CDNA CLONING AND EXPRESSION OF POLYGALACTURONASE-INHIBITING PROTEINS (PGIPS) FROM RED RASPBERRY (RUBUS-IDAEUS)

Plant polygalacturonase-inhibiting proteins (PGIPs) inhibit endo-polyg alacturonases (endo-PGs) released by invasive fungi, Two potential PGI P cDNAs have been cloned from raspberry (Rubus idaeus). PGIP1 correspo nds to a full-length PGIP cDNA with a high degree of identity with pre viously isolated genes and maintains all the characteristic features o f PGIP peptides. A genomic fragment of PGIP1 identifies a single 243 b p intron which is efficiently spliced out of the PGIP1 pre-mRNA transc ript. PGIP2 contains a frame shift mutation which would lead to the lo ss of 105 amino acids off the C-terminus. Contrary to PGIP activity le vels in raspberry (Johnston et al., 1993), expression analysis detecte d PGIP1 at equal levels throughout fruit development from closed flowe r, through to ripe fruit.