trends in plant science Headlines
Seminis eliminates 2000 varieties Seminis (Oxnard, CA, USA) announced that it would eliminate 2000 varieties or 25% of its total product line as a cost-cutting measure. Seminis, a subsidiary of the Mexican conglomerate Savia and controlling nearly a fifth of the worldwide fruit and vegetable seed market, gained .8000 varieties comprising 60 species of fruits and vegetables by acquiring a dozen or so seed companies, most notably, the garden seed division of Asgrow, Petoseed and Royal Sluis. The company has 79 issued or allowed patents, and is seeking patents related to beans, bean sprouts, broccoli, cauliflower, celery, corn, cucumber, eggplant, endive, leek, lettuce, melon, muskmelon, onion, peas, pumpkin, radish, red cabbage, spinach, squash, sweet pepper, tomato, watermelon and white cabbage.
Preventing cyanide release from cyanogenic glycosides Plants that produce hydrogen cyanide gas to protect themselves against predators can do so by the enzymatic breakdown of a class of compounds known as cyanogens, such as cyanogenic glycosides. In a study by Helene Engler and colleagues (University of Texas, Austin, TX, USA), a neotropical butterfly, Heliconius sara, can avoid the harmful effects of the cyanogenic leaves of Passiflora auriculata (passion vine) by a a unique enzymatic conversion. The mechanistic details of this pathway might suggest new ways to make cyanogenic crops more useful as a food source. http://uts.cc.utexas.edu/~gilbert/research/ butterflies/
Agritope analyses phytochemicals
New generation selection genes
Fusarium control by Fusarium
Agritope, Inc. (Portland, OR, USA) is developing new plant varieties containing increased levels of naturally occurring phytochemicals. Agritope’s MetaGene™ Metabolic Genomics Technology facilitates the identification of specific genes that regulate the levels of phytochemicals such as carotenoids, lycopene, flavonoids, isoflavones, vitamins, folic acid and various elements and minerals.
Marker genes enable scientists to select a rare transformed plant cell after co-introducing the desired gene along with the marker. Beyond the laboratory, these markers have no role and thus their presence in crops and food has provoked much public concern, especially because these genes either code for antibiotic or herbicide resistance. Solutions that have been proposed include the removal of marker genes using the Cre-lox system or transposable elements, or new positive selectable systems. The manAgene encoding PMI was cloned from E. coli by researchers at Danisco Biotechnology (Copenhagen, Denmark) Plant cells transformed with this gene can uniquely convert mannose-6-phosphate to fructose-6phosphate, which is then easily metabolized. An increased transformation efficiency might occur because transformed cells are actively encouraged to grow rather than just allowed to survive. Researchers interested in obtaining the manA gene or who require more information about this Positech system can contact: Andy Beadle at [email protected]
To control Fusarium wilt disease in an environmentally friendly way, beneficial strains of Fusarium are being used to control plant pathogenic strains of Fusarium oxysporum. Deborah R. Fravel (Agriculture Research Service, Beltsville, MD, USA) and George Lazarovits (Agriculture and Agri-Food Canada, Ontario, Canada) found one strain, CS-20, which reduced wilt by 49.6%. Mixing beneficial strains of a fungus (Trichoderma virens strain G1-3) and a bacterium (Burkholderia vietnamiensis strain Bc-F) also reduced wilt incidence by 41.6%. The mechanism of biocontrol might rely on induced systemic resistance. http://www.ars.usda.gov/is/pr/2000/000714.htm
Rice genome news A new website http://www.rice-research.org provides access to the Monsanto Rice Genome Sequence data at no charge. Monsanto is collaborating with the International Rice Genome Sequencing Project (IRGSP) to complete and publish the entire genome sequence. Information on the IRGSP program can be found at http://rgp.dna.affrc.go.jp/Seqcollab.html
Fusarium considered to kill coca plants Colombia has reluctantly agreed to take steps in developing a Fusarium oxysporum mycoherbicide against the coca and heroin-poppy fields. A proposal will be made to the United Nations that would include testing for the presence of the fungus in coca. Environmentalists and other activists in both countries object to any field tests of the fungus, arguing that it is virtually a biological weapon – one that might upset Colombia’s ecology or endanger farmers, animals and food crops.
UV-B susceptibility in plants Barbara Hohn and colleagues (Friedrich Miescher Institute, Basel, Switzerland) report that excessive UV-B radiation damages DNA in plants and stunts their growth, that the plants’ susceptibility accumulates over generations and could worsen if the depletion of the earth’s protective ozone layer continues at its current pace. http://www.fmi.ch/reports/Hohnb.htm
1360 - 1385/00/$ – see front matter © 2000 Elsevier Science Ltd. All rights reserved.
Floral scent research Improving floral scent is one of the goals of the $20 billion per year horticulture industry. The aroma of a flower can contain as few as seven different oils, such as in snapdragon (Antirrhinum majus), or as many as 100 such as in orchids. In snapdragon flowers, the volatile ester methyl benzoate is the most abundant scent compound. Natalia Dudareva (Purdue University, West Lafayette, IN, USA) isolated a novel S-adenosyl-L-methionine:benzoic acid carboxyl methyltransferase (BAMT), the final enzyme in the biosynthesis of methyl benzoate, and characterized its corresponding cDNA. www.plantcell.org/cgi/content/full/12/6/949; www.hort.purdue.edu/hort/people/faculty/ dudareva.html Internet news media, edited by Gert E. de Vries.
October 2000, Vol. 5, No. 10