Use of fatty acids in the chemotaxonomy of the family Selenastraceae (Sphaeropleales, Chlorophyceae)

Author(s)

Mori, Cilene Cristina ^[1] ; Bagatini, Inessa Lacativa ^[1] ; da Silva, Thais Garcia ^[1] ; Parrish, Christopher Charles ^[2] ; Henriques Vieira, Armando Augusto ^[1]

Affiliation

^[1] Univ Fed Sao Carlos, Phycol Lab, Dept Bot, Washington Luis Highway SP 310, 235 Km, BR-13565905 Sao Carlos, SP - Brazil

^[2] Mem Univ Newfoundland, Ocean Sci Ctr, Dept Ocean Sci, Marine Lab Rd, St John, NF A1C 5S7 - Canada

• Document type: Journal article
• Source: Phytochemistry; v. 151, p. 9-16, JUL 2018.
• Web of Science Citations: 1

Abstract

The family Selenastraceae includes many species of freshwater green microalgae with morphological characteristics that are so subtly different that it is difficult to discriminate species within it. Therefore, the use of the diacritical characteristics of traditional morphological taxonomy may be ineffective at differentiating among many species of the family. Chemotaxonomy based on fatty acid methyl ester (FAME) can help resolve uncertainties not completely addressed by other approaches, such as molecular studies of some species within the Selenastraceae. Here, we first tested three techniques for the analysis of microalgal FAME to choose the one that would provide the best profiles for chemotaxonomy: 1) direct transesterification (DT) of the biomass followed by gas chromatography coupled to mass spectrometry analysis (GC-MS); 2) extraction using chloroform and methanol, followed by transesterification (T) and then analysis by gas chromatography/flame ionization detector (GC-FID); and 3) extraction with chloroform and methanol and then separation into lipid classes using thin-layer chromatography (TLC) using the latroscan-Chromarod system. The tests were conducted on 12 strains (11 species) of Selenastraceae and one outgroup strain. The fatty acid profiles produced by the DT-GC-MS technique yielded the best results for the chemotaxonomy of the Selenastraceae species using 12 FAME. The proportion of the variance in the fatty acid profiles obtained with DT-GC-MS analysis explained by species was 85%, whereas the differences explained by strains was 92%. Therefore, DT-GC-MS was used to analyze other microalgae strains, totaling 15 species of 8 genera of green coccoid microalgae, including the recently described Curvastrum. The results with all strains showed that fatty acid profiles obtained by DT-GC-MS were significantly different (p < 0.001) among strains and among species. The variance in fatty acids profiles explained by separation into strains was 97%, whereas the separation into species explained 93% of the variance. Statistical analyses showed that, for our dataset, the C-18 fatty acids 18:3 omega 3 and 18:4 omega 6 were indicative of the Selenastraceae. Therefore, fatty acid profiles are a useful auxiliary chemotaxonomic tool for species identification in Selenastraceae. (C) 2018 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 13/03979-8 - Profile of fatty acids in freshwater microalgae species, family Selenastraceae, Chlorophyta, as chemotaxonomic characteristic and prospecting applicability
• Grantee: Cilene Cristina Mori
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 11/50054-4 - Biodiversity of freshwater microalgae: germplasm bank and obtaining of molecular markers of cryopreserved species
• Grantee: Armando Augusto Henriques Vieira
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants
• FAPESP's process: 12/19520-1 - Biodiversity of Selenastraceae (freshwater Chlorococcaceae microalgae): morphological characteristics and sequencing of 18S rDNA as a traditional taxonomic basis for obtaining the DNA barcode
• Grantee: Thaís Garcia da Silva
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 13/18083-0 - Selenastraceae (Chlorococcales) family: evaluation of molecular marker potencies for DNA barcoding and for phylogeny of the genera Monoraphidium and Ankistrodesmus
• Grantee: Inessa Lacativa Bagatini
• Support Opportunities: Scholarships in Brazil - Post-Doctoral