Effects of imidazole-4-carboxamide and 2-azahypoxanthine on the growth and ectomycorrhizal colonization of Pinus densiflora seedlings inoculated with Tricholoma matsutake

Abstract

Imidazole-4-carboxamide (ICA) and 2-azahypoxanthine (AHX) obtained from Lepista sordida inhibit and promote the growth of herbaceous plants, respectively. In this study, we examined the effects of these compounds on the growth and ectomycorrhizal (EM) colonization of Pinus densiflora seedlings inoculated with Tricholoma matsutake that forms EM associations with pines. The EM colonization by T . matsutake was observed on the root systems of P . densiflora seedlings treated with and without ICA and AHX. The growth of both non-EM and EM P . densiflora seedlings was inhibited by ICA, regardless of the EM colonization. In contrast, AHX promoted the growth of non-EM P . densiflora seedlings, but not of EM seedlings, suggesting that EM colonization interferes with the effect of AHX on P . densiflora growth. • Imidazole-4-carboxamide (ICA) and 2-azahypoxanthine (AHX) are bioactive compounds. • Tricholoma matsutake – Pinus densiflora ectomycorrhizal (EM) seedlings were tested. • Growth of both non-EM and EM P. densiflora seedlings was inhibited by ICA. • Growth of non-EM P. densiflora was promoted by AHX; EM seedlings were unaffected. • EM colonization interfered with the growth promotion of AHX on P. densiflora.