title: Phosphate deficiency (N/P 40:1) induces mcyD transcription and microcystin synthesis in Microcystis aeruginosa PCC7806.
abstract: A real-time RT-PCR analysis of the transcriptional response to phosphate availability of the mcyD gene and microcystin-LR synthesis in Microcystis aeruginosa PCC7806 revealed that no significant changes were observed in the relative quantification of mcyD under excess phosphate (N/P = 1:1), whereas in deficiency of this nutrient (N/P = 40:1), a steady increase of mcyD during the exponential growth phase was detected, showing a maximal level on the 7th day of growth with a 6.8-fold increase over the control cells. The microcystin content in phosphate deficient cells correlates with the trend of mcyD transcription observed. Also, in this work we demonstrate that under phosphate deficiency conditions with a ratio of 40:1 N/P, the growth of M. aeruginosa PCC7806 was not affected when compared to control and phosphate excess samples. When blooms occur, the nutrients become exhausted and therefore phosphate availability will be scarce. In such a complex scenario, microcystin synthesis could be a response to phosphate deficiency, among other stress parameters.
authors.affiliation: Departamento de Bioquimica y Biologia Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain.
authors.forename: Taís M
authors.initials: TM
authors.lastname: Kuniyoshi
authors.forename: Emma
authors.initials: E
authors.lastname: Sevilla
authors.forename: M Teresa
authors.initials: MT
authors.lastname: Bes
authors.forename: Maria F
authors.initials: MF
authors.lastname: Fillat
authors.forename: M Luisa
authors.initials: ML
authors.lastname: Peleato
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D052998:Microcystins / Q000235:genetics / Q000378:metabolism*; D046931:Microcystis / Q000235:genetics / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D009876:Operon / Q000235:genetics; D010710:Phosphates / Q000172:deficiency* / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D001426:Bacterial Proteins; D052998:Microcystins; D010710:Phosphates; D009584:Nitrogen