共查询到20条相似文献,搜索用时 31 毫秒
1.
Gibberellins: regulating genes and germination 总被引:14,自引:1,他引:13
2.
3.
A Mak-like kinase is a repressor of GAMYB in barley aleurone 总被引:8,自引:0,他引:8
Woodger FJ Gubler F Pogson BJ Jacobsen JV 《The Plant journal : for cell and molecular biology》2003,33(4):707-717
4.
It is well known that abscisic acid (ABA) antagonizes gibberellin (GA)-promoted seed germination. Recent circumstantial evidence
suggests that salicylic acid (SA) also inhibits seed germination in maize and Arabidopsis. Our study shows that SA blocks
barley seed germination in a dosage dependent manner. As an initial effort to addressing the mechanism controlling the crosstalk
of SA, GA and ABA signaling in barley, we studied the regulation of α-amylases by SA and a WRKY gene whose expression is modulated by these hormones. Assays of α-amylase activity reveal that GA-induced α-amylase production
in aleurone cells is inhibited by bioactive SA, but not its analogs, 3-hydroxybenzoic acid and 4-hydroxybenzoic acid. This
inhibitory effect is unlikely due to repressing α-amylase secretion or inhibiting α-amylase enzyme activities. Northern blot
analyses indicate that SA suppresses GA-induced expression of a barley low pI α-amylase gene (Amy32b). Because our previous data indicate that ABA-inducible and GA-suppressible WRKY genes inhibit the expression of α-amylase genes in rice, we studied the steady state mRNA levels of a barley WRKY gene, HvWRKY38. The expression of HvWRKY38 in barley aleurone cells is down-regulated by GA, but up-regulated by SA and ABA. However, the regulation of HvWRKY38 by SA appears to be different from that of ABA in term of the kinetics and levels of induction. Over-expression of HvWRKY38 in aleurone cells by particle bombardment blocks GA induction of the Amy32b promoter reporter construct (Amy32b-GUS). Therefore, HvWRKY38 might serve as a converging node of SA and ABA signal pathways involved in suppressing GA-induced seed
germination.
Zhen Xie and Zhong-Lin Zhang contributed equally to this work. 相似文献
5.
Bernal-Lugo I; Rodriguez M; Gavilanes-Ruiz M; Hamabata A 《Journal of experimental botany》1999,50(332):311-317
With the aim of determining the level at which ageing exerts its effect on
the expression of -amylase, GA3 regulation
of -amylase production was studied in
isolated aleurone layers from aged wheat seeds. GA3-induced
-amylase activity was lower in the tissue from aged seeds than in
controls. However, the proportion of 35S-methionine
incorporated into -amylase was higher in the aged than in control
tissue. The pattern of -amylase isoforms was resolved by
isoelectric focusing and showed that two isogroups were present with the
activity of the high-pI isogroup being higher in the control than in the
aged lot. These apparently contradictory results may be explained in terms
of differences in isozyme expression. Studies on the expression of
-amylase genes indicated a reduction in the level of high-pI mRNA
in aged tissue. Dose-response curves showed lower GA3-responsiveness of
aleurone layers from aged seeds as compared to the controls. From these
results, it is proposed that the diminished capacity of -amylase
production in aleurone from aged seeds is apparently due to a decrease in
the expression of the high-pI -amylase genes, and this reduction
is associated with a decrease in the response to GA3.Key
words: Seed ageing, wheat aleurone, gibberellic acid,
-amylase isozymes, gene expression.
相似文献
6.
7.
8.
9.
10.
11.
Gibberellins control Arabidopsis hypocotyl growth via regulation of cellular elongation 总被引:8,自引:0,他引:8
The gibberellins (GAs) are endogenous regulators of plant growth.
Experiments are described here that test the hypothesis that GA regulates
hypocotyl growth by altering the extent of hypocotyl cell elongation. These
experiments use GA-deficient and altered GA-response mutants of
Arabidopsis thaliana (L.) Heyhn. It is shown that GA
regulates elongation, in both light- and dark-grown hypocotyls, by
influencing the rate and final extent of cellular elongation. However,
light- and dark-grown hypocotyls exhibit markedly different GA
dose-response relationships. The length of dark-grown hypocotyls is
relatively unaffected by exogenous GA, whilst light-grown hypocotyl length
is significantly increased by exogenous GA. Further analysis suggests that
GA control of hypocotyl length is close to saturation in dark-grown
hypocotyls, but not in light grown hypocotyls. The results show that a
large range of possible hypocotyl lengths is achieved via dose-dependent
GA-regulated alterations in the degree of elongation of individual
hypocotyl cells.Key words: Arabidopsis, cell
elongation, gibberellin (GA), GA mutants, hypocotyl.
相似文献
12.
13.
14.
15.
The expression of -amylase genes in rice (Oryza sativa) and its regulation by phytohormones gibberellic acid (GA) and abscisic acid (ABA) were examined. Upon germination -amylase is synthesizedde novo in aleurone cells and (GA) is not required. Exogenous addition of GA does not enhance the -amylase activity, while ABA inhibits the -amylase activity, mRNA accumulation, and the germination of rice seeds. GA can reverse ABA inhibition of -amylase expression, but not ABA inhibition of seed germination. Such regulation represents a new interaction of ABA and GA. 相似文献
16.
17.
A functional assay for gibberellin (GA) receptors is described based on the induction of -amylase gene expression in isolated aleurone protoplasts of Avena fatua L. by GA4 immobilised to Sepharose beads. A 17-thiol derivative of GA4, shown to be biologically active with aleurone protoplasts, has been coupled to epoxy-activated Sepharose 6B. This GA4-17-Sepharose induces high levels of -amylase when incubated with isolated aleurone protoplasts, while cells of the intact aleurone layer do not respond appreciably to the immobilised GA4. In order to eliminate the possibility that GA4 may be released from the Sepharose when incubated with protoplasts, aleurone layers and isolated aleurone protoplasts have been co-incubated, and their responses to GA4, GA4-17-Sepharose and control Sepharose estimated by determining the relative amounts of -amylase mRNA induced in each tissue. Evidence from these experiments is consistent with the view that GA417-Sepharose induces -amylase gene expression in aleurone protoplasts by interacting with the protoplast surface. This indicates that GA receptors may be located at, or near, the external face of the aleurone plasma membrane.Abbreviation GA(n)
gibberellin A(n)
We thank Professor Jake MacMillan and Drs. Peter M. Chandler (CSIRO, Division of Plant Industry, Canberra, Australia), Peter Hedden and Johnathan Weir (Unilever, Port Sunlight, UK) for helpful discussions and suggestions. Computer graphics were performed by the University of Bristol Molecular Recognition Centre. 相似文献
18.