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Abstract

Plant materials are sustainable substrates supporting new technologies of plant-only-based culture media for in vitro culturing of the plant microbiota

In order to improve the culturability and biomass production of rhizobacteria, we previously introduced plant-only-based
culture media. We herein attempted to widen the scope of plant materials suitable for the preparation of plant-only-based culture
media. We chemically analyzed the refuse of turfgrass, cactus, and clover. They were sufficiently rich to support good in vitro
growth by rhizobacteria isolates representing Proteobacteria and Firmicutes. They were also adequate and efficient to produce
a cell biomass in liquid batch cultures. These culture media were as sufficient as artificial culture media for the cultivation and
recovery of the in situ rhizobacteria of barley (Hordeum murinum L.). Based on culture-dependent (CFU plate counting) and
culture-independent analyses (qPCR), mowed turfgrass, in particular, supported the highest culturable population of barley
endophytes, representing >16% of the total bacterial number quantified with qPCR. This accurately reflected the endophytic
community composition, in terms of diversity indices (S’, H’, and D’) based on PCR-DGGE, and clustered the plant culture
media together with the qPCR root populations away from the artificial culture media. Despite the promiscuous nature of the
plant materials tested to culture the plant microbiome, our results indicated that plant materials of a homologous nature to the
tested host plant, at least at the family level, and/or of the same environment were more likely to be selected. Plant-only-based
culture media require further refinements in order to provide selectivity for the in vitro growth of members of the plant microbiome,
particularly difficult-to-culture bacteria. This will provide insights into their hidden roles in the environment and support future
culturomic studies.



Mourad, E.F.; Sarhan, M.S.; Daanaa, H-S.A.; Abdou, M.; Morsi A.T.; Abdelfadeel, M.R.; Elsawey, R.; El-Tahan, M.; Hamza, M.A.; Abbas, M.; Youssef, H.H.; Abdelhadi, A.A.; Amer W.M.; Fayez, M.; Ruppel, S.; Hegazi, N. 2018. Plant materials are sustainable substrates supporting new technologies of plant-only-based culture media for in vitro culturing of the plant microbiota. Microbes and Environments 33, 40-49.

DOI: 10.1264/jsme2.ME17135