GEPHE SUMMARY
Entry Status
Published
GepheID
GP00000681
Main curator
Martin
PHENOTYPIC CHANGE
Trait Category
Trait State in Taxon A
Arabidopsis thaliana- Col-0 and other lines
Trait State in Taxon B
Arabidopsis thaliana- Shahdara
Ancestral State
Taxon A
Taxonomic Status
Taxon A
Common Name
thale cress
Synonyms
thale cress; mouse-ear cress; thale-cress; Arabidopsis thaliana (L.) Heynh.; Arabidopsis thaliana (thale cress); Arabidopsis_thaliana; Arbisopsis thaliana; thale kress
Rank
species
Lineage
Show more ... ; Embryophyta; Tracheophyta; Euphyllophyta; Spermatophyta; Magnoliophyta; Mesangiospermae; eudicotyledons; Gunneridae; Pentapetalae; rosids; malvids; Brassicales; Brassicaceae; Camelineae; Arabidopsis
NCBI Taxonomy ID
is Taxon A an Infraspecies?
Yes
Taxon A Description
Arabidopsis thaliana- Col-0 and other lines
Taxon B
Common Name
thale cress
Synonyms
thale cress; mouse-ear cress; thale-cress; Arabidopsis thaliana (L.) Heynh.; Arabidopsis thaliana (thale cress); Arabidopsis_thaliana; Arbisopsis thaliana; thale kress
Rank
species
Lineage
Show more ... ; Embryophyta; Tracheophyta; Euphyllophyta; Spermatophyta; Magnoliophyta; Mesangiospermae; eudicotyledons; Gunneridae; Pentapetalae; rosids; malvids; Brassicales; Brassicaceae; Camelineae; Arabidopsis
NCBI Taxonomy ID
is Taxon B an Infraspecies?
Yes
Taxon B Description
Arabidopsis thaliana- Shahdara
GENOTYPIC CHANGE
Generic Gene Name
BGAL6
Synonyms
beta-galactosidase 6; BGAL6; MBK5.28; MBK5_28; MUCILAGE-MODIFIED 2; At5g63800
Sequence Similarities
Belongs to the glycosyl hydrolase 35 family.
UniProtKB
Arabidopsis thaliana
GenebankID or UniProtKB
Presumptive Null
Yes
Molecular Type
Aberration Type
Deletion Size
10-99 bp
Molecular Details of the Mutation
44bp deletion in exon 15; from Leu-662 onwards. This deletion causes a frame-shift mutation changing the next 23 amino acids followed by the introduction of a stop codon.
Experimental Evidence
Authors
Macquet A; Ralet MC; Loudet O; Kronenberger J; Mouille G; Marion-Poll A; North HM
Abstract
The Arabidopsis thaliana accession Shahdara was identified as a rare naturally occurring mutant that does not liberate seed mucilage on imbibition. The defective locus was found to be allelic to the mum2-1 and mum2-2 mutants. Map-based cloning showed that MUCILAGE-MODIFIED2 (MUM2) encodes the putative beta-D-galactosidase BGAL6. Activity assays demonstrated that one of four major beta-D-galactosidase activities present in developing siliques is absent in mum2 mutants. No difference was observed in seed coat epidermal cell structure between wild-type and mutant seed; however, weakening of the outer tangential cell wall by chemical treatment resulted in the release of mucilage from mum2 seed coat epidermal cells, and the mum2 mucilage only increased slightly in volume, relative to the wild type. Consistent with the absence of beta-D-galactosidase activity in the mutant, the inner layer of mucilage contained more Gal. The allocation of polysaccharides between the inner and outer mucilage layers was also modified in mum2. Mass spectrometry showed that rhamnogalacturonan I in mutant mucilage had more branching between rhamnose and hexose residues relative to the wild type. We conclude that the MUM2/BGAL6 beta-D-galactosidase is required for maturation of rhamnogalacturonan I in seed mucilage by the removal of galactose/galactan branches, resulting in increased swelling and extrusion of the mucilage on seed hydration.
Additional References
RELATED GEPHE
Related Genes
Related Haplotypes
4
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