The Location of the Chickpea Cell Wall ?V-Galactosidase Suggests Involvement in the Transition between Cell Proliferation and Cell Elongation

We report the generation of antibodies against a ?-galactosidase (?V-Gal) from Cicer arietinum and the subsequent immunolocalization of the protein in different parts and developmental stages of the plant. ?V-Gal is a cell wall protein encoded by the CanBGal-5 gene, which belongs to a family of at least four ?-galactosidase genes in chickpea. We have previously reported that CanBGal-5 transcripts are located in organs with high elongation and cell division rates, such as meristematic hooks, very young epicotyls, and apical internodes. ?V-Gal protein is the only studied chickpea ?-galactosidase widely present in meristematic hooks, mainly in the meristematic apical zone. These results agree with the previously reported transcription pattern of CanBGal-5 and may reflect its involvement in cell wall modifications during the final stages of cell proliferation, leading to the establishment of an expanding cell wall. The location of ?V-Gal in the cell wall of procambium cells and in pericycle cells of the developing lateral roots also supports the involvement of ?V-Gal in this process. During seedling and plant growth, the highest levels of bV-Gal protein were detected in the youngest actively growing epicotyls and in the apical growing internodes. Thus, protein levels pointed to a relationship between bV-Gal and the events occurring in the cell wall during the early stages of development. Immunolocalization studies in different zones of epicotyls and radicles suggest a role for ?V-Gal in cell elongation.

This work was supported by a grant from the Ministerio de Educaci?n y Ciencia, Spain (BFU2006-09786), and by a grant from the Junta de Castilla y Le?n (SA103A07).