Sod In Oregon as Researchers Complete Genetic Blueprint

On June 4, 2004, the Oregon Department of Agriculture (ODA) issued an emergency 90-day quarantine of all nurseries and compost production facilities in Columbia County after sudden oak death (SOD) was discovered on four rhododendrons at a single nursery in the county. Infected plants and potting media were found both inside the nursery and on the outside perimeter of the nursery.

The Columbia County growers were surveyed after trace-back information from Maryland implicated an Oregon nursery as the source of a positive find of P. ramorum, the fungus that causes SOD, in that state. According to the Oregon Association of Nurseries, Columbia County accounts for $16 million of the state’s annual $725 million in nursery sales.

The ODA collected more than 4,000 samples from the identified nursery, with four samples testing positive. More than 700 samples were collected from a surrounding area to determine if the pathogen had spread outside of the nursery, with three samples from a nearby landscape planting testing positive.

According to the ODA, the quarantine requires all nurseries in the county to have all plants susceptible to sudden oak death tested and found free of the pathogen before they are allowed for sale of in-state and out-of-state shipments. The quarantine also prohibits sale or shipment of potting media and compost produced in the county that contains material from susceptible plants unless the production facility is inspected and found free of P. ramorum and the material did not originate from areas already generally infested with SOD. Commercially produced compost containing susceptible plant material cannot be sold to nurseries unless it is sterilized by a method approved by the ODA.

ODA will destroy all infested plant material in and around the Columbia County nursery. It will require the notification of all imported nursery stock into Oregon and will survey all Oregon nurseries for any signs of SOD. “ODA officials believe the emergency quarantine will isolate the disease and keep it from becoming established in other parts of Oregon. Oregon’s nursery industry continues to provide excellent cooperation in dealing with SOD-related issues.”

Meanwhile, six days after the Oregon quarantine, researchers announced that they have completed the genetic blueprint of the blight-causing culprit responsible for SOD, according to Check BioTech. Three federal agencies have funded $4 million, producing the genetic sequence of both SOD and a close cousin responsible for destroying soybeans.

The researchers say they need to sift through the 15,000 genes of each pest in search of one gene or a combination of a few genes that make the one-cell microbes so deadly to plants. The problem is that the fungus-like pests contain about 15,000 genes each. The researchers hope they can find the bad genes by comparing the two genomes and investigating the similarities and differences between them.

“If we can figure that out and crack the code, we can develop tools to detect, prevent or cure the disease,” said Daniel Rokhsar of the Joint Genome Institute where the two genomes were produced, in Check BioTech.