Canada Research Chair in Bioorganic and Agricultural Chemistry

Questions about our research?

s.pedras@usask.ca

Group Photos

Department of Chemistry

Chemical Ecology & Natural Products Chemistry: Discovering Sustainable Plant Disease Treatments

Despite extensive use of fungicides, insecticides, and herbicides, plant diseases and pests continue to cause enormous yield losses worldwide. Yet, the increasing demand for food requires substantial increases in the production of staple crops. At the same time, environmental issues stress that sustainable agricultural practices cannot rely on the continuous application of pesticides. For this reason, there is an urgency to fully understand both our agricultural and natural ecosystems. This understanding requires a concerted multidisciplinary effort, which demands a multidisciplinary approach. In particular, application of chemical ecology to understand the multiple chemical interactions among various organisms is central to the discovery of safer agricultural practices and indeed universally sustainable crop production.

In our group we are using bioorganic, biochemical and biological techniques to understand economically important diseases of crucifers, namely oilseeds such as canola, rapeseed, and mustard, vegetables such as rutabaga, broccoli, and turnip, and condiments such as radish and wasabi. In addition, a particular effort to discover wild species displaying unique defense pathways is underway. We are focusing on the interactions of these plants with significant fungal pathogens such as blackleg, black spot, root rot, stem rot, grey mould and white rust (Figure 1). Experimental work combines a wide variety of chemical and biological studies including:

  • chemical structure determination of bioactive metabolites synthesized by pathogens (e.g. phytotoxins and elicitors) and plants (e.g. phytoalexins and phytoanticipins) with development of bioassays;

  • biosynthesis and metabolism of these bioactive compounds in pathogens and plants;

  • chemical synthesis of bioactive compounds and intermediates/products of detoxification pathways;

  • isolation and characterization of detoxifying enzymes;

  • design of inhibitors: paldoxins (inhibitors of phytoalexin detoxifying enzymes) and inhibitors of phytotoxin biosynthesis.

 

Figure 1. Overview of current research work: chemistry and biochemistry of plant-fungal interactions..

 

 

Research positions available

BIOORGANIC, BIOLOGICAL and NATURAL PRODUCTS CHEMISTRY

GRADUATE STUDENT POSITIONS 

Exceptionally talented and highly committed graduate students that qualify for admission by the College of Graduate Studies and Research of the University of Saskatchewan (http://www.usask.ca/cgsr) and the Department of Chemistry, interested in initiating Ph.D. research projects in topics described above or related should send electronic application (pdf files only!) to:

DR. M. S. C. PEDRAS

UNIVERSITY OF SASKATCHEWAN

Department of Chemistry

110 SCIENCE PLACE

SASKATOON SK, S7N 5C9, CANADA

Internet: s.pedras@usask.ca

 

http://artsandscience.usask.ca/profile/MPedras 

http://www.usask.ca/chemistry/groups/pedras/

http://www.chairs-chaires.gc.ca/chairholders-titulaires/profile-eng.aspx?profileId=1429

 

POST-DOCTORAL POSITIONS

Ongoing research PROJECTS to investigate the metabolism of biologically active secondary metabolites and their receptors require postdoctoral fellows:

1- Ph. D. in Bioorganic/Biological Chemistry or related field, a strong background in fungal and plant enzyme isolation/characterization, extensive experience with HPLC analysis (diode array and radio detectors) and CapLC-MS peptide identification.

2- Ph. D. in Organic/Bioorganic Chemistry or related field, experience with synthesis of biotinylated probes and isotopically labelled metabolites and analogs, proven expertise in spectroscopic techniques necessary for chemical structure elucidation, particularly modern high field NMR spectroscopy and HPLC-MS, extensive experience with HPLC analysis (diode array and mass detectors).

Additionally, all positions require experience in developing biological assays to determine bioactivity (antifungal, antibacterial, phytotoxic, cytotoxic) of secondary metabolites. The required qualifications should be evidenced by a strong international publication record in the field.

Candidates should send electronic application and CV (pdf files only!), and provide names, e-mail addresses, and telephone numbers of three referees to Dr. M. S. C. PEDRAS, to the address shown above.

 

Research Funding Agencies

  • NSERC(Natural Sciences and Engineering Research Council)

  • CFI (Canada Foundation for Innovation)

  • CRC (Canada Research Chairs) Chair in Bioorganic and Agricultural Chemistry

  • Government of Saskatchewan

  • Saskatchewan Agriculture and Development Fund

  • Canola Council of Canada

 

Selected publications

Pedras, M. S. C.;* Minic, Z.; Abdoli, A. 2014. The phytoalexin camalexin induces fundamental changes in the proteome of Alternaria brassicicola different from those caused by brassinin.Fungal Biology, 118, 83-93.

Pedras, M. S. C.;* Minic, Z. 2014. The phytoalexins brassilexin and camalexin inhibit cyclobrassinin hydrolase, a unique enzyme from the fungal pathogen Alternaria brassicicola. Bioorganic & Medicinal Chemistry, 22, 459-467.

Pedras, M. S. C.;* Abdoli, A. 2013. Metabolism of the phytoalexins camalexins, their bioisosteres and analogues in the plant pathogenic fungus. Alternaria brassicicola. Bioorganic & Medicinal Chemistry, 21 4541?4549.

Pedras, M. S. C. 2013. Metabolism and detoxification of phytoalexins from crucifers and application to the control of fungal plant pathogens. Biotechnology of Crucifers, S. Gupta, ed., Springer, 151-171.

Pedras, M. S. C.;* Yaya, E. E. 2013v. Dissecting metabolic puzzles through isotope feeding: novel amino acid in the biosynthetic pathway of the phytoalexins rapalexin A and isocyalexin A. Organic & Biomolecular Chemistry, 11, 1149?1166.

Pedras, M. S. C.;* Abdoli, A; Chumala, P. B.; Saha, P.; Schatte, G. 2013v. Unprecedented spirocyclization of 3-methyleneindoline-2-thiones during hydrolysis of the phytoalexin cyclobrassinin. Bioorganic & Medicinal Chemistry Letters, 23, 484?487.

Pedras, M. S. C.;* Sarma-Mamillapalle, V. K. 2012v. Metabolism and metabolites of dithiocarbamates in Leptosphaeria maculans, Journal of Agricultural & Food Chemistry, 60, 7792-7798.

Pedras, M. S. C.;* Sarma-Mamillapalle, V. K. 2012v. The phytoalexins rapalexin A, brussalexin A and erucalexin: chemistry and metabolism in Leptosphaeria maculans. Bioorganic & Medicinal Chemistry, 20, 3991-3996.

Pedras, M. S. C.;* Abdoli, A; Chumala, P. B.; Saha, P.; Schatte, G. 2012. Unprecedented spirocyclization of 3-methyleneindoline-2-thiones during hydrolysis of the phytoalexin cyclobrassinin. Bioorganic & Medicinal Chemistry Letters, 10.1016/j.bmcl.2012.11.042.

Pedras, M. S. C.;* Sarma-Mamillapalle, V. K. 2012. Metabolism and metabolites of dithiocarbamates in Leptosphaeria maculans. Journal of Agricultural & Food Chemistry, 60, 7792-7798.

Pedras, M. S. C.;* Yaya, E. E. 2012. The first isocyanide of plant origin expands functional group diversity in cruciferous phytoalexins: synthesis, structure and bioactivity of isocyalexin A. Organic & Biomolecular Chemistry, 10, 3613-3616.

Pedras, M. S. C.;* Khallaf, I. 2012. Molecular interactions of the phytotoxins destruxin B and sirodesmin PL with crucifers and cereals: metabolism and elicitation of plant defenses. Phytochemistry, 77, 129-139.

Pedras, M. S. C.;* Sarma-Mamillapalle, V. K. 2012. The phytoalexins rapalexin A, brussalexin A and erucalexin: chemistry and metabolism in Leptosphaeria maculans. Bioorganic & Medicinal Chemistry, 20, 3991-3996.

Pedras, M. S. C.;* Minic, Z. 2012. Differential protein expression in response to the phytoalexin brassinin identifies molecular targets in the phytopathogenic fungus Alternaria brassicicola. Molecular Plant Pathology, 13, 483-493.

Pedras, M. S. C.;* Minic, Z.; Hossain, S. 2012. Discovery of inhibitors and substrates of brassinin hydrolase: Probing selectivity with dithiocarbamate bioisosteres. Bioorganic & Medicinal Chemistry, 20, 225-233.

Pedras, M. S. C.;* Hossain, S. 2011. Interaction of phytoanticipins with plant fungal pathogens: indole glucosinolates are not metabolized but the corresponding desulfo-derivatives and nitriles are. Phytochemistry, 72, 2308-2316.

Pedras, M. S. C.;* Yaya, E. E.; Glawischnig, E. 2011. The phytoalexins from cultivated and wild crucifers: Chemistry and biology. Natural Product Reports, 28, 1381-1405.

Pedras, M. S. C.;* Chumala, P. B. 2011. Maculansins, cryptic phytotoxins from blackleg fungi. Natural Product Communications, 6, 617-620.

Pedras, M. S. C.;* Minic, Z.; Sarma-Mamillapalle, V. K. 2011. Brassinin oxidase mediated transformation of the phytoalexin brassinin: Structure of the elusive co-product, deuterium isotope effect and stereoselectivity. Bioorganic & Medicinal Chemistry, 19, 1390-1399.

Pedras, M. S. C.;* Hossain S.; Snitynsky, R. B. 2011. Detoxification of cruciferous phytoalexins in Botrytis cinerea: spontaneous dimerization of a camalexin metabolite. Phytochemistry, 72, 199-206.

Pedras, M. S. C. 2011. Fungal attack and cruciferous defenses: tricking plant pathogens. Recent Advances in Phytochemistry, 41, 127-139.

Pedras, M. S. C.;* Minic, Z.; Devi, P. T.; Bhaskar, V.; Montaut, S. 2010. Indolyl-3-acetaldoxime dehydratase from the phytopathogenic fungus Sclerotinia sclerotiorum: Purification, characterization, and substrate specificity. Phytochemistry, 71, 1952-1962.

Pedras, M. S. C.;* Yaya, E. E.; Hossain S. 2010. Unveiling the phytoalexin biosynthetic puzzle in salt cress: Unprecedented incorporation of glucobrassicin into wasalexins A and B. Organic & Biomolecular Chemistry, 8, 5150-5158.

Pedras, M. S. C.;* Snitynsky, R. B. 2010. Impact of cruciferous phytoalexins on the detoxification of brassilexin by the blackleg fungus pathogenic to brown mustard. Natural Product Communications, 5, 883-888.

Pedras, M. S. C.;* Yaya, E. E. 2010. Phytoalexins from Brassicaceae: news from the front. Phytochemistry, 71, 1191-1197.

Pedras, M. S. C.;* Minic, Z.; Sarma-Mamillapalle, V.; Suchy, M. 2010. Discovery of inhibitors of brassinin oxidase based on the brassilexin and wasalexin scaffolds. Bioorganic & Medicinal Chemistry, 18, 2456-2463.

Pedras, M. S. C.;* Zheng, Q. A. 2010. Metabolic responses of Thellungiella halophila/salsuginea to biotic and abiotic stresses: Metabolite profiles and quantitative analyses. Phytochemistry, 71, 581-589.

Pedras, M. S. C.;* Zheng, Q. A. 2010. Development and Modification of Bioactivity - Products: The Chemistry of Arabidopsis thaliana. In Comprehensive Natural Products II Chemistry and Biology; Mander, L., Lui, H.-W., Eds.; Elsevier: Oxford, 2010; volume 3, pp. 1297-1315. (INVITED REVIEW).BC

Pedras, M. S. C.;* Zheng, Q. A.; Shatte, G.; Adio, A. M. 2009. Photochemical dimerization of wasalexins in UV-irradiated Thellungiella halophila and in vitro generates unique cruciferous phytoalexins. Phytochemistry, 70, 2010-2016.

Pedras, M. S. C.;* Minic, Z.; Sarma-Mamillapalle, V. 2009. Substrate specificity and inhibition of brassinin hydrolases, detoxifying enzymes from the plant pathogens Leptosphaeria maculans and Alternaria brassicicola. FEBS Journal, 276, 7412-7428.

Pedras, M. S. C.;* Yu, Y. 2009. Phytotoxins, elicitors and other secondary metabolites from phytopathogenic blackleg fungi: structure, phytotoxicity and biosynthesis. Natural Product Communications, 4, 1291-1304 (REVIEW).

Pedras, M. S. C.;* Okinyo-Owiti, D. P.; Thoms, K.; Adio, A. M. 2009. The biosynthetic pathway of crucifer phytoalexins and phytoanticipins: de novo incorporation of deuterated tryptophans and quasi-natural compounds. Phytochemistry, 70, 1129-1138.

120. Pedras, M. S. C.;* Zheng, Q. A. 2009. Phytoalexins. In Biology and Breeding of Crucifers, CRC Press, Ed. Gupta, S. K., pp. 249-259 (INVITED REVIEW).

Pedras, M. S. C.;* Minic, Z.; Sarma-Mamillapalle, V. 2009. Synthetic inhibitors of the fungal detoxifying enzyme brassinin oxidase based on the phytoalexin camalexin scaffold. Journal of Agricultural & Food Chemistry, 57, 2429-2435.

Pedras, M. S. C.;* Chumala, P. B.; Jin, W.; Islam, M. S.; Hauck, D. W. 2009. The phytopathogenic fungus Alternaria brassicicola: Phytotoxin production and phytoalexin elicitation. Phytochemistry, 70, 394-402.

Pedras, M. S. C.;* Yu, Y. 2009. Mapping the sirodesmin PL biosynthetic pathway: a remarkable intrinsic steric deuterium isotope effect on a BH NMR chemical shift determines β-proton exchange in tyrosine. Canadian Journal of Chemistry 87, 556-562.

Sexton, A. C.; Minic, Z.; Cozijnsen, A. C.; Pedras, M. S. C.; Howlett, B. J. 2009. Cloning, purification and characterization of brassinin glucosyltransferase, a phytoalexin-detoxifying enzyme from the plant pathogen Sclerotinia sclerotiorum. Fungal Genetics and Biology, 46, 201-209.

Pedras, M. S. C.;* Yu, Y. 2009. Salt stress induces production of melanin related metabolites in the phytopathogenic fungus Leptosphaeria maculans. Natural Products Communications, 4, 53-58.

Pedras, M. S. C.;* Yu, Y. 2008. Structure and biological activity of maculansin A, a phytotoxin from the phytopathogenic fungus Leptosphaeria maculans. Phytochemistry, 69, 2966-2971.

Pedras, M. S. C.;* Zheng, Q. A.; Strelkov, S. 2008. Metabolic changes in roots of the oilseed canola infected with the biotroph Plasmodiophora brassicae: phytoalexins and phytoanticipins. Journal of Agricultural & Food Chemistry, 56, 9949-9961.

Pedras, M. S. C.;* Yu, Y. 2008. Stress-driven discovery of metabolites from the fungal plant pathogen Leptosphaeria maculans: structure and activity of leptomaculins. Bioorganic & Medicinal Chemistry, 16, 8063-8071.

Pedras, M. S. C.;* Gadagi, R. S.; Zheng, Q. A.; Rimmer, S. R. 2008. Selective elicitation of the phytoalexin rutalexin in rutabaga and turnip roots by a biotrophic plant pathogen. Natural Product Communications, 3, 1239-1243.

Pedras, M. S. C.;* Minic, Z.; Jha, M. 2008. Brassinin oxidase, a fungal detoxifying enzyme to overcome a plant defense: purification, characterization and inhibition. FEBS Journal, 275, 3691-3705.

Pedras, M. S. C. 2008. The chemical ecology of crucifers and their fungal pathogens: boosting plant defenses and inhibiting pathogen invasion. The Chemical Record, 8, 109-115. (INVITED REVIEW)

Pedras, M. S. C.;* Adio, A. M. 2008. Phytoalexins and phytoanticipins from the wild crucifers Thellungiella halophila and Arabidopsis thaliana: rapalexin A, wasalexins and camalexin. Phytochemistry, 69, 889-893.

Pedras, M. S. C.; Okinyo, D. P. O. 2008. Remarkable incorporation of the first sulfur containing indole derivative: Another piece in the puzzle of crucifer phytoalexins. Organic & Biomolecular Chemistry, 6, 51-54.

Pedras, M. S. C.;* Zheng, Q. A.; Gadagi, R. S.; Rimmer, S. R. 2008. Phytoalexins and polar metabolites from the oilseeds canola and rapeseed: Differential metabolic responses to the biotroph Albugo candida and to abiotic stress. Phytochemistry, 69, 894-910.

Pedras, M. S. C.;* Jha, M.; Minic, Z.; Okeola, O. G. 2007. Isosteric probes provide structural requirements essential for detoxification of the phytoalexin brassinin by the fungal pathogen Leptosphaeria maculans. Bioorganic & Medicinal Chemistry, 15, 6054-6061.

Pedras, M. S. C.;* Hossain, M. 2007. Design, synthesis, and evaluation of potential inhibitors of brassinin glucosyl transferase, a phytoalexin detoxifying enzyme from Sclerotinia sclerotiorum. Bioorganic & Medicinal Chemistry, 15, 5981-5996.

Pedras, M. S. C.;* Gadagi, R. S.; Jha, M.; Sarma-Mamillapalle, V. K. 2007. Detoxification of the phytoalexin brassinin by isolates of Leptosphaeria maculans pathogenic on brown mustard involves an inducible hydrolase. Phytochemistry, 68, 1572-1578.

Pedras, M. S. C.;* Chumala, P. B.; Yu, Y. 2007. The phytopathogenic fungi Leptosphaeria maculans and L. biglobosa: chemotaxonomical characterization of isolates and metabolite production in different culture media. Canadian Journal of Microbiology, 53, 364-371.

Pedras, M. S. C.;* Zheng, Q. A.; Sarwar, M. G. 2007. Efficient synthesis of brussalexin A, a remarkable phytoalexin from Brussels sprouts. Organic & Biomolecular Chemistry, 5, 1167-1169.

Pedras, M. S. C.;* Zheng, Q. A.; Sarma-Mamillapalle, V. K. 2007. The Phytoalexins from Brassicaceae: structure, biological activity, synthesis and biosynthesis. Natural Product Communications, 2, 319-330. (INVITED REVIEW)

Pedras, M. S. C.;* Zheng, Q. A.; Gadagi, R. S. 2007. The first naturally occurring aromatic isothiocyanates, rapalexins A and B, are cruciferous phytoalexins. Chemical Communications, 368 - 370.

Pedras, M. S. C.;* Suchy, M. 2006. Metabolism of the crucifer phytoalexins wasalexins A and B in the plant pathogenic fungus Leptosphaeria maculans. Organic and Biomolecular Chemistry, 4, 3526 - 3535.

Pedras, M. S. C.;* Adio, A. M.; Suchy, M.; Okinyo, D. P. O; Zheng, Q. A.; Jha, M.; Sarwar, M. G. 2006. Detection, characterization and identification of crucifer phytoalexins using high-performance liquid chromatography diode array and electrospray ionization mass spectrometry. Journal of Chromatography A, 1133, 172-183.

Pedras, M. S. C.;* Sarwar, M. G.; Suchy, M.; Adio, A. M. 2006. The phytoalexins from cauliflower, caulilexins A, B and C: isolation, structure determination, syntheses and antifungal activity. Phytochemistry, 67, 1503-1509.

Pedras, M. S. C.;* Hossain, M. 2006. Metabolism of crucifer phytoalexins in Sclerotinia sclerotiorum: detoxification of strongly antifungal compounds involves glucosylation. Organic & Biomolecular Chemistry, 4, 2581-2590.

Pedras, M. S. C.;* Okinyo, D. P. O. 2006. En route to erucalexin: a unique rearrangement in the crucifer phytoalexin biosynthetic pathway. Chemical Communications, 1848-1850.

Pedras, M. S. C.;* Jha, M. 2006. Toward the control of Leptosphaeria maculans: design, syntheses, biological activity and metabolism of potential detoxification inhibitors of the crucifer phytoalexin brassinin. Bioorganic & Medicinal Chemistry, 14, 4958-4979.

Pedras, M. S. C.;* Chumala, P. B. 2006. Peptides and depsipeptides from plant pathogenic fungi. Handbook of Biologically Active Peptides, Abba Kastin, Ed., Elsevier, pp 1640. ISBN: 0-12-369442-6 (INVITED REVIEW).

Pedras, M. S. C.;* Suchy, M.; Ahiahonu, P. W. K. 2006. Unprecedented chemical structure and biomimetic synthesis of erucalexin, a phytoalexin from the wild crucifer Erucastrum gallicum. Organic & Biomolecular Chemistry, 4, 691-697.

Pedras, M. S. C.;* Okinyo, D. P. O. 2006. Syntheses of perdeuterated indoles and derivatives as probes for the biosyntheses of crucifer phytoalexins. Journal of Labelled Compounds & Radiopharmaceuticals, 49, 33-45.

Pedras, M. S. C.;* Suchy, M. 2006. Design, synthesis, evaluation and antifungal activity of inhibitors of brassilexin detoxification in the plant pathogenic fungus Leptosphaeria maculans. Bioorganic & Medicinal Chemistry, 14, 714-723.

Pedras, M. S. C.;* Jha, M.; Okeola, O. G. 2005. Camalexin Induces Detoxification of the Phytoalexin Brassinin in the Plant Pathogen Leptosphaeria maculans. Phytochemistry, 66, 2609-2616.

Pedras, M. S. C.;* Yu, Y.; Liu, J.; Tandron-Moya, Y. A. 2005. Metabolites produced by the phytopathogenic fungus Rhizoctonia solani: isolation, chemical structure determination, syntheses and bioactivity. Zeitschrift fur Naturforschung C, 60c, 717-722.

Pedras, M. S. C.;* Suchy, M. 2005. Detoxification pathways of the phytoalexins brassilexin and sinalexin in Leptosphaeria maculans: isolation and synthesis of the elusive intermediate 3-formylindolyl-2-sulfonic acid. Organic & Biomolecular Chemistry, 3, 2002-2007.

Pedras, M. S. C.;* Chumala, P. B.; Uppala, V. 2005. New sesquiterpenic phytotoxins establish unprecedented relationship between blackleg fungal isolates. Bioorganic & Medicinal Chemistry, 13, 2469-2475.

Pedras, M. S. C.;* Jha, M. 2005. Concise syntheses of the cruciferous phytoalexins brassilexin, sinalexin, wasalexins, and analogs: expanding the scope of the Vilsmeier formylation. Journal of Organic Chemistry, 70, 1828-1834.

Pedras, M. S. C.;* Ahiahonu, P. W. K. 2005. Metabolism and detoxification of phytoalexins and analogs by phytopathogenic fungi. Phytochemistry, 66, 391-411 (REVIEW).

Pedras, M. S. C.;* Chumala, P. B. 2005. Phomapyrones from new blackleg isolates: isolation, structure determination, biological activity and biosyntheses. Phytochemistry, 64, 81-87.

Pedras, M. S. C.;* Chumala, P. B.; Quail, J. W. 2004. Chemical mediators: the remarkable structure and host-selectivity of depsilairdin, a sesquiterpenic depsipeptide containing a new amino acid. Organic Letters, 6, 4615-4617.

Pedras, M. S. C.;* Hossain, M.; Sarwar, M. G.; Montaut, S. 2004. Determination of the enantiomeric purity of the phytoalexins spirobrassinins by 1H NMR using chiral solvation. Bioorganic & Medicinal Chemistry Letters, 14, 5469-5471.

Pedras, M. S. C. 2004. Prospects for controlling plant fungal diseases: alternatives based on chemical ecology and biotechnology. Canadian Journal of Chemistry, 82, 1329-1335. (Canadian Society for Chemistry, Clara Benson award lecture, INVITED).

Pedras, M. S. C.;* Ahiahonu, P. W. K.; Hossain, M. 2004. Detoxification of the cruciferous phytoalexin brassinin in Sclerotinia sclerotiorum requires an inducible glucosyltransferase. Phytochemistry, 65, 2685-2694.

Pedras, M. S. C.;* Ahiahonu, P. W. K. 2004. Phytotoxin production and phytoalexin elicitation by the phytopathogenic fungus Sclerotinia sclerotiorum. Journal of Chemical Ecology, 30, 2163 - 2179.

Gardiner, D. M.; Cozijnsen, A. J.; Wilson, L. M.; Pedras, M. S. C.; Howlett, B. J.* 2004. The sirodesmin biosynthetic gene cluster of the plant pathogenic fungus Leptosphaeria maculans. Molecular Microbiology, 53, 1307-1318.

Pedras, M. S. C.;* Montaut, S.; Suchy, M. 2004. New phytoalexins from rutabaga: structures, syntheses, biosyntheses, and biological activity. Journal of Organic Chemistry, 69, 4471-4476.

Pedras, M. S. C.;* Liu, J. 2004. Designer phytoalexins: probing camalexin detoxification pathways in the phytopathogen Rhizoctonia solani. Organic and Biomolecular Chemistry, 2, 1070-1076.

Pedras, M. S. C.;* Montaut, S. 2004. The biosynthesis of crucifer phytoalexins: unprecedented incorporation of a 1-methoxyindolyl precursor. Chemical Communications, 452-453.

Idnurm, A.; Taylor, J. L. Pedras, M. S. C.; Howlett, B. J.* 2003. Small scale functional genomics of the blackleg fungus Leptosphaeria maculans: analysis of a 38 kb region. Australasian Plant Pathology, 32 (4): 511-519.

Pedras, M. S. C.;* Jha, M.; Ahiahonu, P. W. K. 2003. The synthesis and biosynthesis of phytoalexins produced by cruciferous plants. Current Organic Chemistry 7, 1635-1647 (REVIEW).

Pedras, M. S. C.;* Montaut, S.; Zaharia, I. L.; Gai, Y.; Ward, D. E. 2003. Biotransformation of the Host-selective Toxin Destruxin B by Wild Crucifers: Probing a Detoxification Pathway. Phytochemistry, 64, 957-963.

Pedras, M. S. C.;* Chumala, P. B.; Suchy, M. 2003. Phytoalexins from Thlaspi arvense, a wild crucifer resistant to virulent Leptosphaeria maculans: structures, syntheses and antifungal activity. Phytochemistry, 64, 949-956.

Pedras, M. S. C.;* Montaut, S. 2003. Probing metabolic pathways in fungal pathogens of crucifers: biotransformation of indole-3-acetaldoxime, 4-hydroxyphenylacetaldoxime, and their metabolites. Bioorganic & Medicinal Chemistry, 11, 3115-3120.

Pedras, M. S. C.;* Ismail, N.; Quail, W.; Boyetchko, S. 2003. Structure, chemistry, and biological activity of pseudophomins A and B, a class of cyclic lipodepsipeptides isolated from the biocontrol bacterium Pseudomonas fluorescens. Phytochemistry, 62, 1105 - 1114.

Pedras, M. S. C.;* Ahiahonu, P. W. K. 2002. Probing the phytopathogenic stem rot fungus with phytoalexins and analogs: unprecedented glucosylation of camalexin and 6-methoxycamalexin. Bioorg. Med. Chem., 10, 3307-3312.

Pedras, M. S. C.;* Nycholat, C. M.; Montaut, S.; Xu, Y.; Khan, A. K. 2002. Chemical defenses of crucifers: elicitation and metabolism of phytoalexins and indole-3-acetonitrile in brown mustard and turnip. Phytochemistry, 59, 611-625.

Pedras, M. S. C.;* Zaharia, I. L.; Ward, D. E. 2002. The destruxins: synthesis, biosynthesis, biotransformation, and biological activity. Phytochemistry, 59, 579-596. (REVIEW)

Ward, D. E.;* Gai, Y.; Lazny, R.; Pedras, M. S. C.* 2001. Probing host-selective phytotoxicity: synthesis of natural analogs of the host-selective toxin destruxin B. Journal of Organic Chemistry, 66,7832-7840.

Pedras, M. S. C.;* Biesenthal, C. J. 2001. Secondary metabolites from the phytopathogenic fungus Phoma lingam: detection, isolation, structure determination, and phytotoxicity of unusual dioxopiperazines. Phytochemistry, 58, 905-909.

Pedras, M. S. C.;* Montaut, S.; Xu, Y; Khan, A. Q.; Loukaci, A. 2001. Assembling the biosynthetic puzzle of crucifer metabolites: indole-3-acetaldoxime is incorporated efficiently into phytoalexins but glucobrassicin is not. Chemical Communications, 1572-1573.

Pedras, M. S. C. 2001. Phytotoxins from fungi causing blackleg disease on crucifers: isolation, structure determination, detection, and phytotoxic activity. Recent Research Developments in Phytochemistry, 5, 109-117 (REVIEW).

Howlett B. J.;* Idnurm A.; Pedras M. S. C. 2001. Leptosphaeria maculans the causal agent of blackleg disease of brassicas. Fungal Genetics and Biology, 33, 1-14 (REVIEW).

Pedras, M. S. C.;* Zaharia, I. L. 2001. Unprecedented Vilsmeier formylation: expedient synthesis of the cruciferous phytoalexin sinalexin and discovery of a new heteroaromatic ring system. Organic Letters, 3, 1213-1216.

Pedras, M. S. C.;* Zaharia, I.L.; Gai, Y.; Zhou, Y.; Ward, D. E. 2001. In planta sequential hydroxylation and glycosylation of a fungal phytotoxin: avoiding cell death and overcoming the fungal invader. Proceedings of the National Academy Sciences, USA, 98 747-752.

Pedras, M. S. C.;* Zaharia, I. L. 2000. Sinalbins A and B, phytoalexins from Sinapis alba: elicitation, isolation, and synthesis. Phytochemistry, 55, 213-216.

Pedras, M. S. C.;* Biesenthal, C. J. 2000. Vital staining of plant cell suspension cultures: evaluation of the phytotoxic activities of the phytotoxins phomalide and destruxin B. Plant Cell Reports, 19, 1135-1138.

Pedras, M. S. C.;* Biesenthal, C. J. 2000. HPLC Analyses of cultures of Phoma species: differentiation among groups and species through secondary metabolite profiles. Canadian Journal of Microbiology, 46, 685-691.

Pedras, M. S. C.;* Biesenthal, C. J.; Zaharia, I. L. 2000. Comparison of the phytotoxic activity of the phytotoxin destruxin b and four natural analogs. Plant Science, 156, 185-192.

Pedras, M. S. C.;* Okanga F. I. 2000. Metabolism of Analogs of the Phytoalexin Brassinin by Plant Pathogenic Fungi. Canadian Journal of Chemistry, 78, 338-346.

Pedras, M. S. C.;* Okanga, F. I.; Zaharia, I. L; Khan, A. Q. 2000. Phytoalexins from crucifers: synthesis, biosynthesis, and biotransformation. Phytochemistry, 53, 161-176. (REVIEW).

Pedras, M. S. C.;* Khan, A. Q. 2000. Biotransformation of the phytoalexin camalexin by the root phytopathogen Rhizoctonia solani. Phytochemistry, 53, 59-69.

Pedras, M. S. C.;* Erosa-Lopez, C. C.; Quail, J. W.; Taylor, J. L. 1999. Phomalairdenone, a new host-selective phytotoxin from a virulent type of the blackleg fungus Phoma lingam. Bioorganic & Medicinal Chemistry Letters, 9, 3291-3294.

Pedras, M. S. C.;* Zaharia, I.L.; Gai, Y.; Smith, K. C.; Ward, D. E.* 1999. Metabolism of the host-selective toxins destruxin b and homodestruxin b: probing a plant disease resistance trait. Organic Letters, 1, 1655-1658.

Pedras, M. S. C. ;* Sorensen, J. L.; Okanga, F. I.; Zaharia, I. L. 1999. Wasalexins A and B, new phytoalexins from wasabi: isolation, synthesis, and antifungal activity. Bioorganic & Medicinal Chemistry Letters, 9, 3015-3020.

Pedras, M. S. C.;* Okanga, F. I. 1999. Strategies of cruciferous pathogenic fungi: detoxification of the phytoalexin cyclobrassinin by mimicry. Journal of Agricultural & Food Chemistry, 47, 1196-1202.

Ward, D. E.;* Vazquez, A.; Pedras, M. S. C.* 1999. Probing host-selective phytotoxicity: synthesis and biological activity of phomalide, isophomalide and dihydrophomalide. Journal of Organic Chemistry, 67, 1657-1666.

Pedras, M. S. C.;* Khan, A.Q.; Taylor, J. L. 1998. The phytoalexin camalexin is not metabolized by Phoma lingam, Alternaria brassicae, or phytopathogenic bacteria. Plant Science, 139, 1-8.

Pedras, M. S. C.;* Loukaci, A.; Okanga F. I. 1998. The Cruciferous Phytoalexins Brassinin and Cyclobrassinin Are Intermediates in The Biosynthesis of Brassilexin. Bioorganic & Medicinal Chemistry Letters, 8, 3037-3038.

Pedras, M. S. C.;* Okanga, F. I . 1998. A Convenient Synthesis of the Cruciferous Phytoalexins Brassicanal A and Brassilexin by Mimicry of a Fungal Detoxification Pathway. Chemical Communications, 1565-1566.

Pedras, M. S. C.;* Sorensen, J. L. 1998. Phytoalexin Accumulation and Production of Antifungal Compounds by the Crucifer Wasabi. Phytochemistry, 49, 1959-1965.

Pedras, M. S. C. 1998. Phytoalexins from crucifers: mimicking or overcoming plant chemical defenses? Recent Research Developments in Phytochemistry, 2, 259-267. (REVIEW)

Pedras, M. S. C.;* Smith, K. C.; Taylor, J. L. 1998. Production of a 2,5-dioxopiperazine by a new isolate type of the blackleg fungus Phoma lingam. Phytochemistry, 49, 1575-1577.

Pedras, M. S. C.;* Biesenthal, C. J. 1998. Production of the host-selective toxin phomalide by isolates of Leptosphaeria maculans and its correlation with sirodesmin PL production. Canadian Journal of Microbiology 44, 547-553.

Pedras, M. S. C. 1998. Towards an Understanding and Control of Plant Fungal Diseases in Brassicaceae, Recent Research Developments in Agricultural and Food Chemistry, 2, 513-532 (REVIEW).

Pedras, M. S. C.;* Okanga, F. I. 1998. Probing the phytopathogenic blackleg fungus with a phytoalexin homolog. Journal of Organic Chemistry, 63, 416-417.

Pedras, M. S. C.;* Okanga, F. I. 1998. Strategies of Fungal Pathogens: Detoxification of a Cruciferous Phytoalexin by Mimicry. Chemical Communications, 67-68.

Pedras, M. S. C.;* Smith, K. C. 1997. Sinalexin, a phytoalexin from white mustard elicited by destruxin B and Alternaria brassicae, Phytochemistry, 46, 833-837.

Pedras, M. S. C.;* Khan, A. Q. 1997. Unprecedented Detoxification of the Phytoalexin Camalexin by a Root Rot Pathogen, Bioorganic & Medicinal Chemistry Letters, 7, 2255-2260.

Pedras, M. S. C.;* Khan, A. Q.; Smith, K. C.; Stettner, S. L. 1997. Preparation, biotransformation, and antifungal activity of methyl benzyldithiocarbamates. Canadian Journal of Chemistry, 75, 825-828.

Pedras, M. S. C. 1997. Determination of the absolute configuration of the fragments composing phomalide. Canadian Journal of Chemistry, 75, 314-317.

Ward, D. E.;* Lazny, R.; Pedras, M. S. C.* 1997. Synthesis of the host-selective phytotoxin destruxin B. Avoiding diketopiperazine formation from an N-methyl amino acid dipeptide by use of the Boc-hydrazide derivative. Tetrahedron Letters, 38, 339-342.

Pedras, M. S. C.;* Khan, A.Q.; Taylor, J.L. 1997. Phytoalexins from Brassicas: overcoming plants' defenses. In Phytochemicals for Pest Control; Hedin, P. A.; Hollingworth, R. M.; Masler, E. P.; Miyamoto, J.; Thompson, D. G. Eds.; ACS Symposium Series 658, 155-166 (REVIEW).

Pedras, M. S. C. 1996. Phytotoxins from phytopathogenic blackleg fungi. Revista Latinoamericana de Quimica, 24, 177-182 (REVIEW).

Ward, D. E.;* Vazquez, A.; Pedras, M. S. C.* 1996. Understanding host-selective phytotoxicity: synthesis and biological discrimination of phomalide and its (Z)-isomer. Journal of Organic Chemistry, 61, 8008-8009.

Pedras, M. S. C.;* Khan, A. Q. 1996. Biotransformation of the Brassica Phytoalexin Brassicanal A by the Blackleg Fungus, Journal of Agricultural & Food Chemistry, 44, 3403-3407.

Pedras, M. S. C. 1996. The chemistry of cyclohexenediones produced by the blackleg fungus. Canadian Journal of Chemistry, 74, 1597-1601.

Pedras, M. S. C.;* Taylor, J. L.; Morales, V. M. 1996. The blackleg fungus of rapeseed: how many species? Acta Horticulturae, 407, 441-446 (REVIEW).

Taylor, J. L.;* Pedras, M. S. C.; Morales, V. M. 1995. Horizontal transfer in the phytopathogenic fungal genus Leptosphaeria and its correlation to host-range expansion. Trends in Microbiology, 3, 202-206.

Pedras, M. S. C.;* Taylor, J.L.; Morales, V. M. 1995. Phomaligin A and other yellow pigments in Phoma lingam and P. wasabiae. Phytochemistry, 38, 1215-1222.

Pedras, M. S. C.;* Morales, V. M.; Taylor, J. L. 1994. Phomapyrones: three metabolites from the "blackleg" fungus. Phytochemistry, , 36, 1315-1318.

Pedras, M. S. C.;* McAfee, B. J.; Lapp, M. S. 1994. Biotransformation of 1-naphthaleneacetic acid by the ectomycorrhizal fungus Pisolithus arhizus. Phytochemistry, 36, 825-827.

Pedras, M. S. C.;* Taylor, J. L.; Nakashima, T. T. 1993. A novel chemical signal from the blackleg fungus: beyond phytotoxins and phytoalexins. Journal of Organic Chemistry, 58, 4778-4780.

Pedras, M. S. C.;* Morales, V. M.; Taylor, J. L. 1993. Phomaligols and phomaligadiones: new metabolites from the blackleg fungus. Tetrahedron, 37, 8317-8322.

Pedras, M. S. C.;* Taylor, J. L. 1993, Metabolism of the phytoalexin brassinin by the 'blackleg fungus'. Journal of Natural Products, 56, 731-738.

Pedras, M. S. C.;* Borgmann, I.; Taylor, J. L. 1992. Biotransformation of brassinin is a detoxification mechanism in the 'blackleg" fungus. Life Science Advances (Phytochemistry), 11, 1-7. (INVITED)

Pedras, M. S. C.;* Seguin-Swartz, G. 1992. The "blackleg" fungus: phytotoxins and phytoalexins. Canadian Journal of Phytopathology, 14, 67-75. (REVIEW)

Pedras, M. S. C.;* Taylor, J. L. 1991. Metabolic transformation of the phytoalexin brassinin by the 'blackleg fungus'. Journal of Organic Chemistry, 56, 2619-2621.

Kao, K. N.;* Saleem, M.; Abrams, S.; Pedras, S.; Horn, D.; Mallard, C. 1991. Culture conditions for induction of green plants from barley microspores by anther culture methods. Plant Cell Reports, 9, 595-607.

Pedras, M. S. C.* Seguin-Swartz 1990. Rapid high-performance liquid chromatographic analysis of phytotoxins from Phoma lingam. J. Chromatography, 519, 383-386.

Pedras, M. S. C.;* Seguin-Swartz, G.; Abrams, S. R. 1990. Minor phytotoxins from the blackleg fungus Phoma lingam. Phytochemistry, 29, 777-782.

Pedras, M. S. C.;* Abrams, S.R.; Seguin-Swartz, G.; Quail, J.W.; Jia, Z. 1989. Phomalirazine, a novel toxin from the phytopathogenic fungus Phoma lingam. Journal of the American Chemistry Society, 111, 1904-1905.

Pedras, M. S. C.;* Abrams, S.R.; Seguin-Swartz, G. 1988. Isolation of the first naturally occurring epimonothiodioxopiperazine, a fungal toxin produced by Phoma lingam. Tetrahedron Letters, 29, 3471-3474.

Ayer, W. A.;* Pedras, M. S. C.; Ward, D. E. 1987. Metabolites produced by the scleroderris canker fungus Gremmeniella abietina. Part 4. Biosynthetic studies. Canadian Journal of Chemistry, 65, 760-764. (PhD. project)

Ayer, W. A.;* Pedras, M. S. C. 1987. Metabolites produced by the scleroderris canker fungus Gremmeniella abietina. Part 3. Some further metabolites. Canadian Journal of Chemistry, 65, 754-759. (PhD. project)

Ayer, W. A.;* Hoyano, Y.; Pedras, M. S. C.; Clardy, J.; Arnold, E. 1987. Metabolites produced by the scleroderris Canker Fungus Gremmeniella abietina. Part 2. The structure of scleroderolide. Canadian Journal of Chemistry, 65, 748-753. (PhD. project)

Ayer, W. A.;* Hoyano, Y.; Pedras, M. S. C.; van Altena, I. 1986. Metabolites produced by the scleroderris canker fungus Gremmeniella abietina. Part 1. Canadian Journal of Chemistry, 64, 1585-1589. (Ph.D. project)

 

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