Effects of ectomycorrhizal fungi on damping-off and induction of pathogenesis-related proteins in Pinus tabulaeformis seedlings inoculated with Amanita vaginata.

Summary The formation of mycorrhiza on Pinus tabulaeformis (Pt) seedlings by ectomycorrhizal fungi (ECMF), the protective effect of the ECMF on damping-off caused by Rhizoctonia solani and the expression of pathogenesis-related proteins (PR-proteins) induced by Amanita vaginata and/or R. solani in Pt seedlings were investigated. The results indicated that: (i) among the 10 ECMF tested, five species ( Gomphidius viscidus, Suillus laricinus, Suillus tomentosus, A. vaginata and Basidiomycetes no. 058) formed mycorrhiza with Pt seedlings. There was a positive correlation between mycorrhizal colonization levels and protective effects ( r = 0.9207). Among the five species, A. vaginata had the highest colonization level and the best protective effect against damping-off; however, G. viscidus had no protective effect even though it had a high mycorrhization level. (ii) Chitinases, β-1,3-glucanases and PR-proteins in the seedlings were not induced by A. vaginata colonization, but were induced when A. vaginata-mycorrhizal seedlings were attacked by R. solani. It is possible that chitinases, β-1,3-glucanases and 108, 97, 78, 44, 37 and 14-kDa PR-proteins induced both by A. vaginata and R. solani protect Pt seedlings from R. solani infection. [ABSTRACT FROM AUTHOR]