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Molecular Identification of Pathogens in Nursery Crops

Molecular Identification of Pathogens in Nursery Crops. Ainong Shi. Tennessee State University. Lilac Leaf Blight. What pathogen causes this disease? How to analyze and identify it by molecular approaches?. Powdery Mildew Diseases. Dogwood. Lilac. Crape myrtle.

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Molecular Identification of Pathogens in Nursery Crops

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  1. Molecular Identification of Pathogens in Nursery Crops Ainong Shi Tennessee State University

  2. Lilac Leaf Blight What pathogencauses this disease? How to analyze and identify it by molecular approaches?

  3. Powdery Mildew Diseases Dogwood Lilac Crape myrtle • Are they caused by same pathogen? • How to analyze and identify them by molecular approaches?

  4. How to identify a pathogen by molecular approach? Lilac leaf blight for example 1

  5. Molecular Identification of Pathogen ITS universal primer analysis Specific primer analysis

  6. ITS (Internal Transcribed Spacer) (primer) ITS1 18S rDNA 5.8S rDNA 28S rDNA ITS1 ITS2 ITS4 (primer) • ITS region of rDNA has been widely used in identifying pathogens for fungal diseases in plants. • Thousands of sequences of ITS regions from fungi have been published in GenBank. • Universal primer pairs can amplify ITS region for all fungi.

  7. ITS Universal Primer Analysis A four-step procedure DNA Extraction PCR Amplification PCR Product Sequencing Similarity Analysis

  8. DNA Extraction Genomic DNA was extracted by use of the DNeasy Plant Mini Kit from Alternaria medium (mycelia and conidia) or directly from the lilac leaves of Alternaria leaf blight.

  9. PCR Amplification ITS1/ITS4 ITS universal primers: ITS1: tccgtaggtgaacctgcgg * IST4: tcctccgcttattgatatgc The primer pair ITS1/ITS4 produces a 570 bp fragment. 570 bp * White, T. J., T. Bruns, S. Lee, and J. W. Taylor. 1990. Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. Pp. 315-322 In: PCR Protocols: A Guide to Methods and Applications.

  10. PCR Product Sequence TCCGTAGGTGAACCTGCGGAGGGATCATTACACAAATATGAAGGCGGGCTGGAACCTCTCGGGGTTACAGCCTTGCTGAATTATTCACCCTTGTCTTTTGCGTACTTCTTGTTTCCTTGGTGGGTTCGCCCACCACTAGGACAAACATAAACCTTTTGTAATTGCAATCAGCGTCAGTAACAAATTAATAATTACAACTTTCAACAACGGATCTCTTGGTTCTGGCATCGATGAAGAACGCAGCGAAATGCGATAAGTAGTGTGAATTGCAGAATTCAGTGAATCATCGAATCTTTGAACGCACATTGCGCCCTTTGGTATTCCAAAGGGCATGCCTGTTCGAGCGTCATTTGTACCCTCAAGCTTTGCTTGGTGTTGGGCGTCTTGTCTCTAGCTTTGCTGGAGACTCGCCTTAAAGTAATTGGCAGCCGGCCTACTGGTTTCGGAGCGCAGCACAAGTCGCACTCTCTATCAGCAAAGGTCTAGCATCCATTAAGCCTTTTTTTCAACTTTTGACCTCGGATCAGGTAGGGATACCCGCTGAACTTAAGCATATCAATAAGCGGAGGA The sequence above amplified from the primer pair ITS1/ITS4. Primer Sequence (5’  3’) reversal sequence ITS1 TCCGTAGGTGAACCTGCGG IST4 tcctccgcttattgatatgc GCATATCAATAAGCGGAGGA

  11. Similarity Analysis BLAST Search Query: 1 tccgtaggtgaacctgcggagggatcattacacaaatatgaaggcgggctggaacctctc 60 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||| Sbjct: 25 tccgtaggtgaacctgcggagggatcattacacaaatatgaaggcgggctggaacctctc 84 Query: 61 ggggttacagccttgctgaattattcacccttgtcttttgcgtacttcttgtttccttgg 120 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||| Sbjct: 85 ggggttacagccttgctgaattattcacccttgtcttttgcgtacttcttgtttccttgg 144 …………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………………………………… Query: 541 ctgaacttaagcatatcaataagcggagga 570 |||||||||||||||||||||||||||||| Sbjct: 565 ctgaacttaagcatatcaataagcggagga 594 Query – from our data Sbject – Alternaria in GenBank 570/570 (100%) identities Analysis indicates the sequence from our data belongs to ITS region of Alternaria.

  12. Specific Primer Analysis • Develop specific primers for Alternaria genus. • Develop specific primers for A. alternata.

  13. Primer design for ITS region of Alternaria TCCGTAGGTGAACCTGCGGAGGGATCATTACACAAATATGAAGGCGGGCTGGAACCTCTCGGGGTTACAGCCTTGCTGAATTATTCACCCTTGTCTTTTGCGTACTTCTTGTTTCCTTGGTGGGTTCGCCCACCACTAGGACAAACATAAACCTTTTGTAATTGCAATCAGCGTCAGTAACAAATTAATAATTACAACTTTCAACAACGGATCTCTTGGTTCTGGCATCGATGAAGAACGCAGCGAAATGCGATAAGTAGTGTGAATTGCAGAATTCAGTGAATCATCGAATCTTTGAACGCACATTGCGCCCTTTGGTATTCCAAAGGGCATGCCTGTTCGAGCGTCATTTGTACCCTCAAGCTTTGCTTGGTGTTGGGCGTCTTGTCTCTAGCTTTGCTGGAGACTCGCCTTAAAGTAATTGGCAGCCGGCCTACTGGTTTCGGAGCGCAGCACAAGTCGCACTCTCTATCAGCAAAGGTCTAGCATCCATTAAGCCTTTTTTTCAACTTTTGACCTCGGATCAGGTAGGGATACCCGCTGAACTTAAGCATATCAATAAGCGGAGGA Primer Sequence (5’  3’) Reversal sequence Al-f1 cccaccactaggacaaaca Al-r1 gcttaatggatgctagacct aggtctagcatccattaagc The sequence size from Al-f1 to Al-r1 is 370 bp.

  14. Specific primer for Alternaria genus of ITS region • The size of band is 370 bp. • The band showed in all tested Alternaria samples. • Sequence data from the PCR amplified from the specific primer pair Al-f1/Al-r1 is identical to that in ITS region of Alternaria. 370 bp The results indicated one kind of Alternaria was the pathogen.

  15. Specific primers for Alternaria alternata (1)

  16. Specific primers for Alternaria alternata (2) 1 2 3 4 M 1500 bp 1000 bp 600 bp 300 bp 100 bp

  17. Conclusion for example 1 Alternaria alternata is one pathogen in lilac leaf blight disease. Specific primer pairs: Alternaria Al-f1/Al-r1 aa-gp-f1/aa-gp-r1 aa-hsp-f1/aa-hsp-r1 aa-hsp-f1/aa-hsp-r2 aa-his-f1/aa-his-r1 A. alternata

  18. Example two Powdery Mildew Diseases Dogwood Lilac Crape myrtle • Are they caused by same pathogen? • How to analyze and identify them by molecular approaches?

  19. Molecular Identification Approaches ITS universal primer analysis Sequence analysis Specific primer analysis

  20. ITS universal primer analysis Primer pair: ITS1/ITS4 M 1 2 3 -------------------------------------------------------------- Disease Band size Lane ---------------------------------------------------- Crape myrtle powdery mildew 666bp 1 Lilac powdery mildew 645bp 2 Dogwood powdery mildew 642bp 3 -----------------------------------------------------------------------------

  21. Sequence Analysis

  22. Specific Primer Analysis I. Erysiphe pulchra of dogwood powdery mildew M 1 2 3 4 5 6 7 8 9 M Lane 1, 4, 7 are Microsphaera syringae-japonicae Lane 2, 5, 8 are Erysiphe pulchra Lane 3, 6, 9 are Uncinuliella australiana Lane M are 100 bp ladder

  23. Specific Primer Analysis II Uncinuliella australianaof powdery mildew in crape myrtle M 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 M • The bands only for U. australiana (lane 2, 6, 10, and 14) in four • DNA groups: • Lagerstroemia indica, (2) Uncinuliella australiana, • (3) Erysiphe Pulchra, and (4) Microsphaera syringae-japonicae. • Lane M are 100 bp ladder.

  24. Specific Primer Analysis III. Microsphaera syringae-japonicae of lilac powdery mildew 1 2 3 M The band showed only for Microsphaera syringae-japonicae (lane 2) in three materials: 1. Erysiphe pulchra, 2. Microsphaera syringae-japonicae , and 3. Uncinuliella australiana. Lane M are 100 bp ladder

  25. Summary for example 2 Eight molecular markers (specific primer pairs) Primer pairs: D=ua-f1/ua-r3 E=ua-f1/ua-r4 F=ua-f3/ua-r3 G=ua-f3/ua-r4 A=EP-f6/EP-r3 B=EP-f6/EP-r4 C=EP-f6/EP-r5 H=msj-f2/msj-r1

  26. Other diseases

  27. Lilac Leaf Spot Pseudocercospora bairamifera is one pathogen in lilac leaf spot.

  28. Identification of Botryosphaeria dothidea pathogen of leaf blight disease in dogwood (Cornus florida)

  29. Oak Powdery Mildew

  30. Maple Powdery Mildew

  31. Molecular Detection of Pathogens DNA Extraction Specific Primer Design PCR Amplification Primer Test PCR Product Sequencing Sequence to Verify Similarity Analysis Pathogen Detection

  32. Face to plant diseases How can we solve them? This is our JOB!

  33. ACKNOWLEDGEMENTS Tennessee State University: Dr. Margaret Mmbaga, Dr. Sandra Reed, Dr. Nick Gawel, Dr. Roger Sauve, Dr. Suping Zhou, Dr. Emmanuel Nnodu, Dr. Frank Mrema, and Dr. Mario Keri.

  34. Thank you! Thank all of you!

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