DNA指纹技术--rRNA.pdfVIP

Development and Applications of Oligonucleotide Fingerprinting of rRNA Genes (OFRG) James Borneman University of California, Riverside Outline 1. Identifying microorganisms involved in suppressing the sugarbeet cyst nematode. 2. OFRG. 3. PRISE. Identifying Microorganisms that Suppress the Sugarbeet Cyst Nematode Collaborators: Ole Becker Rabiu Olatinwo Bei Yin John Darsow Lea Valinsky Funding: USDA NRI and UC IPM Sugarbeet Cyst Nematode (Heterodera schachtii) Sugarbeet cyst nematodes parasitize a wide range of crop plants such as sugarbeet, broccoli, cabbage, spinach, canola, and others (Whitehead, 1998). modified from Merny, 1972 Study Site In 1975, field 9E at UC Riverside was infested with two truckloads of soil containing high levels of the sugarbeet cyst nematode. Purpose was to create a field site to test chemical nematicides. Study Site Field 9E at Agricultural Research Station on UC Riverside campus. 1976/1977, Ivan Thomason Study Site After several years of growing host crops, the population densities of the nematode rapidly declined. The resulting soil could be classified as “suppressive,” as it keeps nematode populations low. 9E Suppressiveness is Biological Soil fumigation reduces suppressiveness. Exposure to 55C for 30 minutes reduces suppressiveness. Westphal and Becker 1999, 2001 Three Step Approach For Identifying Microbes Involved in Suppressiveness 1. Identify microorganisms that correlate with the suppressiveness using rRNA gene analysis. 2. Validate population trends using qPCR. 3. Reintroduce organisms (~Koch’s Postulates). Various Levels of Nematode Suppressiveness Were Created by So