The 'squalene route' to carotenoid biosynthesis is widespread in Bacteria.

2021 ◽  
Author(s):  
Carlos Santana-Molina ◽  
Valentina Henriques ◽  
Damaso Hornero-Méndez ◽  
Damien P. Devos ◽  
Elena Rivas-Marin
Keyword(s):  
Biosynthetic Pathway ◽  
Carotenoid Biosynthesis ◽  
Stress Conditions ◽  
Widespread Occurrence ◽  
Functional Roles ◽  
Evolutionary Scenario ◽  
Carotenoid Biosynthetic Pathway ◽  
Potential Origin

Squalene is mostly associated with the biosynthesis of polycyclic triterpenes. Although there have been suggestions that squalene could be involved in the biosynthesis of carotenoids, functionally and evolutionarily related to polycyclic triterpenes, evidence of this 'squalene route' in nature was lacking. We demonstrate that planctomycetes synthesize C30 carotenoids via squalene and that this 'squalene route' is widely distributed in Bacteria. We also investigated the functional roles of hopanoids and carotenoids in Planctomycetes and show that their protective functions under stress conditions are complementary. Our evolutionary analyses suggest that the C30 carotenoid biosynthetic pathway is the most ancestral, with a potential origin in Firmicutes or Planctomycetes . In addition, we propose an evolutionary scenario to explain the diversification of the different carotenoid and squalene pathways. Together, these results improve the evolutionary contextualization of these molecules. Likewise, the widespread occurrence of the squalene route in bacteria increases the functional repertoire of squalene.

scholarly journals A Tetratricopeptide Repeat Protein Regulates Carotenoid Biosynthesis and Chromoplast Development in Monkeyflowers (Mimulus)

2017 ◽  
Author(s):  
Lauren E. Stanley ◽  
Baoqing Ding ◽  
Wei Sun ◽  
Fengjuan Mou ◽  
Connor Hill ◽  
...  
Keyword(s):  
Biosynthetic Pathway ◽  
Anthocyanin Biosynthesis ◽  
Carotenoid Biosynthesis ◽  
Chemical Mutagenesis ◽  
Developmental Genetics ◽  
Tetratricopeptide Repeat ◽  
Loss Of Function ◽  
In Planta ◽  
Biosynthetic Genes ◽  
Carotenoid Biosynthetic Pathway

ABSTRACTThe incredible diversity of floral color and pattern in nature is largely determined by the transcriptional regulation of anthocyanin and carotenoid biosynthetic genes. While the transcriptional control of anthocyanin biosynthesis is well understood, little is known about the factors regulating the carotenoid biosynthetic pathway in flowers. Here, we characterize the Reduced Carotenoid Pigmentation 2 (RCP2) locus from two monkeyflower (Mimulus) species, the bumblebee-pollinated M. lewisii and hummingbird-pollinated M. verbenaceus. We show that loss-of-function mutations of RCP2 cause drastic down-regulation of the entire carotenoid biosynthetic pathway in these species. Through bulk segregant analysis and transgenic experiments, we have identified the causal gene underlying RCP2, encoding a tetratricopeptide repeat (TPR) protein that is closely related to the Arabidopsis Reduced Chloroplast Coverage (REC) proteins. RCP2 appears to regulate carotenoid biosynthesis independently of RCP1, a previously identified R2R3-MYB master regulator of carotenoid biosynthesis. We show that RCP2 is required for chromoplast development and suggest that it most likely regulates the expression of carotenoid biosynthetic genes through chromoplast-to-nucleus retrograde signaling. Furthermore, we demonstrate that M. verbenaceus is just as amenable to chemical mutagenesis and in planta transformation as the more extensively studied M. lewisii, making these two species an excellent platform for comparative developmental genetics studies of two closely related species with dramatic phenotypic divergence.

scholarly journals Chemical inhibition of lycopene β-cyclases unmask operation of phytoene synthase 2 in ripening tomato fruits

2021 ◽  
Author(s):  
Prateek Gupta ◽  
Marta Rodriguez-Franco ◽  
Reddaiah Bodanapu ◽  
Yellamaraju Sreelakshmi ◽  
Rameshwar Sharma
Keyword(s):  
Biosynthetic Pathway ◽  
Carotenoid Biosynthesis ◽  
Phytoene Synthase ◽  
Triethylamine Hydrochloride ◽  
Knockout Mutant ◽  
Tomato Fruits ◽  
Chemical Inhibition ◽  
Specific Pathway ◽  
Carotenoid Biosynthetic Pathway

In ripening tomato fruits, the leaf-specific carotenoids biosynthesis mediated by phytoene synthase 2 (PSY2) is replaced by a fruit-specific pathway by the expression of two chromoplast-specific genes: phytoene synthase 1 (PSY1) and lycopene-β-cyclase (CYCB). Consequently, mutations in those two and other genes contributing to intermediate steps render the ripened tomato fruits bereft of lycopene. To decipher whether PSY2-mediated pathway also operates in ripening fruits, we blocked the in vivo activity of lycopene-β-cyclases by injecting CPTA (2-(4-Chlorophenylthio) triethylamine hydrochloride), an inhibitor of lycopene-β-cyclases. The injection of CPTA induced accumulation of lycopene in leaves, immature-green and ripening fruits. Even, in tomato mutants deficient in fruit-specific carotenoid biosynthesis such as V7 and r (PSY1), and ζ-carotene isomerase (ZISO), CPTA triggered lycopene accumulation. The CPTA-treated ziso mutant fruits, where PSY1 remains functional, accumulated phytoene and phytofluene. Conversely, CPTA-treated PSY1-knockout mutant (r3756) fruits did not accumulate phytoene and phytofluene. CPTA-treated fruits were enriched in lycopene-derived volatiles and had reduced ABA levels. The lycopene accumulation was associated with the partial transformation of chloroplasts to chromoplasts bearing thread-like crystalline structures, indicating lycopene accumulation. Our study shows that inhibition of lycopene β-cyclases unmasks the operation of a parallel carotenoid biosynthetic pathway mediated by PSY2 in ripening tomato fruits.

scholarly journals Genetic Characterization of the Carotenoid Biosynthetic Pathway in Methylobacterium extorquens AM1 and Isolation of a Colorless Mutant

2003 ◽  
Vol 69 (12) ◽  
pp. 7563-7566 ◽  
Author(s):  
Stephen J. Van Dien ◽  
Christopher J. Marx ◽  
Brooke N. O'Brien ◽  
Mary E. Lidstrom
Keyword(s):  
Biosynthetic Pathway ◽  
Genetic Characterization ◽  
Carotenoid Biosynthesis ◽  
Biosynthesis Pathway ◽  
Wild Type ◽  
Methylobacterium Extorquens ◽  
Growth Properties ◽  
Carotenoid Biosynthesis Pathway ◽  
Free Strain

ABSTRACT Genomic searches were used to reconstruct the putative carotenoid biosynthesis pathway in the pink-pigmented facultative methylotroph Methylobacterium extorquens AM1. Four genes for putative phytoene desaturases were identified. A colorless mutant was obtained by transposon mutagenesis, and the insertion was shown to be in one of the putative phytoene desaturase genes. Mutations in the other three did not affect color. The tetracycline marker was removed from the original transposon mutant, resulting in a pigment-free strain with wild-type growth properties useful as a tool for future experiments.

scholarly journals Engineering the carotenoid biosynthetic pathway in Rhodothermus marinus for lycopene production

2020 ◽  
Vol 11 ◽  
pp. e00140
Author(s):  
Thordis Kristjansdottir ◽  
Emanuel Y.C. Ron ◽  
Daniel Molins-Delgado ◽  
Olafur H. Fridjonsson ◽  
Charlotta Turner ◽  
...  
Keyword(s):  
Biosynthetic Pathway ◽  
Rhodothermus Marinus ◽  
Lycopene Production ◽  
Carotenoid Biosynthetic Pathway

scholarly journals Enhancement of carotenoid biosynthesis in Phaffia rhodozyma PR106 under stress conditions

2019 ◽  
Vol 83 (12) ◽  
pp. 2375-2385 ◽  
Author(s):  
Jing Zhang ◽  
Qing-Ru Li ◽  
Ming-Hao Zhang ◽  
Ying You ◽  
Yu Wang ◽  
...  
Keyword(s):  
Carotenoid Biosynthesis ◽  
Phaffia Rhodozyma ◽  
Stress Conditions

scholarly journals Pathway Evolution by Horizontal Transfer and Positive Selection Is Accommodated by Relaxed Negative Selection upon Upstream Pathway Genes in Purple Bacterial Carotenoid Biosynthesis

2009 ◽  
Vol 191 (24) ◽  
pp. 7500-7508 ◽  
Author(s):  
Jonathan L. Klassen
Keyword(s):  
Positive Selection ◽  
Horizontal Transfer ◽  
Negative Selection ◽  
Biosynthetic Pathway ◽  
Carotenoid Biosynthesis ◽  
Biochemical Network ◽  
Biosynthetic Genes ◽  
Substrate Specificities ◽  
Functional Changes ◽  
Synonymous Mutations

ABSTRACT Horizontal gene transfer and selection are major forces driving microbial evolution. However, interactions between them are rarely studied. Phylogenetic analyses of purple bacterial carotenoid biosynthesis genes suggest two lineages: one producing spheroidenone and the other producing spirilloxanthin. Of the latter lineage, Rubrivivax gelatinosus S1 and Hoeflea phototrophica DFL-43 also or instead produce spheroidenone. Evolution of the spheroidenone pathway from that producing spirilloxanthin theoretically requires changes in the substrate specificity of upstream pathway enzymes and acquisition of a terminal ketolase (CrtA). In R. gelatinosus and likely also in H. phototrophica, CrtA was acquired from the Bacteroidetes, in which it functions as a hydroxylase. Estimation of nonsynonymous and synonymous mutations using several pairwise methods indicated positive selection upon both genes, consistent with their functional changes from hydroxylases to ketolases. Relaxed negative selection upon all other carotenoid biosynthetic genes in these organisms was also apparent, likely facilitating changes in their substrate specificities. Furthermore, all genes responsible for terminal carotenoid biosynthetic pathway steps were under reduced negative selection compared to those known to govern biosynthetic pathway specificity. Horizontal transfer of crtA into R. gelatinosus and H. phototrophica has therefore likely been promoted by (i) the apparent selective advantage of spheroidenone production relative to spirilloxanthin production, (ii) reduced negative selection upon other carotenoid biosynthetic genes, facilitating changes in their substrate specificities, and (iii) preexisting low enzyme substrate specificities due to relaxed negative selection. These results highlight the importance and complexity of selection acting upon both a horizontally transferred gene and the biochemical network into which it is integrating.

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