CYTOLOGICAL LOCALIZATION OF THE PGIP GENES IN THE EMBRYO SUSPENSOR CELLS OF PHASEOLUS-VULGARIS L

Polygalacturonase-inhibiting protein (PGIP) is a cell wall protein whi ch inhibits fungal endopolygalacturonases. A small gene family encodes PGIP in the genome of common bean, as indicated by Southern-blot expe riments performed at high-stringency conditions. Southern-blot analysi s of DNA extracted from different cultivars of Phaseolus vulgaris and from Phaseolus coccineus showed length polymorphism of the hybridizing restriction fragments. The cytological localization of the PGIP genes was determined in polytene chromosomes of the P. vulgaris embryo susp ensor cells. In-situ hybridization experiments using the cloned PGIP g ene revealed labelling over a single region of the pericentromeric het erochromatin of chromosome pair X. next to the euchromatin, suggesting that PGIP gene family may be clustered in one chromosomal region.