title: Transcriptional responses to sucrose mimic the plant-associated life style of the plant growth promoting endophyte Enterobacter sp. 638.
abstract: Growth in sucrose medium was previously found to trigger the expression of functions involved in the plant associated life style of the endophytic bacterium Enterobacter sp. 638. Therefore, comparative transcriptome analysis between cultures grown in sucrose or lactate medium was used to gain insights in the expression levels of bacterial functions involved in the endophytic life style of strain 638. Growth on sucrose as a carbon source resulted in major changes in cell physiology, including a shift from a planktonic life style to the formation of bacterial aggregates. This shift was accompanied by a decrease in transcription of genes involved in motility (e.g., flagella biosynthesis) and an increase in the transcription of genes involved in colonization, adhesion and biofilm formation. The transcription levels of functions previously suggested as being involved in endophytic behavior and functions responsible for plant growth promoting properties, including the synthesis of indole-acetic acid, acetoin and 2,3-butanediol, also increased significantly for cultures grown in sucrose medium. Interestingly, despite an abundance of essential nutrients transcription levels of functions related to uptake and processing of nitrogen and iron became increased for cultures grown on sucrose as sole carbon source. Transcriptome data were also used to analyze putative regulatory relationships. In addition to the small RNA csrABCD regulon, which seems to play a role in the physiological adaptation and possibly the shift between free-living and plant-associated endophytic life style of Enterobacter sp. 638, our results also pointed to the involvement of rcsAB in controlling responses by Enterobacter sp. 638 to a plant-associated life style. Targeted mutagenesis was used to confirm this role and showed that compared to wild-type Enterobacter sp. 638 a ΔrcsB mutant was affected in its plant growth promoting ability.
authors.affiliation: Center for Agricultural and Environmental Biotechnology, RTI International, Research Triangle Park, North Carolina, United States of America; Biosciences Department, Brookhaven National Laboratory, Upton, New York, United States of America.
authors.forename: Safiyh
authors.initials: S
authors.lastname: Taghavi
authors.affiliation: Biosciences Department, Brookhaven National Laboratory, Upton, New York, United States of America; Department of Applied Mathematics & Statistics, State University of New York, Stony Brook, New York, 11794-3600, United States of America.
authors.forename: Xiao
authors.initials: X
authors.lastname: Wu
authors.affiliation: Center for Agricultural and Environmental Biotechnology, RTI International, Research Triangle Park, North Carolina, United States of America; State Key Laboratory of Bioreactor Engineering, School of Biotechnology, East China University of Science and Technology, Shanghai, 200237, China.
authors.forename: Liming
authors.initials: L
authors.lastname: Ouyang
authors.affiliation: Biosciences Department, Brookhaven National Laboratory, Upton, New York, United States of America.
authors.forename: Yian Biao
authors.initials: YB
authors.lastname: Zhang
authors.affiliation: Biosciences Department, Brookhaven National Laboratory, Upton, New York, United States of America.
authors.forename: Andrea
authors.initials: A
authors.lastname: Stadler
authors.affiliation: Biosciences Department, Brookhaven National Laboratory, Upton, New York, United States of America.
authors.forename: Sean
authors.initials: S
authors.lastname: McCorkle
authors.affiliation: Department of Applied Mathematics & Statistics, State University of New York, Stony Brook, New York, 11794-3600, United States of America.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhu
authors.affiliation: Biosciences Department, Brookhaven National Laboratory, Upton, New York, United States of America.
authors.forename: Sergei
authors.initials: S
authors.lastname: Maslov
authors.affiliation: Center for Agricultural and Environmental Biotechnology, RTI International, Research Triangle Park, North Carolina, United States of America; Center for Agricultural and Environmental Biotechnology, RTI International, Research Triangle Park, North Carolina, United States of America.
authors.forename: Daniel
authors.initials: D
authors.lastname: van der Lelie
mesh_terms: D004754:Enterobacter / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D010944:Plants / Q000382:microbiology; D013395:Sucrose / Q000378:metabolism*
chemical_list: D013395:Sucrose