Materials and Methods
I. Species-specific primer design
- A.Obtain
ribosomal gene region sequences of turfgrass species and their pathogens
- 1)Sequences obtained from GenBank
- a) Rhizoctonia solani (Brown Patch)
- b) Sclerotinia homeocarpa (Dollar Spot)
- c) Gauemannomyces graminis (Take-all Patch)
- d) Dreschlera poae (Melting Out)
- e) Colletotrichum graminicola (Anthracnose)
- f) Magnaporthe poae (Summer Patch)
- g) Pythium ultimum (Pythium Blight)
- h) Annual bluegrass
- i) Creeping bentgrass
- j) Zea mays
- 2)Sequencing done in the lab
- a) R. solani isolates
- b) Isolates of S. homoeocarpa
- c) Procedure used:
- i. Dellaporta extraction of DNA from a pure fungal culture
- ii. Polymerase Chain Reaction of extracted DNA using ITS-1 and ITS-4 primers in a Perkin-Elmer PCR
- machine
- iii. Gel electrophoresis of PCR product to determine if DNA amplification was successful
- iv. Cloning of PCR fragment using a modified version of TOPO TA Cloning by Invitrogen®
- v. Mini-prep of clones (Medhat Nakhla)
- vi. DNA was prepared for sequencing using the Wizard® Plus SV Minipreps DNA Purification process by
- Promega
- vii. DNA was sent for sequencing to the Biotechnology Center on the University of Wisconsin-Madison
- campus
- B. Compared sequences of R. solani and S. homoeocarpa to other sequences obtained
- 1) Used the Genetics Computer Group program to align DNA sequences
- 2) Regions conserved at the species level were used to design specific primers for both R. solani and S. homoeocarpa
- a) Criteria used to design primer
- i. Primer length = 20-27 nucleotides
- ii. High G+C content
- iii. Avoid complementarity at primer ends
- iv. Frame a sequence 200-500 base pairs long
- b) Compared primer with other sequences to test specificity
- c)Blasted primer on GenBank
- 3) Order primer
II. Test designed primer in the lab
- A. Used the general primers, ITS-1 and ITS-4, as positive controls for the primer tests (bands should be visible for PCR
- products of all samples)
- B. Ran PCR tests with ITS-1 and designed primer on the following samples
- 1) R. solani
- 2) S. homoeocarpa
- 3) Fusarium
- 4) Bipolaris
- 5) Annual Bluegrass
- 6) Kentucky Bluegrass
- 7) Creeping Bentgrass
III. Reduced time of diagnosis
- A. DNA extraction
- 1) Dellaporta extraction (1½ hrs.). In order to reach the goal of 4 hours, a faster extraction method was sought out.
- 2) Rapid DNA extraction (½ hr.). This method was designed for use on whiteflies, but was found to be successful on
- plant and fungal DNA.
- B. Polymerase chain reaction
- 1) Initially the Perkin-Elmer PCR machine (running time = 4 hrs.) was used.
- 2) The Rapid Cycler PCR machine (running time = 1 hr.) was employed to do the same work.