title: The endogenous level of GA(1) is upregulated by high temperature during stem elongation in lettuce through LsGA3ox1 expression.
abstract: Bolting of lettuce is promoted by high temperatures. Gibberellins (GAs) play an important role in the bolting of several plant species, and it has been reported that exogenous GAs induce bolting and early flowering in lettuce. To clarify the role of GAs in this process, we examined the expression of genes involved in GA metabolism (LsGA20ox-1 and -2, LsGA3ox-1 and -2, and LsGA2ox-1 and -2) and endogenous GAs in lettuce stems. Quantitative reverse-transcription PCR indicated that the expression of a GA 3-oxidase gene, LsGA3ox1, is significantly upregulated by high (35/25 degrees C) temperature compared to low (25/15 degrees C) temperature, whereas transcription of the GA 20-oxidase gene, which is upregulated in long-day conditions in arabidopsis and spinach during bolting, is not clearly affected. Quantification of GA by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) showed that high temperature also upregulates the content of GA(1), a bioactive GA in lettuce. Our results suggest that LsGA3ox1 is a candidate for the gene responsible for the increase in GA(1) during lettuce bolting at high temperatures.
authors: National Institute of Vegetable and Tea Science, National Agriculture and Food Research Organization, Ano, Mie 514-2392, Japan. fukudama@affrc.go.jp
authors: Machiko
authors: M
authors: Fukuda
authors: Satoshi
authors: S
authors: Matsuo
authors: Kaori
authors: K
authors: Kikuchi
authors: Wataru
authors: W
authors: Mitsuhashi
authors: Tomonobu
authors: T
authors: Toyomasu
authors: Ichiro
authors: I
authors: Honda
mesh_terms: D005875:Gibberellins / Q000378:metabolism*; D006358:Hot Temperature; D018545:Lactuca / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018547:Plant Stems / Q000378:metabolism
chemical_list: D005875:Gibberellins; D010940:Plant Proteins; D006899:Mixed Function Oxygenases