Reduced glutathione is a novel regulator of vernalization-induced bolting in the rosette plant Eustoma grandiflorum.
The transition from the vegetative rosette stage to the reproductive growth stage (bolting) in the rosette plant Eustoma grandiflorum has a strict requirement for vernalization, a treatment that causes oxidative stress. Since we have shown that reduced glutathione (GSH) and its biosynthesis are associated with bolting in another rosette plant Arabidopsis thaliana, we here investigated whether a similar mechanism governs the vernalization-induced bolting of E. grandiflorum. Addition of GSH or its precursor cysteine, instead of vernalization, induced bolting but other thiols, dithiothreitol and 2-mercaptoethanol, did not. The inductive effect of vernalization on bolting was nullified by addition of buthionine sulfoximine (BSO), an inhibitor of GSH synthesis, without decreasing the plant growth rate. BSO-mediated inhibition of bolting was reversed by addition of GSH but not by cysteine. These indicate that vernalization-induced bolting involves GSH biosynthesis and is specifically regulated by GSH. Plant GSH increased during the early vernalization period along with the activity of gamma-glutamylcysteine synthetase that catalyzes the first step of GSH biosynthesis, although there was little change in amounts of GSH precursor thiols, cysteine and gamma-glutamylcysteine. These findings strongly suggest that vernalization stimulates GSH synthesis and synthesized GSH specifically determines the bolting time of E. grandiflorum.
Yanagida
Mototsugu
M
RIBS Okayama (Research Institute for Biological Sciences, Okayama), 7549-1 Yoshikawa, Kayou-cho, Okayama, 716-1241 Japan.
Mino
Masanobu
M
Iwabuchi
Masaki
M
Ogawa
Ken'ichi
K
D019328:Buthionine Sulfoximine / Q000494:pharmacology; D003545:Cysteine / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D029965:Gentianaceae / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D005978:Glutathione / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology; D019803:Glutathione Disulfide / Q000378:metabolism / Q000494:pharmacology; D008027:Light; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D010775:Photic Stimulation; D017382:Reactive Oxygen Species / Q000378:metabolism; D012098:Reproduction / Q000502:physiology* / Q000528:radiation effects; D012621:Seasons; D013438:Sulfhydryl Compounds / Q000378:metabolism / Q000494:pharmacology; D013696:Temperature
D004791:Enzyme Inhibitors; D017382:Reactive Oxygen Species; D013438:Sulfhydryl Compounds; D019328:Buthionine Sulfoximine; D005978:Glutathione; D003545:Cysteine; D019803:Glutathione Disulfide