Suppression of the take-all fungus (Gaeumannomyces graminis var. tritici) by a sterile red fungus through induced resistance in wheat (Triticum aestivum) seedling roots

The aim of this study was to verify that induced resistance was another mechanism through which a sterile red fungus (SRF) can suppress Gaeumannomyces graminis (Sacc.) Arx and Olivier var. tritici (Walker) (Ggt). Using a split-root system, it was expected that prior inoculation of one half of the wheat (Triticum aestivum L cv. Gamenya) seedling roots with the SRF 0 or 7 d prior to inoculation with Ggt to the remaining roots in the other pot would result in the suppression of Ggt infection through the induction of host defence mechanisms by the SRF. The split-root system was set up with six treatments: (i) no Ggt or the SRF inoculum; (ii) sterilised Ggt inoculum only; (iii) Ggt only; (iv) the SRF only; (v) the SRF and Ggt inoculated on the same day; and (vi) Ggt added 7 d after the SRF. Fresh shoot and root weight (g), root length (m), lesion length (cm) and percentage effective root length were measured 21 d after prior inoculation with SRF. Shoot and root growth were stimulated by the SRF as expected from previous studies. Lesion length was significantly (P<0.05) reduced in the SRF pre-inoculated plants compared to the control by virtue of both reduction in lesion length and rate of lesion development. Similar results were observed for effective root length measurements. It was thus concluded that induced host resistance was another mechanism by which the SRF can suppress Ggt infection systemically in wheat seedling roots.