Proteomics of Arabidopsis seed germination. A comparative study of wild-type and gibberellin-deficient seeds.
We examined the role of gibberellins (GAs) in germination of Arabidopsis seeds by a proteomic approach. For that purpose, we used two systems. The first system consisted of seeds of the GA-deficient ga1 mutant, and the second corresponded to wild-type seeds incubated in paclobutrazol, a specific GA biosynthesis inhibitor. With both systems, radicle protrusion was strictly dependent on exogenous GAs. The proteomic analysis indicated that GAs do not participate in many processes involved in germination sensu stricto (prior to radicle protrusion), as, for example, the initial mobilization of seed protein and lipid reserves. Out of 46 protein changes detected during germination sensu stricto (1 d of incubation on water), only one, corresponding to the cytoskeleton component alpha-2,4 tubulin, appeared to depend on the action of GAs. An increase in this protein spot was noted for the wild-type seeds but not for the ga1 seeds incubated for 1 d on water. In contrast, GAs appeared to be involved, directly or indirectly, in controlling the abundance of several proteins associated with radicle protrusion. This is the case for two isoforms of S-adenosyl-methionine (Ado-Met) synthetase, which catalyzes the formation of Ado-Met from Met and ATP. Owing to the housekeeping functions of Ado-Met, this event is presumably required for germination and seedling establishment, and might represent a major metabolic control of seedling establishment. GAs can also play a role in controlling the abundance of a beta-glucosidase, which might be involved in the embryo cell wall loosening needed for cell elongation and radicle extension.
Gallardo
Karine
K
Laboratoire Mixte Centre National de la Recherche Scientifique-Institut National de la Recherche Agronomique-Aventis, Aventis CropScience, B.P. 9163 F69263 Lyon cedex 09, France.
Job
Claudette
C
Groot
Steven P C
SP
Puype
Magda
M
Demol
Hans
H
Vandekerckhove
Joël
J
Job
Dominique
D
D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism; D001693:Biological Transport, Active; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D003598:Cytoskeletal Proteins / Q000187:drug effects / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D018525:Germination / Q000187:drug effects*; D005875:Gibberellins / Q000494:pharmacology*; D013058:Mass Spectrometry; D008716:Methionine Adenosyltransferase / Q000187:drug effects / Q000378:metabolism; D009154:Mutation; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D020543:Proteome / Q000187:drug effects / Q000378:metabolism*; D012639:Seeds / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D014230:Triazoles / Q000494:pharmacology; D014404:Tubulin / Q000187:drug effects / Q000378:metabolism; D001617:beta-Glucosidase / Q000187:drug effects / Q000378:metabolism
D029681:Arabidopsis Proteins; D003598:Cytoskeletal Proteins; D005875:Gibberellins; D020543:Proteome; D014230:Triazoles; D014404:Tubulin; C053370:paclobutrazol; D008716:Methionine Adenosyltransferase; D001617:beta-Glucosidase