Poster: Membrane Transport
Abs #
1238: A proton pump, AtAHA10, is required for proper flavanoid deposition in the developing seed coat of arabidopsis.
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Presenter: |
Baxter, Ivan R, ibaxter@scripps.edu | Authors | Baxter, Ivan R (A) Foster, Nathan (C) Armstrong, Gordon (C) Tchieu, Jason (B) Sussman, Michael (D) Boutry, Marc (E) Palmgren, Michael (F) Gribskov, Michael (B) Axelsen, Kristian (G) Harper, Jeffrey (A) Young, Jeffery (C) | | Affiliations: |
(A): The Scripps Research Institute
(B): U. Cal. San Diego
(C): Western Washington University
(D): U. of WIsconsin
(E): Universite Catholique de Louvain,Louvain-La-Neuve, Belgium
(F): The Royal Vetrinary and Agricultural University, Copenhagen, Denmark
(G): Swiss Institute of Bioinformatics, Geneva, Switzerland
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Ion pumps belonging to the P-type ATPases superfamily share a common enzymatic mechanism in which ATP hydrolysis is used to transport ions across a membrane. Using the recently completed rice genomic sequence, we compared the full complement of P-type ATPases between rice (a monocot) and Arabidopsis (a dicot). We found 23 clusters of genes which are conserved between the two species. T-DNA insertions in Arabidopsis are being used to identify functions of individual isoforms within different clusters. Here we report the characterization of AtAHA10, the only Arabidopsis member of H+ ATPase (proton pump) cluster 3 (OsAHA9 is the only rice member). AtAHA10 appears to be primarily expressed in the inner integument of developing seeds. Seeds from T-DNA insertion mutants, homozygous at the AtAHA10 locus, show a transparent-testa (tt) like phenotype. Segregation analysis suggests that the lesion is in maternal tissue rather than the developing embryo. Transparent-testa mutants have reduced levels of the flavanoids that give wild-type seeds their brown color and confer seed coat integrity. Seeds from Ataha10 (-/-) plants also appear to have seed coat integrity deficiencies as shown by decreases in seed weight over time (compared to wt) and changes in the control of dormancy. Previously identified tt mutants include proteins in the flavanoid biosynthesis pathway and putative multidrug-secondary transporters. The mechanism by which AHA10, a primary transporter, selectively affects flavanoid biosynthesis or transport pathways is unknown.
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