July, 2005
Source:
SpringerLink - Plant Sell Reports
Novel
insect resistance in Brassica napus developed by
transformation of chitinase and scorpion toxin genes
Jingxue Wang1, 2 , Zhenlang Chen2,
Jianzhong Du1, Yi Sun1 and Aihua Lian(3)
(1) |
The Agri-Biotechnology Research Centre of
Shanxi
Province, Taiyuan, 030031, P.R. China |
(2) |
The Key Laboratory of Gene Engineering of Ministry of
Education,
Sun
Yat-sen University, Guangzhou, 510275, P. R. China |
(3) |
Institute of Biotechnology, Shanxi University, Taiyuan,
030006, P.R. China |
Received:
12 October 2004 Revised:
14 March 2005 Accepted:
15 March 2005 Published
online: 19 July 2005
Communicated by I. S. Chung
ABSTRACT
Transgenic
plants with introduced pest-resistant gene offer an efficient
alternative insect control. The novel insect-resistant gene
combination, chitinase(chi) and BmkIT(Bmk),
containing an insect-specific chitinase gene and a scorpion
insect toxin gene was introduced into Brassica napus
cultivar via Agrobacterium-mediated transformation.
Fifty-seven regenerated plantlets with kanamycin-resistance were
obtained. Transgenic plants were verified by Southern blot
analysis. Enzyme-linked immunosorbent assay (ELISA) and bioassay
of artificial inoculation with diamondback moth (Plutella
maculipenis) (DBM) larvae indicated that some of the
transgenic plants were high-level expression for both chitinase
and scorpion toxin proteins and performed high resistance
against the tested pest infestation. The genetic analysis of
T1 progeny confirmed that the inheritance of
introduced genes followed the Mendelian rules.
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SciDev.Net
Chinese scientists have inserted scorpion and
moth genes into oilseed rape (canola) plants to make them
poisonous to insects feeding on them.
The researchers say that using two foreign genes
at the same time means insect pests will be less likely to
develop resistance to the genetically modified (GM) plants. The
findings were published online in Plant Cell Report on 19
July.
The researchers tested the GM plants by exposing
them to caterpillars of the diamondback moth (Plutella
maculipenis). All of the plants showed some defense against
the caterpillars, although the extent of this varied from plant
to plant.
The caterpillars, which are major crop pests in
parts of Africa, Asia and Latin America, have developed
resistance to several available pesticides. There are also
reports they are becoming resistant to 'Bt' plants, which are
genetically modified to produce a toxin that kills insects but
is harmless to birds and mammals.
The Chinese team, led by Jingxue Wang of the
Agri-Biotechnology Research Centre of Shanxi Province, inserted
two genes at once to overcome this problem.
The gene from the Asian scorpion (Buthus
martensii) produces a poison that specifically
affects insect nervous systems, leading to paralysis. The gene
from the tobacco hawkmoth (Manduca sexta) produces a
chemical that breaks down chitin, a major component of insects'
outer surface and gut lining.
Because it is unlikely that a caterpillar would
be able to resist both toxins at once, the researchers say their
approach could slow down and minimise the chance of an insect
developing resistance to the plants.
They also suggest using their approach in
combination with the Bt toxin genes already widely used.
Lead researcher Wang, told SciDev.Net the team is
trying the same combination of genes in GM cotton.
Eric
Messens, a professor of plant molecular genetics at Flanders
Interuniversity Institute for Biotechnology at Ghent University,
Belgium, warns however that some scorpion toxins previously
thought to affect only insects can also affect mammals.
He told
SciDev.Net that detailed studies must be conducted to see
whether the toxins produced by the GM plants affect human
health.
Another
concern about GM oilseed rape is that insects or the wind could
carry pollen with foreign genes into non-GM oilseed rape crops
or related species.
"Discussions about biosafety should be based on the results of
practical case studies and not on worst case scenarios," says
Gerhard Schwarz, a researcher at the Germany-based EpiGene
company.
Schwarz and colleagues published a two-year field
study of GM oilseed rape online in the European Journal of
Agronomy on 21 June.
The team found that genetic contamination of
non-GM plants with GM genes could be kept below the 0.9 per cent
level required by European food labelling rules, without
limiting the distance between the two sets of crops.
"Our
results showed that the gene flow by pollen dispersal can be
brought under control and does not lead to a biological
catastrophe," Schwarz told SciDev.Net.
GM crops
can therefore co-exist with conventional and organic farming, he
added.
Link to abstract of paper in Plant Cell Report
Reference: Plant Cell Report doi:
10.1007/s00299-005-0967-3
Link to abstract of paper in
European Journal of Agronomy
Reference:
European Journal of Agronomy doi: 10.1016/j.eja.2005.04.002 |