Diversity of Frankia strains nodulating HippÖphae salicifolia D. Don using FAME profiling as Chemotaxonomic markers

Two unusual conjugated fatty acids, parinaric acid and α-eleostearic acid, are present in several Impatiens species, but not in congener Hydrocera triflora

Parinaric and α-eleostearic acids are unusual conjugated fatty acids. Unusual fatty acids, in general, are known to have roles in defense response; however, the role of parinaric acid in I. balsamina is not known, nor is it known whether it occurs in different species of Impatiens or its closest monotypic relative, Hydrocera triflora (L.) Wight & Arn. The aim of the study was to (a) characterize the fatty acid composition of 21 species of Impatiens and H. triflora and (b) determine whether parinaric and α-eleostearic acids are present in these taxa and, if so, (c) whether there is interspecific and intraspecific variation in parinaric acid content. Fatty acid profiling was done using gas chromatography and mass spectrometry (GC-MS). To uncover taxonomic patterns of variation in fatty acids, principal component analysis and hierarchical cluster analysis were performed. The major fatty acids in Impatiens were found to be palmitic (5.57-20.85%), stearic (2.86-21.61%), oleic (2.79-28.99%), linoleic (C18:2Δ^9,12, 2.04-26.64%), α-linolenic (C18:3∆^9,12,15; 11.07-53.99%), and four forms of parinaric acid (5.93-70.21%). Genus Impatiens contains two unusual conjugated fatty acids- parinaric and α-eleostearic, however these are absent in closely related H. triflora. This study reports the presence of four different forms of parinaric acid in Impatiens for the first time. Some species (I. mengtszeana, I. racemulosa and I. oppositifolia) were found to contain very high levels (> 50%) of parinaric acid and they might be useful for various biomedical and industrial applications. Apparently, the presence of parinaric acid is a characteristic of Impatiens. Significant variations were found in the amount and forms of parinaric acid. We propose the potential application of parinaric acid and α-eleostearic acid as chemotaxonomic markers for Impatiens.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12298-022-01194-4.

Transcriptional regulation of acetyl CoA and lipid synthesis by PII protein in Synechococcus PCC 7942

P_II protein family is widespread in prokaryotes and plants. In this study, impacts of P_II deficiency on the synthesis of acetyl CoA and acetyl CoA carboxylase enzyme (ACCase) was analyzed in the Synechococcus sp. PCC 7942 by evaluating the mRNA levels of pyruvate kinase (PK), pyruvate dehydrogenase (PDH), citrate synthase (CS), biotin synthase (BS), biotin carboxylase (BC), biotin carboxyl carrier protein (BCCP), carboxyl transferase (CT) α and β subunits. The P_II deficient Synechococcus sp. PCC 7942 showed upregulation of all the above-mentioned genes, except CS. Analyses of genes required for acetyl coA synthesis exhibited a substantial increase in the transcript levels of PK and PDH in the P_II mutant strain. In addition, the P_II mutant also displayed reduced acetyl CoA content, high ACCase activity, and increased lipid content. The lessening of acetyl CoA content was attributed to the rapid utilization of acetyl CoA in fatty acid synthesis as well as in the TCA cycle whereas the increased ACCase activity was ascribed to the rise in mRNA levels of BS, BC, BCCP, CT α, and β genes. However, increased lipid content was correlated with the declined total protein content. Hence, the study suggested that P_II protein regulates the synthesis of acetyl CoA and ACCase enzyme at the transcriptional level.

Fatty acid profiling and multivariate analysis in the genus Leucas reveals its nutritional, pharmaceutical and chemotaxonomic significance

Genus Leucas with about 41 species found in India, is an Asian genus with separation from its close relatives in Africa based on phylogenetic evidence. Present study represents the only comprehensive phytochemical investigation on this genus. We have analyzed the seed fatty acid compositions of 26 species and five varieties of Leucas for nutritional, pharmaceutical and chemotaxonomic perspectives. The fatty acids and their composition in seeds of Leucas species, collected from different geographical regions in India, were analyzed by gas chromatography and mass spectrometry. Significant variations have been observed in fatty acid profiles among species and their varieties. We observed major fatty acids as palmitic, stearic, oleic, linoleic and laballenic acid; whereas myristic, palmitoleic, cis-vaccenic, linolenic, eicosanoic, eicosenoic, phlomic and docosanoic acid were detected in minor quantities. Laballenic and phlomic acids are unusual allenic fatty acids found in few Lamiaceae members from order Lamiales. Laballenic acid, a proven molecule of pharmaceutical importance, was observed in all the Leucas species studied. Three species of Leucas; L. helianthimifolia, L. ciliata var. vestita and L. hirta were found to contain ≥40% laballenic acid and can act as potential source for isolation of pharmaceutical compounds. This study also reports the presence of another allenic fatty acid, phlomic acid, in several Leucas species. Principal component analysis and hierarchical cluster analysis showed a distinct separation among the species based on abundance of similar fatty acids. The fatty acid profile appears to be overlapping at higher level and does not support separation of Asian Leucas from its African relatives and the inclusion of Asian taxa in morphologic sections. However, hierarchical clustering of L. helianthimifolia, L. ciliata var. vestita and L. hirta supported treatment under the morphologic section Astrodon. Multivariate analysis on the chemometric data also supported this cluster as the most prominent source of medicinally useful laballenic acid. Based on the FAs profile, a reconsideration of species boundaries in L. ciliata and L. marrubioides species complex is proposed.

Fatty acid profiling of tropical marine macroalgae: an analysis from chemotaxonomic and nutritional perspectives

The lipid and fatty acid (FA) compositions for 100 marine macroalgae were determined and discussed from the context of chemotaxonomic and nutritional perspectives. In general, the lipid contents in macroalgae were low (2.3-20 mg/g fr. wt.) but with substantially high amounts of nutritionally important polyunsaturated fatty acids (PUFAs) such as LA, ALA, STA, AA, EPA and DHA, that ranged from 10% to 70% of TFAs. More than 90% of the species showed nutritionally beneficial n6/n3 ratio (0.1:1-3.6:1) (p≤0.001). A closer look at the FA data revealed characteristic chemotaxonomic features with C18 PUFAs (LA, ALA and STA) being higher in Chlorophyta, C20 PUFAs (AA and EPA) in Rhodophyta while Phaeophyta depicted evenly distribution of C18 and C20 PUFAs. The ability of macroalgae to produce long-chain PUFAs could be attributed to the coupling of chloroplastic FA desaturase enzyme system from a photosynthetic endosymbiont to the FA desaturase/elongase enzyme system of a non-photosynthetic eukaryotic protist host. Further, the principal component analysis segregated the three macroalgal groups with a marked distinction of different genera, families and orders, Hierarchical cluster analyses substantiated the phylogenetic relationships of all orders investigated except for those red algal taxa belonging to Gigartinales, Ceramiales, Halymeniales and Rhodymeniales for which increased sampling effort is required to infer a conclusion. Also, the groups deduced from FA compositions were congruent with the clades inferred from nuclear and plastid genome sequences. This study further indicates that FA signatures could be employed as a valid chemotaxonomic tool to differentiate macroalgae at higher taxonomic levels such as family and orders.