DIFFERENTIAL ACCUMULATION OF PGIP (POLYGALACTURONASE-INHIBITING PROTEIN) MESSENGER-RNA IN 2 NEAR-ISOGENIC LINES OF PHASEOLUS-VULGARIS L UPON INFECTION WITH COLLETOTRICHUM-LINDEMUTHIANUM

Polygalacturonase-inhibiting protein (PGIP) is an extracellular leucin e-rich repeat (LRR) protein that binds to and inhibits the activity of fungal endopolygalacturonases. Accumulation of PGIP mRNA in near-isog enic lines of Phaseolus vulgaris differing only for a single gene (Are ) which confers resistance to the race gamma of Colletotrichum lindemu thianum was followed by Northern blot analysis. In the incompatible in teraction, approximately 40 h after inoculation and 4 h before the obs erved hypersensitive response, PGIP mRNA reached a level 20-fold highe r than the basal level and returned to basal levels by 68 h. In the co mpatible interaction, PGIP mRNA did not significantly increase during the first 68 h. An eight-fold induction over the basal level was obser ved 84 h after inoculation. Transcripts returned to basal levels by 10 0 h. These data indicate that an early and rapid pgip transcript accum ulation is associated with the hypersensitive response in bean C. lind emuthianum race gamma interactions. (C) 1996 Academic Press Limited