Vacuolar H(+)-ATPase is expressed in response to gibberellin during tomato seed germination.
Completion of germination (radicle emergence) by gibberellin (GA)-deficient (gib-1) mutant tomato (Lycopersicon esculentum Mill.) seeds is dependent upon exogenous GA, because weakening of the endosperm tissue enclosing the radicle tip requires GA. To investigate genes that may be involved in endosperm weakening or embryo growth, differential cDNA display was used to identify mRNAs differentially expressed in gib-1 seeds imbibed in the presence or absence of GA(4+7). Among these was a GA-responsive mRNA encoding the 16-kD hydrophobic subunit c of the V(0) membrane sector of vacuolar H(+)-translocating ATPases (V-ATPase), which we termed LVA-P1. LVA-P1 mRNA expression in gib-1 seeds was dependent on GA and was particularly abundant in the micropylar region prior to radicle emergence. Both GA dependence and tissue localization of LVA-P1 mRNA expression were confirmed directly in individual gib-1 seeds using tissue printing. LVA-P1 mRNA was also expressed in wild-type seeds during development and germination, independent of exogenous GA. Specific antisera detected protein subunits A and B of the cytoplasmic V(1) sector of the V-ATPase holoenzyme complex in gib-1 seeds only in the presence of GA, and expression was localized to the micropylar region. The results suggest that V-ATPase plays a role in GA-regulated germination of tomato seeds.
Cooley
M B
MB
Department of Vegetable Crops, One Shields Avenue, University of California, Davis, California 95616-8631, USA.
Yang
H
H
Dahal
P
P
Mella
R A
RA
Downie
A B
AB
Haigh
A M
AM
Bradford
K J
KJ
D000595:Amino Acid Sequence; D001483:Base Sequence; D018076:DNA, Complementary; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000502:physiology*; D015723:Gene Library; D005875:Gibberellins / Q000494:pharmacology*; D018551:Solanum lycopersicum / Q000201:enzymology / Q000235:genetics* / Q000502:physiology; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009154:Mutation; D010937:Plant Growth Regulators / Q000494:pharmacology* / Q000502:physiology; D006180:Proton-Translocating ATPases / Q000737:chemistry / Q000235:genetics*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D012639:Seeds / Q000502:physiology; D025262:Vacuolar Proton-Translocating ATPases
D018076:DNA, Complementary; D005875:Gibberellins; D046911:Macromolecular Substances; D010937:Plant Growth Regulators; D011994:Recombinant Proteins; C007842:gibberellic acid; D025262:Vacuolar Proton-Translocating ATPases; D006180:Proton-Translocating ATPases