Isolation of pathogen/stress-inducible cDNAs from alfalfa by mRNA 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 fungal pathogen Colletotrichum trifolii. The deduced amino acid sequences are similar to each other and resemble plant defense-related proteins and tree pollen allergens. SRG1 is a member of a gene family in alfalfa, which may also include the putative defense-related gene PR10. Unlike many defense-related genes described in similar systems, expression of SRG1-like genes does not correlate with resistance to C. trifolii. We speculate SRG1 is induced in response to plant stress.