ascorbigen and 1--methylascorbigen

The effect of ascorbigen and 1'-methylascorbigen on the disease resistance of bean (Phaseolus vulgaris L.,. cv. Debreceni Tarka) to the fungal pathogen Uromyces phaseoli Pers. is reported. Contrary to ascorbigen, pretreatment of bean plants with l'-methylascorbigen, as in the case of other endogenous N-, O- and S-methyl compounds, induced the double immune response leading to the biochemical immunization of plants. The effectiveness of protection depended on the dosage of the applied l'-methylascorbigen and on the time interval between the chemical pretreatment and inoculation. Results of our greenhouse experiments revealed, in accordance with previous results, that the presence of the N-methyl group in the 1'-methylascorbigen molecule is the precondition of the effect, and formaldehyde formed from this N-methyl group and its reaction products (e.g. singlet oxygen, ozone) can have a determining role in the manifestation of the effect.

Topics: Ascorbic Acid; Basidiomycota; Immunity, Innate; Indoles; Phaseolus; Plant Diseases; Time Factors

The effect of ascorbigen and 1'-methylascorbigen as a model compound pair was studied on the phytopathogenic bacterium Pseudomonas savastanoi pv. phaseolicola in the BioArena experimental system after overpressured layer chromatography. Results showed a characteristic, strong antibacterial effect of 1'-methylascorbigen and weak effect of ascorbigen present on the adsorbent layer as chromatographic spot. Addition of formaldehyde capture compounds (L-arginine, glutathione, dimedone) partially or totally reduced the antibacterial effect of 1'-methylascorbigen and ascorbigen. On adding Cu(II) ions--which mobilize and coordinate formaldehyde--to the culture medium, the antibacterial effect of both compounds became stronger. It is supposed that the weak antibacterial effect of ascorbigen may have originated from the 1'-methylascorbigen formed in situ on the adsorbent layer by partial enzymatic methylation of ascorbigen.

Topics: Anti-Bacterial Agents; Arginine; Ascorbic Acid; Chromatography, Thin Layer; Copper; Cyclohexanones; Formaldehyde; Glutathione; Indoles; Pseudomonas