An α-galactosidase with an essential function during leaf development
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The putative α-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 α-galactosidase to other α-galactosidases revealed high homology with the α-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 α-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 α-galactosidase proteins from barley and Arabidopsis might fulfill an important role in leaf development by functioning in cell wall loosening and cell wall expansion.
Keywordsα-Galactosidase Hordeum vulgare Arabidopsis thaliana T-DNA insertion mutants Cell wall Cell growth
days after germination
Accession numbersHordeum vulgare Y13848 Arabidopsis thaliana BT000619
We are grateful for the excellent technical assistance of Annekatrin Daniel. We thank Dr. Maria Mulisch for her support with microscopy analysis. This work was partly supported by the German Research Foundation (DFG Kr1350/3-1).
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