Cloning of a Cicer arietinum β-Galactosidase with Pectin-Degrading Function

Abstract

The cDNA clone (CanBGal-3) encoding a cell wall pectin-degrading b-galactosidase (bIII-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 b-galactosidase clones with the purified bIII-Gal protein sequence. The expression pattern of the gene corresponding to CanBGal-3 was in concordance with the fluctuations of the enzyme bIII-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 b-galactosidase encoded by this clone is a pectin-degrading enzyme. The authors propose an important role for chickpea bIII-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.

In vivo Expression of a Cicer arietinum β-galactosidase in Potato Tubers Leads to a Reduction of the Galactan Side-chains in Cell Wall Pectin

“…4). This result allows us to confirm that the pectin-degrading activity of the chickpea βIII-Gal reported in vitro against epicotyl cell walls (Esteban et al 2003) also occurs in vivo and in other dicotyledoneous cell walls.…”

“…This enzyme was characterized as a protein involved in the cell wall autolytic process (Dopico et al 1990a, Dopico et al 1990b, Dopico et al 1990c). The cDNA CanBGal-3, which encodes this protein, has been previously identified among several cDNAs encoding β-galactosidases (Esteban et al 2003) and here we confirm that CanBGal-3 encodes a pectin-degrading enzyme.…”

Carbohydrate-Active Enzymes Involved in the Secondary Cell Wall Biogenesis in Hybrid Aspen

“…It is thus likely that all plant homologs are b-galactosidases. In plants, these enzymes form a multigene family with 18 copies in Arabidopsis, and the characterized members act on various substrates, including arabinogalactans, galactolipids, and pectin to release Gal (Smith and Gross, 2000;Esteban et al, 2003). A particular feature of plant GT35 members is that about one-half of them carry a C-terminal extension distantly related to animal rhamnose-binding lectins, suggesting that this extension is a carbohydrate-binding module.…”

Galactose metabolism in cell walls of opening and senescing petunia petals

“…They exhibit activity against preparations of pectic cell wall polysaccharides, presumably by degrading (1!4)--galactan side chains of pectin (e.g. Dopico et al 1990;De Veau et al 1993;Carey et al 1995Carey et al , 2001Smith and Gross 2000;Esteban et al 2003). -Galactosidases are encoded by multigene families in plants (e.g.…”

“…In tomato, a family of sevengalactosidases exhibit diVerential expression in developing and ripening fruit (Smith and Gross 2000). In chickpea epicotyls, members of the -galactosidase gene family appear to have quite diVerent roles in the young and adult plant (Esteban et al 2003Martín et al 2005).…”