Deactivation of gibberellin by 2-oxidation during germination of photoblastic lettuce seeds.
Gibberellin (GA) plays an important role in the induction of germination of photoblastic lettuce (Lactuca sativa L. cv. Grand Rapids) seeds. We have previously shown that gene expression of a GA 3-oxidase (Ls3h1) increased after a red light treatment, resulting in an increase in the endogenous content of GA1, bioactive GA. Since the metabolism of GAs is also important for determining the endogenous levels of bioactive GAs, cDNAs encoding GA 2-oxidases (LsGA2ox1 and LsGA2ox2, for L. sativa GA 2-oxidase), which catalyze the deactivation of GAs, were isolated from lettuce seeds to investigate the regulation of these genes by light. An expression analysis shows that the mRNA levels of both enzymes was not markedly altered under different light conditions during germination. However, the amount of LsGA2ox2 transcripts was decreased to approximately half the level by red light. This reduction might play a role in the increase in GA1 level by red light in the lettuce seeds.
Nakaminami
Kentaro
K
Course of the Science of Bioresources, The United Graduate School of Agricultural Science, Iwate University, Morioka, Japan.
Sawada
Yoshiaki
Y
Suzuki
Miwako
M
Kenmoku
Hiromichi
H
Kawaide
Hiroshi
H
Mitsuhashi
Wataru
W
Sassa
Takeshi
T
Inoue
Yasunori
Y
Kamiya
Yuji
Y
Toyomasu
Tomonobu
T
D000595:Amino Acid Sequence; D015139:Blotting, Southern; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D004789:Enzyme Activation; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D018525:Germination; D005875:Gibberellins / Q000235:genetics / Q000378:metabolism*; D018545:Lactuca / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D018076:DNA, Complementary; D005875:Gibberellins; D018749:RNA, Plant; D006899:Mixed Function Oxygenases; C121463:gibberellin 2-dioxygenase