The cDNA clone (CanBGal-3) encoding a cell wall pectin-
degrading -galactosidase ( III-Gal) from Cicer arietinum
L. cv. Castellana has been identified. The identification
was carried out by comparing the deduced amino acid
sequences of several isolated chickpea -galactosidase
clones with the purified III-Gal protein sequence. The
expression pattern of the gene corresponding to CanBGal-3
was in concordance with the fluctuations of the enzyme
III-Gal in different seedling organs, being specific to elongating
organs such as epicotyls and roots. Transformation
of Solanum tuberosum plants with the chickpea CanBGal-3
clone indicated that the -galactosidase encoded by this
clone is a pectin-degrading enzyme. The authors propose an
important role for chickpea III-Gal in pectin degradation
in cell walls of vegetative organs such as epicotyls and roots.
The degradation of galactan carried out by this enzyme
may determine structural changes and affect cell wall
porosity. It is suggested that the increase in the size of cell
wall pores could permit access of other cell wall-modifying
enzymes to their substrate.
