gene family in alfa lfa, which may also include the putative defense-related gene PR10. Un like many defense-related genes described in similar systems, expressi on of SRG1-like genes does not correlate with resistance to C. trifoli i. We speculate SRG1 is induced in response to plant stress.