Genetic Diversity among Imperata cylindrica

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Genetic Diversity among Imperata cylindrica

• Josiah Raymer,
• Undergraduate Research Assistant
• Mack Thetford,
• Associate Professor
• West Florida Research and Education Center,
  Milton, FL
• Institute of Food and Agricultural Sciences
• University of Florida

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Background Information Imperata cylindrica Cogon
Grass

• Invasive weed
• No reliable methods of control
• Obligate outcrosser (can not self fertilize)
• Lack of genetic diversity (clonal populations)
• Red leaf variants are sold as an ornamental
• Limited knowledge of genetic relationship

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Imperata cylindrica Cogon Grass
Variety? Cultivar? Cultivar of a variety?
Cranberry Grass Red Baron Grass Red Baron
Cranberry Grass Imperata cylindrica
rubra Imperata cylindrica Red Baron Imperata
cylindrica rubra Red Baron
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Objectives

• Develop a reliable method of extracting
  amplifiable DNA from both red and green leaf
  selections of Imperata
• Determine if diversity exists among red leaf
  selections of Imperata

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Objective 1

• Determine a reliable DNA extraction method
• Evaluate the effectiveness of two alternative DNA
  extraction procedures compared to the standard
  CTAB procedure to obtain amplifiable DNA

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Qiagen DNeasy Extraction

• DNeasy Plant Mini Kits
• A commercially available Plant DNA extraction kit

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Amplification

• RAPD/PCR reactions
• Replication of DNA fragments of specific size
  based on the primer used in the reaction
• Gel Electrophoresis
• Separation of DNA fragments of specific size
  using an electrical current

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Amplification (Qiagen)

• DNA from green leaf samples produced well
  amplified fragments
• ? DNA from red leaf samples did not produce
  amplified fragments

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DNA Purification (red samples)

• Centricon
• YM-100 ultrafilters
• Membrane based filtration tubes

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Results of Amplification

• ? Ultrafiltered DNA isolated from red leaf
  Imperata via Qiagen DNeasy kits, produced
  amplified fragments

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Results

• DNA of green leaf Imperata extracted using the
  Qiagen DNeasy kits produced amplifiable DNA
• DNA of red leaf Imperata extracted using the
  Qiagen DNeasy kits required an extra
  ultrafiltration step before amplification
  occurred

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Objective 2

• Is There Genetic Diversity Within Selections of
  Red Leaf Cogongrass?
• Are Red Leaf Selections similar to Green Leaf
  Selections?

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Samples

• 29 Samples
• 13 green leaf (UF Collection)
• 16 red leaf (multiple industry sources)

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Amplification

• RAPD/PCR
• 5 Primers
• 5 Different fingerprints/sample
• Horizontal gel electrophoresis
• Digital Images

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Gel Images Imperata cylindrica Cogon Grass
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Gel Processing

• Gel imaging software (Gel Comprar II)
• 5 fingerprints for each sample were linked to
  form a composite data set
• Dendogram was constructed
• Principal component analysis
• Jacknife comparison

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Dendogram Imperata cylindrica Cogon Grass
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Principal Component Analysis Imperata
cylindrica Cogon Grass
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Jackknife comparisonImperata cylindrica Cogon
Grass
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Conclusions

• Red and green leaf selections of Imperata
  cylindrica were separated into two distinct
  groups.

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Conclusions

• Red leaf selections of Imperata cylindrica were
  further separated into two distinct groups.

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Significance to Industry

• Genetic diversity is present within populations
  of red and green leaf selections of cogongrass.
• Potential exists for cross pollination between
  the different selections.