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Full Length Research Paper
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Effects of
gibberellin mutations on shoot bud regeneration of
Arabidopsis
Xiuhai Zhang*, Zhongyi Wu, Conglin
Huang*
Beijing Agro-Biotechnology Research Centre，Beijing
100097, China.
*Corresponding author. E-mail:
zhangxiuhai@baafs.net.cn,
conglinh@126.com.
Abbreviations:
IP, isopentenyladenin; IAA, 3-indoleacetic;
PAC, paclobutrazol;
2,4-D, 2,4-dichlorophenoxyacetic acid; NPA,
N-(1-naphthyl)
phthalamic acid;
CIM,
callus induction medium;
SIM,
shoot induction medium.
Accepted 16 May, 2008 |
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Abstract |
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Tissue culture provides
a useful system to investigate how plant hormones
are
involved in this process.
Auxin and cytokinin are widely used in plant regeneration.
Gibberellin is also an important plant hormone in regulating
plant growth and development. It is interesting to know the
effects of gibberellin and its signalling pathway on plant
regeneration.
In
this
report Arabidopsis thaliana landsberg
(wild type),
ga1-3 (gibberellin biosynthesis deficiency
mutant), gai (gibberellin insensitive mutant),
penta mutant (lacking
GA1,
GAI, RGA, RGL1, RGL2)
and
tetra mutant (lacking GAI, RGA, RGL1, RGL2)
were used
as materials to
investigate
how plant regeneration progress was affected in these
mutants under different conditions.
The
results
showed that more shoot buds were regenerated in
ga1-3 and
gai
than in wild type, penta and tetra mutant
in the normal shoot induction medium. The frequency of shoot bud regeneration in different
mutants also
varied
remarkably
when auxin : cytokinin ratio
in the medium
changed.
Only penta mutant had shoot bud regeneration without
auxin in the medium. When
the ratio
increased
wild
type,
ga1-3 and gai
had higher performance in shoot bud regeneration than
penta
mutant.
When
cytokinin level increased from 0.1 to 0.5
mg
l-1,
shoot bud regeneration frequency of ga1-3, wild
type and tetra increased remarkably except for
that of penta and gai. Only the shoot bud
regeneration frequency of gai did not change
significantly when cytokinin level increased from 0.5 to 5
mg
l-1.
These gibberellin-related mutants also responded differently
to NPA (an auxin polar transport inhibitor) in plant
regeneration. Our results indicate gibberellin and its
related pathway are also involved in plant organogenesis:
gibberellin inhibitor and auxin polar transport inhibitor
can promote plant organogenesis. This might provide a new
way for the regeneration of recalcitrant species.
Key words:
Shoot bud regeneration, Arabidopsis thaliana,
gibberellin, DELLA protein mutant.
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