GENET archive

[Index][Thread]

2-Plants: GE rice produced to withstand drought, salt and low temperatures



-----------------------
genet-news mailing list
-----------------------

                                  PART I
-------------------------------- GENET-news --------------------------------

TITLE:  Stress relief: Engineering rice plants with sugar-producing gene
        helps them tolerate drought, salt and low temperatures, Cornell
        biologists report
SOURCE: Cornell University, USA, press release
       http://www.news.cornell.edu/releases/Nov02/trehalose_stress.hrs.html
DATE:   Nov 25, 2002

------------------ archive: http://www.gene.ch/genet.html ------------------


Stress relief: Engineering rice plants with sugar-producing gene helps them 
tolerate drought, salt and low temperatures, Cornell biologists report

ITHACA, N.Y. -- A new strategy to genetically engineer rice and other crops 
to make them more tolerant of drought, salt and temperature stresses, while 
improving their yields, is being reported by molecular biologists at 
Cornell University.

In releasing their research, the biologists emphasize that the technique, 
which involves adding genes to synthesize a naturally occurring sugar 
called trehalose, should satisfy critics of genetically modified foods 
because the chemical composition of edible parts of plants, such as rice 
grains, remains unchanged.

The biologists describe the new strategy to help plants overcome three of 
the main causes of crop failure in Proceedings of the National Academy of 
Sciences (PNAS ), published the week of Nov. 25, 2002.

"We have demonstrated the feasibility of engineering rice for increased 
tolerance of major environmental stresses and for enhanced productivity," 
says Ray J. Wu, Cornell professor of molecular biology and genetics. He is 
director of a laboratory in the university's College of Agriculture and 
Life Sciences where stress-tolerant rice has been under development since 
1996 with support from the Rockefeller Foundation.

The Cornell biologists showed stress tolerance by introducing the genes for 
trehalose synthesis into Indica rice varieties, which represent 80 percent 
of rice grown worldwide and include the widely eaten basmati rice. But the 
same strategy, they note, should also work in Japonica rice varieties, as 
well as in a range of other crops, including corn, wheat, millet, soybeans 
and sugar cane.

The researchers plan to report on their claims of increased food 
productivity from the resulting transgenic rice plants in a subsequent 
article. They say the trehalose gene technology will be placed in the 
public domain -- instead of being sold exclusively to commercial seed 
companies -- so that improved crop varieties can be cultivated in resource-
poor parts of the world where the need is greatest.

Co-authors of the PNAS report, "Trehalose accumulation in rice plants 
confers high tolerance levels to different abiotic stresses," include 
Cornell biologists Ajay K. Garg, research associate and lead author of the 
article; Thomas G. Owen, associate professor of plant biology; Anil P. 
Ranwala, a horticulture research associate; and Leon V. Kochian, research 
leader at the U.S. Department of Agriculture-Agricultural Research Service 
Plant, Soil and Nutrition Laboratory, located on the Cornell campus. Other 
authors are South Koreans Ju-Kon Kim, a biologist at Myongji University, 
and Yang D. Choi of Seoul National University's School of Agricultural 
Technology.

Garg, a plant molecular biologist, explains why trehalose (generally 
pronounced TREE-hal-lows) was chosen in the first place: "Trehalose is a 
simple sugar that is produced naturally in a wide variety of organisms -- 
from bacteria and yeasts to fungi, including mushrooms, and in many 
invertebrates, particularly insects. But there is normally not much 
trehalose in plants, with the exception of the so-called resurrection 
plants that can survive prolonged droughts in the desert. Drought-stressed 
resurrection plants look like they are dead and gone forever; then they pop 
back to life when moisture is available," Garg says. "That's the power of 
trehalose in combating stress, and it gave us an idea to help important 
crop plants survive stress."

In their experiment, the Cornell biologists used two different E. coli 
genes that are fused together and are responsible for trehalose synthesis 
in bacteria. (Previous attempts in other laboratories had used only one 
type of trehalose gene and had been less successful because the resulting 
transgenic plants showed so-called pleiotrophic effects, including stunted 
growth, and had little tolerance for stresses.)

The Cornell biologists also learned how to add custom-designed "promoter" 
sequences to the fused genes, to allow precise "when-and-where" control 
over gene expression. Depending on the need, the trehalose genes can be 
turned on in the transgenic plants when stresses occur -- the onset of 
colder temperatures, for example. Or the gene sequence can be regulated to 
make trehalose in particular parts of the plant -- such as the leaf but not 
the edible grains.

So far the transgenic rice plants with the trehalose-enhancement gene 
sequences have been tested through five generations -- from seed-producing 
plants to seedlings and more seed-producing plants, again and again -- and 
the desirable, stress-tolerance characteristics have held true. Compared 
with non-engineered rice plants that lack the trehalose-enhancement gene 
sequences, the transgenic rice plants are much more robust under a variety 
and combination of environmental stresses.

Even when the transgenic plants are not under stress, their processes of 
photosynthesis (converting light to energy) are more efficient, the Cornell 
scientists report, accounting, in part, for the increased productivity. 
Better utilization of soil micronutrients, such as zinc and iron, also has 
been noted in the transgenic plants.

All the benefits -- and any potential liabilities -- of trehalose have yet 
to be fully explored, Garg notes. At the cellular level in plants, 
trehalose helps maintain individual cell structure and function during 
severe environmental stresses that would kill most plants. Then the sugar 
appears to help plant cells regain function and efficiency when stress is 
gone. But, Garg adds, "We still have a lot to learn about trehalose in 
important crop plants."

Likewise, several years of research-and-development work, safety testing 
and certification are ahead before large-scale production and distribution 
of transgenic rice seeds to farmers can begin. The Cornell scientists are 
seeking patent protection of the trehalose-enhancement technologies, not to 
control the market and profit from the work, but to ensure that the 
technologies can be offered in the public domain, Wu says.

"World population continues to increase at an explosive rate, our arable 
land is deteriorating, fresh water is becoming scarce and increasing 
environmental stresses pose ever more serious threats to global 
agricultural production and food security," notes Wu. "Anything we can do 
to help crop plants cope with environmental stresses will also raise the 
quality and quantity of food for those who need it most."

-30-

Contact:
Roger Segelken
Office: +1-607-255-9736
E-Mail: hrs2@cornell.edu


                                  PART II
-------------------------------- GENET-news --------------------------------

TITLE:  Transgenic rice for human benefit: a religious perspective
SOURCE: Science and Religion Information Service, USA
        http://www.eurekalert.org/pub_releases/2002-11/sari-trf112202.php
DATE:   Nov 25, 2002

------------------ archive: http://www.gene.ch/genet.html ------------------


Transgenic rice for human benefit: a religious perspective

A paper to be published in Proceedings of the National Academy of Sciences 
by A. K. Garg and R. J. Wu, "Trehalose accumulation in rice plants confers 
high tolerance levels to different abiotic stresses," shows the promise of 
biotechnology in the service of humanity, according to a religion scholar.

Statement by Ronald Cole-Turner, Ph.D., Professor of Theology and Ethics, 
Pittsburgh Theological Seminary. 412 441 3304 x2170. coleturn@pts.edu

"The work of Ajay Garg, Ray Wu, and their colleagues is highly promising 
and points forward to long-awaited benefits of the biotechnology 
revolution. Their decision to patent their work but then to release it to 
the public domain deserves high praise. This is a bold, life-affirming 
decision. The benefits of their breakthrough are likely to touch the 
world's neediest people, those whose very existence is threatened daily by 
drought or poor growing conditions. Critics of agricultural biotechnology 
have often said that the results are impractical, dangerous, or only 
beneficial to seed companies. From now on, the critics will have to think 
again. If this work is as promising as it appears, then we will need to 
worry even more about population growth. We need to have the good sense--as 
well as strong encouragement from the world's religious communities--to 
limit population while we have the chance."

Contact:
Brent Waters 
srns@science-spirit.org
+1-412-585-0842
Science and Religion Information Service



--


|*********************************************|
|                   GENET                     |
| European NGO Network on Genetic Engineering |
|                                             |
|             Hartmut MEYER (Mr)              |
|               Kleine Wiese 6                |
|           D - 38116 Braunschweig            |
|                 Germany                     |
|                                             |
| phone:  +49-531-5168746                     |
| fax:    +49-531-5168747                     |                      
| mobile: +49-162-1054755                     |
| email:  genetnl@xs4all.be                   |
|*********************************************|