Epiphytic Bacteria Associated with the Bryophyte Funaria hygrometrica: Effects of Methylobacterium Strains on Protonema Development

Abstract: Bacteria represent a substantial fraction of the microorganisms that inhabit leaf surfaces. We collected samples of the moss Funaria hygrometrica (L.) in the field and analysed the epiphytes on the gametophyte by the agar impression method and scanning electron/fluorescence microscopy. On the phylloid surface numerous bacteria were detected, notably in the grooves between adjacent lamina cells. Methanol-ammonium salts agar surfaces impressed with isolated phylloids of green gametophytes resulted in the growth of methylotrophic colonies. Two Methylobacterium strains ( M. mesophilicum and M. sp., isolated from the Funaria phylloids) were found to simulate the well-known effect of cytokinin application on bud formation in Funaria protonemata. In addition, Methylobacterium inoculation promoted the growth of protonemal filaments. The significance of this novel Methylobacterium -land plant interaction is discussed.