An α-galactosidase with an essential function during leaf development

Abstract

The putative alpha-galactosidase gene HvSF11 of barley, previously shown to be expressed during dark induced senescence, is expressed in the growing/elongating zone of primary foliage leaves of barley. The amino acid sequence deduced from the full length HvSF11 cDNA contains a hydrophobic signal sequence at the N-terminus. Phylogenetic relationship of the HvSF11 encoded barley alpha-galactosidase to other alpha-galactosidases revealed high homology with the alpha-galactosidase encoded by the gene At5g08370 from Arabidopsis thaliana. We have isolated two independent heterozygous At5g08370 T-DNA insertion mutants from Arabidopsis thaliana, both of which have a higher number of rosette leaves with a curly surface leaf morphology and delayed flowering time in comparison to wildtype plants. Localization of the Arabidopsis alpha-galactosidase protein via GUS-tag revealed that the protein is associated with the cell wall. This result was confirmed by immunological detection of the orthologous barley protein in a protein fraction derived from cell walls of barley leaves. It is concluded that the alpha-galactosidase proteins from barley and Arabidopsis might fulfill an important role in leaf development by functioning in cell wall loosening and cell wall expansion.

Verticillium longisporum Infection Affects the Leaf Apoplastic Proteome, Metabolome, and Cell Wall Properties in Arabidopsis thaliana

“…AGAL2 functions in leaf development [70]. Heterozygous T-DNA insertion lines with reduced AGAL2 levels displayed curly leaves pointing to a role of AGAL2 in cell wall loosening [70].…”

Catalytic Mechanism of Human α-Galactosidase

“…digestion, lysosomal degradation, ER-associated degradation, and biosynthesis), potent inhibitors of glycosidases are valuable commercial and research products (49). Inhibitors of clan D glycosidases would have broad applications, including, for example, modulating leaf development in plants (50), seed germination in legumes (51), and substrate reduction therapy in galactosemia (52).…”

Functional Characterization of a Eukaryotic Melibiose Transporter

“…On the other hand, numerous cell wall-localized a-galactosidases that might hydrolyze these molecules in the apoplast were identified from different plant species (Feurtado et al, 2001;Pennycooke et al, 2003;Chrost et al, 2007). Together with the growth analyses mentioned above, this might indicate that, unlike Suc, raffinose and melibiose typically are intracellular carbohydrates and not intentionally released into the plant apoplast for the supply of adjacent cells or tissues.…”