Norwich, United Kingdom
April 26, 2004
Source: John
Innes Centre via
Innovations Report
Scientists at the
John Innes Centre
(JIC) and Institute of Food
Research (IFR), Norwich, have today reported the discovery
and use of a gene that may help protect plants and humans
against disease. The gene (HQT) was identified in tomato and is
responsible for producing an antioxidant called chlorogenic acid
(CGA).
By increasing the activity of HQT, the scientists raised the
levels of CGA in the tomato fruits and this helped protect them
against attack from bacterial disease. CGA could also protect
humans eating the tomatoes against degenerative, age-related
diseases. This report is published online on 25 April in Nature
Biotechnology and will be available in the June 2004 hard copy
journal.
“Our tomatoes are doubly special” said Dr Cathie Martin (project
leader at JIC). “They not only protect themselves against
disease, but may benefit humans that eat them by protecting
against age-related diseases. For us the excitement is that this
adds to our understanding of how plants naturally protect
themselves against stress and diseases, but in the long term it
may be that this discovery leads to fruits that are better for
us”.
The research team were interested in CGA because it is known to
be an important antioxidant in both plants and animals. The
biochemical pathway that plants use to make CGA was unknown, but
a bit of biological detective work led the team to the likely
pathway. When experiments confirmed their prediction, they were
able to isolate one of the key genes (called HQT) for making
CGA. When they suppressed the activity of the HQT gene (using
gene silencing) they found that CGA levels in developing tomato
fruits fell. The reverse happened when they increased the
activity of HQT.
Antioxidants protect against the effects of stress and disease.
To test whether higher levels of CGA give added protection the
scientists infected the high CGA tomatoes with bacteria that
cause tomato blight (Pseudomonas syringae). In the high CGA
plants the effect and spread of the disease was significantly
less than in the unmodified plants. Similarly, when the plants
were tested for resistance to oxidative stress the high CGA
plants were more resistant to stress damage than the unmodified
plants.
“This research has highlighted for me the incredible ingenuity
of plants in coping with their environment”, said Dr Tony
Michael (Project Leader at IFR). “Plants possess a whole
repertoire of genes involved in producing protective compounds.
CGA is the main polyphenol in this category in tomatoes. Now we
have identified the gene for the enzyme that produces it, we can
look for genes that produce similar compounds in other plants,
with benefits for agriculture and for human nutrition”.
The Intellectual Property Rights associated with this discovery
are assigned to Plant
Bioscience Ltd.
BACKGROUND
1) The John Innes Centre
(JIC), Norwich, UK is an independent, world-leading research
centre in plant and microbial sciences. The JIC has over 850
staff and students. JIC carries out high quality fundamental,
strategic and applied research to understand how plants and
microbes work at the molecular, cellular and genetic levels. The
JIC also trains scientists and students, collaborates with many
other research laboratories and communicates its science to
end-users and the general public. The JIC is grant-aided by the
Biotechnology and Biological Sciences Research Council. (www.jic.bbsrc.ac.uk)
2) The mission of the Institute of Food Research (www.ifr.ac.uk)
is to carry out independent basic, and strategic research on
food safety, quality, nutrition and health. It is a company
limited by guarantee, with charitable status, grant aided by the
Biotechnology and Biological Sciences Research Council (BBSRC).
3) Antioxidants are important compounds that help protect plants
and animals against the effects that stress (from disease or the
environment) has on their biology. A wide range of chemicals has
antioxidant properties. Some of the most important are phenol
compounds, such as chlorogenic acid, which accumulates to high
levels in some plants. In plants where CGA production is reduced
the cells in the mature leaves die more quickly than when CGA is
present. In animals CGA has a high bioavailability - meaning it
is readily absorbed and used by the body.
4) In tomatoes CGA is produced from caffeoyl CoA and quinic acid
by the enzyme hydroxycinnamoyl-CoA:quinate (HQT).
5) The HQT gene encodes the enzyme hydroxycinnamoyl-CoA:quinate.
The researchers produced genetically modified tomato lines using
a CaMV35S-promotor HQT fusion. In some lines the HQT gene was
silenced and in others the gene was over-expressed, resulting in
lower and higher levels of CGA respectively, compared to
unmodified plants.
6) The Intellectual Property Rights (IPR) associated with this
discovery are assigned to Plant Bioscience Limited (PBL). PBL is
a for-profit technology transfer and intellectual property
management company specializing in plant and microbial science
and is the intellectual property management company of the John
Innes Centre and the Sainsbury Laboratory. All enquiries
regarding the commercial exploitation of this IPR should be
addressed to PBL (www.pbltechnology.com)
who may be contacted on 01603 456500. |