title: Accumulation of intra-cellular polyphosphate in Chlorella vulgaris cells is related to indole-3-acetic acid produced by Azospirillum brasilense.
abstract: Accumulation of intra-cellular phosphate, as polyphosphate, was measured when the microalga Chlorella vulgaris was immobilized in alginate with either of two wild-type strains of the microalgae growth-promoting bacterium Azospirillum brasilense or their corresponding IAA-attenuated mutants. Wild type strains of A. brasilense induced higher amounts of intra-cellular phosphate in Chlorella than their respective mutants. Calculations comparing intra-cellular phosphate accumulation by culture or net accumulation by the cell and the amount of IAA that was produced by each of these strains revealed that higher IAA was linked to higher accumulations of intra-cellular phosphate. Application of four levels of exogenous IAA reported for A. brasilense and their IAA-attenuated mutants to cultures of C. vulgaris enhanced accumulation of intra-cellular phosphate; the higher the content of IAA per culture or per single cell, the higher was the amount of accumulated phosphate. When an IAA-attenuated mutant was complemented with exogenous IAA, accumulation of intra-cellular phosphate at the culture level was even higher than phosphate accumulation with the respective wild type strains. When calculating the net accumulation of intra-cellular phosphate in the complementation experiment, net intra-cellular phosphate induced by the IAA-attenuated mutant was completely restored and was similar to the wild strains. We propose that IAA produced by A. brasilense is linked to polyphosphate accumulation in C. vulgaris.
authors: Environmental Microbiology Group, Northwestern Center for Biological Research (CIBNOR), Av. IPN #195, La Paz, B.C.S. 23096, Mexico.
authors: Beatriz
authors: B
authors: Meza
authors: 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, 209 Life Sciences Building, Auburn Univ., Auburn, AL 36849, USA.
authors: Luz E
authors: LE
authors: de-Bashan
authors: 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.
authors: Juan-Pablo
authors: JP
authors: Hernandez
authors: 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, 209 Life Sciences Building, Auburn Univ., Auburn, AL 36849, USA. Electronic address: ybb0001@auburn.edu.
authors: Yoav
authors: Y
authors: Bashan
mesh_terms: D000464:Alginates / Q000378:metabolism; D015806:Azospirillum brasilense / Q000235:genetics / Q000378:metabolism*; D018914:Cells, Immobilized; D048408:Chlorella vulgaris / Q000187:drug effects / Q000378:metabolism*; D003470:Culture Media; D003593:Cytoplasm / Q000378:metabolism*; D005816:Genetic Complementation Test; D020723:Glucuronic Acid / Q000378:metabolism; D006603:Hexuronic Acids / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism* / Q000494:pharmacology; D009154:Mutation; D011122:Polyphosphates / Q000378:metabolism*
chemical_list: D000464:Alginates; D003470:Culture Media; D006603:Hexuronic Acids; D007210:Indoleacetic Acids; D011122:Polyphosphates; C030737:indoleacetic acid; D020723:Glucuronic Acid
keywords: Azospirillum; Chlorella; Indole-3-acetic acid; Phosphorus uptake; Plant growth-promoting bacteria; Polyphosphate