title: Enhanced performance of the microalga Chlorella sorokiniana remotely induced by the plant growth-promoting bacteria Azospirillum brasilense and Bacillus pumilus.
abstract: Remote effects (occurring without physical contact) of two plant growth-promoting bacteria (PGPB) Azospirillum brasilense Cd and Bacilus pumilus ES4 on growth of the green microalga Chlorella sorokiniana UTEX 2714 were studied. The two PGPB remotely enhanced the growth of the microalga, up to six-fold, and its cell volume by about three-fold. In addition to phenotypic changes, both bacteria remotely induced increases in the amounts of total lipids, total carbohydrates, and chlorophyll a in the cells of the microalga, indicating an alteration of the microalga's physiology. The two bacteria produced large amounts of volatile compounds, including CO2, and the known plant growth-promoting volatile 2,3-butanediol and acetoin. Several other volatiles having biological functions in other organisms, as well as numerous volatile compounds with undefined biological roles, were detected. Together, these bacteria-derived volatiles can positively affect growth and metabolic parameters in green microalgae without physical attachment of the bacteria to the microalgae. This is a new paradigm on how PGPB promote growth of microalgae which may serve to improve performance of Chlorella spp. for biotechnological applications.
authors.affiliation: Environmental Microbiology Group, Northwestern Center for Biological Research (CIBNOR), Av IPN 195, La Paz, B.C.S. 23096, Mexico.
authors.forename: Edgar
authors.initials: E
authors.lastname: Amavizca
authors.affiliation: Environmental Microbiology Group, Northwestern Center for Biological Research (CIBNOR), Av IPN 195, La Paz, B.C.S. 23096, Mexico.|The Bashan Institute of Science, 1730 Post Oak Court, Auburn AL 36830, USA.|Dept. of Entomology and Plant Pathology, 301 Funchess Hall, Auburn Univ., Auburn, AL 36849, USA.
authors.forename: Yoav
authors.initials: Y
authors.lastname: Bashan
authors.affiliation: Molecular Phytobacteriology Laboratory, Korean Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 305-600, South Korea.
authors.forename: Choong-Min
authors.initials: CM
authors.lastname: Ryu
authors.affiliation: Department of Pharmacognosy, Faculty of Pharmacy, Cairo University, Cairo 11562, Egypt.
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Farag
authors.affiliation: Exobiology Branch, NASA Ames Research Center, Moffett Field, CA 94035, USA.
authors.forename: Brad M
authors.initials: BM
authors.lastname: Bebout
authors.affiliation: Environmental Microbiology Group, Northwestern Center for Biological Research (CIBNOR), Av IPN 195, La Paz, B.C.S. 23096, Mexico.|The Bashan Institute of Science, 1730 Post Oak Court, Auburn AL 36830, USA.|Dept. of Entomology and Plant Pathology, 301 Funchess Hall, Auburn Univ., Auburn, AL 36849, USA.
authors.forename: Luz E
authors.initials: LE
authors.lastname: de-Bashan
mesh_terms: D015806:Azospirillum brasilense / Q000187:drug effects / Q000502:physiology*; D000069979:Bacillus pumilus / Q000187:drug effects / Q000502:physiology*; D050260:Carbohydrate Metabolism / Q000187:drug effects; D002245:Carbon Dioxide / Q000378:metabolism; D002708:Chlorella / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D004926:Escherichia coli / Q000378:metabolism; D050356:Lipid Metabolism / Q000187:drug effects; D058086:Microalgae / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D055549:Volatile Organic Compounds / Q000494:pharmacology
chemical_list: D055549:Volatile Organic Compounds; D002734:Chlorophyll; D002245:Carbon Dioxide; D000077194:Chlorophyll A