title: High-throughput metabolic screening of microalgae genetic variation in response to nutrient limitation.
abstract: Microalgae produce metabolites that could be useful for applications in food, biofuel or fine chemical production. The identification and development of suitable strains require analytical methods that are accurate and allow rapid screening of strains or cultivation conditions. We demonstrate the use of Fourier transform infrared (FT-IR) spectroscopy to screen mutant strains ofChlamydomonas reinhardtii. These mutants have knockdowns for one or more nutrient starvation response genes, namelyPSR1,SNRK2.1andSNRK2.2. Limitation of nutrients including nitrogen and phosphorus can induce metabolic changes in microalgae, including the accumulation of glycerolipids and starch. By performing multivariate statistical analysis of FT-IR spectra, metabolic variation between different nutrient limitation and non-stressed conditions could be differentiated. A number of mutant strains with similar genetic backgrounds could be distinguished from wild type when grown under specific nutrient limited and replete conditions, demonstrating the sensitivity of FT-IR spectroscopy to detect specific genetic traits. Changes in lipid and carbohydrate between strains and specific nutrient stress treatments were validated by other analytical methods, including liquid chromatography-mass spectrometry for lipidomics. These results demonstrate that thePSR1gene is an important determinant of lipid and starch accumulation in response to phosphorus starvation but not nitrogen starvation. However, theSNRK2.1andSNRK2.2genes are not as important for determining the metabolic response to either nutrient stress. We conclude that FT-IR spectroscopy and chemometric approaches provide a robust method for microalgae screening.
authors.affiliation: Faculty of Life Sciences, The University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT UK.
authors.forename: Amit K
authors.initials: AK
authors.lastname: Bajhaiya
authors.affiliation: Faculty of Life Sciences, The University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT UK.|Department of Geography, University of Sheffield, Sheffield, S10 2TN UK.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Dean
authors.affiliation: Faculty of Life Sciences, The University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Driver
authors.affiliation: School of Chemistry, Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN UK.
authors.forename: Drupad K
authors.initials: DK
authors.lastname: Trivedi
authors.affiliation: School of Chemistry, Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN UK.
authors.forename: Nicholas J W
authors.initials: NJW
authors.lastname: Rattray
authors.affiliation: School of Chemistry, Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN UK.|Environmental & Biochemical Sciences Group, The James Hutton Institute, Invergowrie, Dundee, DD2 5DA Scotland, UK.
authors.forename: J William
authors.initials: JW
authors.lastname: Allwood
authors.affiliation: School of Chemistry, Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN UK.
authors.forename: Royston
authors.initials: R
authors.lastname: Goodacre
authors.affiliation: Faculty of Life Sciences, The University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT UK.
authors.forename: Jon K
authors.initials: JK
authors.lastname: Pittman
keywords: Chlamydomonas reinhardtii; FT-IR spectroscopy; Lipids; Metabolite screening; Microalgae; Starch