Biotech Bouquet in the Works

By Jan Suszkiw
July 14, 1999

Sturdier breeds of lily, gladiolus and other cut-flowers may come from the greenhouse of Kathryn Kamo and her colleagues in a Beltsville, Md., laboratory operated by the Agricultural Research Service, the U.S. Department of Agriculture’s chief research agency.

Using biotechnology, the scientists are seeking to do what conventional breeding has not achieved: produce commercial cultivars with resistance to viruses that menace the nation’s $15 billion floriculture industry. One is the cucumber mosaic virus (CMV), a disease-causing pathogen that aphids spread to flower crops while probing for sap.

Spraying insecticide is one recourse. But the practice can be costly and harmful to beneficial bugs. As an alternative, Kamo’s team genetically engineered 30 strains of gladiolus with built-in defenses. About 250 of the plants are growing in a greenhouse at the U.S. National Arboretum’s Floral and Nursery Crops Research Lab in Beltsville. Operated by ARS, the arboretum itself is located in Washington, D.C.

The gladioli, now in full bloom in Beltsville, are resplendent in yellow and pink flowers. But soon, they’ll be artificially infected with CMV so scientists can check for signs of resistance or susceptibility. Virus-induced streaking in petals, brown spotting in leaves, and other unsightly symptoms can diminish a cut-flower’s aesthetic value, according to Kamo, a plant physiologist.

She is particularly anxious to test the gladioli’s durability, since they’re the first ornamental bulb crop to be engineered with a “gene gun.” The device has enabled scientists to fire bits of genetic material, called viral DNA, into cells grown from the bulbs of the gladiolus cultivars “Peter Pears” and “Jenny Lee.” From the cells, scientists grew whole plants.

This summer’s greenhouse studies will help show whether two viral coat proteins and an enzyme in the plants will foil CMV’s ability to replicate and cause disease. The trick for scientists is perfecting an inoculation technique that leaves little doubt of disease resistance. From there, it would be up to commercial florists to develop the gladiolis into new varieties.

Scientific contact: Kathryn Kamo, ARS Floral and Nursery Crops Research Lab, Beltsville, Md., (301) 504 5350, fax (301) 504-5096, kkamo@asrr.arsusda.gov.