Research Tools for Longer Lasting Blooms

Researchers at the USDA-Agricultural Research Service's Crops Pathology and Genetics Research Unit, Davis, California in collaboration with co-investigators from the Universities of Florida and Reading (UK) have been probing the underlying causes and gene controlled mechanisms of aging. In one study conducted by University of California Davis, Cai-Zhong Jiang and Michael Reid found that spraying of low concentrations of thidiazuron (TDZ), extended the life cycle of potted plants' leaves and flowers. To understand further how TDZ works and to make it more effective to potted flowers other than roses, the team used the molecular technique called "virus-induced gene silencing" or VIGS.

The technique involves the insertion of desired genes into the virus, infection of the plant with the modified virus and comparing the infected plant with the non-infected plants. The techniqure relies on the plants'  natural defense mechanism to silence the invading virus. Proof of concept experiments conducted with petunia showed that gene silencing sequences for imparting color and ethylene production inserted into the infecting virus resulted in the development of white splotches of sectors in purple flowers and reduced production of ethylene - the compound that induces aging. "The basic idea here is that we can use the virus as a tool to quickly turn off genes, to see which ones control senescence," says Jiang.

More details can be found in the news article at http://www.ars.usda.gov/is/AR/archive/apr10/blooms0410.htm.