Friday, April 25, 2003

FLOWERING TIME FINDINGS COULD EXTEND CROP OPTIONS

Long day and short day flowering are controlled by the same genes but with altered regulation. Hence, modified crops could be grown in new areas and different times of the year.

Ko Shimamoto and his colleagues at the Nara Institute of Science and Technology in Takayama, Japan raised this possibility in their work on photoperiodic control. Noting the many potential applications for agriculture, the team said that "day length requirement for any plant can be now manipulated so that we may be able to expand latitude of the areas where certain crops can be grown." One obvious application is the change of the photoperiodic requirements of crops so that they can be grown at different times of the year." Rather than there being a basic on/off switch for long days versus short days, Shimamoto believes it should be possible to fine-tune the flowering time.

The paper, "Adaptation of Photoperiodic Control Pathways Produces Short-day Flowering in Rice" by Ryosuke Hayama, Shuji Yokoi, Shojiro Tamaki, Masahiro Yano and Ko Shimamoto appears in Nature 422, 719-722.

Email the lead author at simamoto@bs.aist-nara.ac.jp.

MANNITOL GIVES GM WHEAT DROUGHT/SALT RESISTANCE

Genetically engineering wheat to express the sugar alcohol mannitol may make it more resistant to drought and salt while improving yields.

Arron C. Guenzi and colleagues at Oklahoma State University expressed the mannitol-1-phosphate dehydrogenase (mtlD) gene of Escherichia coli in wheat. Tissues or plants containing the novel gene were able to withstand water and drought stress far better than wild-type plants.

Guenzi and colleagues point out that the technique involves adding genes to synthesize the naturally occurring product. The gene occurs naturally in many food plants and is routinely used as an additive in many processed foods.

The paper, "Tolerance of Mannitol-Accumulating Transgenic Wheat to Water Stress and Salinity" by Tilahun Abebe, Arron C. Guenzi, Bjorn Martin, and John C. Cushman appears in the april 11, 2003 issue of Plant Physiology (131, 1748-1755).

Contact Arron C. Guenz at acg@okstate.edu

PROTEIN DISCOVERED FOR DISEASE PROTECTION

Scientists from the John Innes Centre, University of Edinburgh, University of Toronto and the Noble Foundation have discovered a protein central to a plant`s ability to develop long lasting immunity effective against a wide range of different diseases. Their work is expected to lead to new genetic strategies for disease protection in crops that will reduce pesticide use but maintain high yields.

According to an article in the Winter 2003 issue of Advances, a publication of the John Innes Centre and Sainsbury Laboratory , the protein DIRI 1 is essential to a plant`s internal warning system against diseases. It enables cells attacked by disease to transmit a signal that alerts other parts of the plant to the presence of infection. The induction of disease resistance is an important element in plants` strategies to protect themselves from disease attack.

More on John Innes at http://www.jic.bbsrc.ac.uk

SORGHUM GENE CONTROLS PLANT CELL WALL HARDNESS

Wilfred Vermerris, assistant professor, and Siobhan Bout, research technician, of the Agronomy and Agricultural and Biological Engineering Department, Purdue University have identified the sorghum gene that controls plant cell wall hardness. Results from the study are envisioned to improve the digestibility of livestock feed, produce hardier crops and increase the yield of biofuels.

The sorghum gene, Brown midrib (Bmr), encodes caffeic acid O-methyltransferase (COMT), a lignin-producing enzyme. This gene is involved in forming lignin, a plant cell wall hardening substance. When the gene is not functioning, or mutated, the cell walls are softer.

The researchers cloned Bmr after comparing the chemical composition of the mutants` cell walls. They also identified the part of the sorghum Brown midrib gene that is different in the three mutants, bmr12, bmr18 and bmr26.

Based on the study, sorghum mutants have reduced amounts of COMT, which is responsible for the lower lignin in the mutants` leaves and stems as compared to the wild-type crops. Mutant plants with these genetic changes have brown vascular tissue, rather than the normal green, and they are softer.

The plant-softening mutations have improved the digestibility of the food, and the livestock seem to like the new taste better. The cloning of this gene can also aid in the introduction of similar changes in other crops, such as rye grass and corn.

Contact Wilfred Vermerris of Purdue University at his email address:
Vermerris@purdue.edu for more details of the research.