Mendel University in Brno 

What is the effect of seed treatment with Pythium oligandrum on the metabolism of rape plants?

Ryšlavá H [a], Bělonožníková K [a], Vaněk T [b], Vaverová K [a], Vaňková R [c], Křížek T [d], Hýsková V [a]

[a] Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, Prague 2, 128 43, Czech Republic
[b] Biopreparáty, spol. s r.o., Tylišovská 1, Praha 6, 160 00, Czech Republic
[c] Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Rozvojová 263, Praha 6, 165 02, Czech Republic
[d] Department of Analytical chemistry, Faculty of Science, Charles University, Hlavova 2030, Praha 2, 128 43, Czech Republic

Pythium oligandrum is a soil oomycete, which acts as a mycoparasite and thus protects plants from fungal pathogens. P. oligandrum interacts also with plant roots, activates plant defense response to pathogens, it functions as priming. In addition, P. oligandrum could synthetize auxin precursors and thus stimulate plant growth. In this study, we have treated rape seeds with several P. oligandrum isolates and tested metabolic changes in plants. Seed germination was not affected by P. oligandrum treatment. The growth parameters and photosynthetic pigment content of three-week rape plants were very similar to control plants. There were no significant differences in the soluble protein content, but the level of free aromatic amino acids, especially tryptophan, was lower in all plants treated with P. oligandrum isolates, while the glutamine content remained constant. Since it did not change the content of extractable phenolic compounds in all the plant groups, the aromatic amino acids could serve to synthesize lignin that is localized in the cell walls. Tryptophan seems to be an auxin precursor, because several isolates of P. oligandrum actually increased indole acetic acid concentrations in plants. Other differences were found in salicylic acid, jasmonate and ethylene concentrations. Further studies will be necessary to assess the response of plants to a pathogen infection and to evaluate their success as a biological control agents.