Isolation of bacteria from fruiting bodies of Rhizopogon roseolus and their effect on mycelial growth of host mushroom

Abstract

Rhizopogon roseolus (Corda) Th. M. Fr. is an edible ectomycorrhizal mushroom. Bacterial strains promoting the development of mycorrhizal symbiosis have been frequently isolated from mycorrhizospheres. Recently, we isolated certain bacteria from fruiting bodies of R. roseolus and observed that the bacteria could stimulate mycelial growth. In this study, we isolated various bacteria from fruiting bodies and investigated their effect on mycelial growth of R. roseolus using a co-culture method. Among nineteen cultivable bacterial strains from the fruiting body of R. roseolus, six bacterial strains specifically stimulated the mycelial growth of R. roseolus. Blast analysis revealed that the bacterial strains belonged to the genera Paraburkholderia, Caballeronia, Janthinobacterium, Novosphingobium and Rhodobacter. Ultrastructure morphologies of the dominant three strains were revealed by scanning electron microscopic observation. These results indicate the possible involvement of specific bacteria on fruiting body formation of R. roseolus.