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The effects of viral infection on plant cell phenolics in wheat and tobacco

University of British Columbia

The study compared the effects on free and cell wall bound phenolics of Triticum aestivum cv. Katepwa inoculated with Tobacco Necrosis Virus (TNV), Barley Stripe Mosaic Virus (BSMV) or distilled water. In addition, the phenolic compounds in Nicotiana tabacum cv. Xanthi n.c. inoculated with TNV, Tobacco Mosaic Virus or distilled water were examined. Analysis of the free phenolics consisted of methanol extracts of freeze-dried plant leaves. Samples of the methanol extracts were subjected to hydrolysis by NaOH and B-glucosidase. Cell wall bound phenolics were determined from hydrolysis of the cell walls with 2 M NaOH. Identification and separation of the various phenolic compounds was attained by use of HPLC. In unhydrolysed wheat methanol extracts, no phenolics were identified. In the tobacco samples, protocatechuic acid was found in mock samples. In J3-glucosidase hydrolysed wheat samples ferulic acid was found in both virally challenged treatments but not in mock inoculated plants. In the tobacco, TMV infected samples contained vanillic, caffeic, salicylic, ferulic and possibly truxinic or truxillic acids. In TNV inoculated samples 4-hydroxybenzoic acid was found. Mock samples contained no identifiable peaks. Alkali hydrolysis methanol extracts contained vanillic, caffeic, benzoic, salicylic and truxinic/truxillic acids. In the TNV infected plants benzoic acid was identified. No compounds were identified in mock inoculated samples. Wheat cell walls released vanillic, p-coumaric, ferulic, and diferulic acids as well as vanillin and p-hydroxybenzaldehyde. Levels released decreased late in the infection process The mock infected tobacco cell walls released p-coumaric acid. The TNV inoculated samples released p-hydroxybehzaldehyde and vanillin as well as p-coumaric acid. The TMV exposed plants produced caffeic acid in addition to the compounds produced by TNV.

Thesis/Dissertation

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2009-02-06

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http://hdl.handle.net/2429/4203

Botany

University of British Columbia

UBCV

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