Plastid role in phytomelanin synthesis in Piptocarpha axillaris (Less.) Baker stems (Asteraceae, Vernonieae)

Coutinho, Josiane Wolff; Rodrigues, Ana Cláudia; Appezzato‐da‐Glória, Beatriz; Oliveira, Eliana M.; Oliveira, Fernanda Maria Cordeiro de; Lusa, Makeli Garibotti

doi:10.1007/s00709-021-01615-3

Cited by 7 publications

(5 citation statements)

References 31 publications

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“…The assumption is supported by observation of plastid fusion involved into melanin synthesis with vacuoles in Piptocarpha axillaris (Less.) [43]. This allowed us to conclude that in plant tissues, melanin synthesis takes place in plastids and could be accumulated in both the plastids and vacuoles.…”

Section: Discussionmentioning

confidence: 82%

Effects of Combining the Genes Controlling Anthocyanin and Melanin Synthesis in the Barley Grain on Pigment Accumulation and Plant Development

et al. 2022

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Anthocyanins and melanins are phenolic pigments of plants and accumulate in seed envelopes of the barley grain, thereby giving them a blue, purple, or black color. To explore the effects of combined accumulation of anthocyanins and melanins in the grain, a barley near-isogenic line (NIL), characterized by simultaneous accumulation in both pigments, was developed using a marker-assisted approach. The presence of both pigments in the grain pericarp was evaluated by light microscopy. Emergence of anthocyanin pigmentation proved to be temporally separated from that of melanin, and the formation of anthocyanin pigments began at an earlier stage of spike maturation. During spike maturation, a significantly higher total anthocyanin content was noted in the created NIL than in the parental anthocyanin-accumulating NIL, indicating a positive influence of the Blp1 gene on the anthocyanin content at some developmental stages. In a comparative analysis of yield components, it was found that the observed differences between the barley NILs are possibly caused by environmental factors, and the presence of pigments does not decrease plant productivity. Our results should facilitate investigation into genetic mechanisms underlying overlaps in the biosynthesis of pigments and into breeding strategies aimed at the enrichment of barley varieties with polyphenols.

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Section: Discussionmentioning

confidence: 82%

Effects of Combining the Genes Controlling Anthocyanin and Melanin Synthesis in the Barley Grain on Pigment Accumulation and Plant Development

et al. 2022

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“…showed that melanin formation in barley occurred in chloroplast‐derived plastids (Shoeva et al ., 2020 ). Similar report in Piptocarpha axillaris also supported the role of plastid in phytomelanin synthesis (Coutinho et al ., 2021 ). However, in contrast to barley, melanins in Asparagales and Asteraceae plants have been known to be secreted to the extra‐cellular space where they forms a distinct phytomelanin layer (Coutinho et al ., 2021 ).…”

Section: Discussionmentioning

confidence: 99%

“…Similar report in Piptocarpha axillaris also supported the role of plastid in phytomelanin synthesis (Coutinho et al ., 2021 ). However, in contrast to barley, melanins in Asparagales and Asteraceae plants have been known to be secreted to the extra‐cellular space where they forms a distinct phytomelanin layer (Coutinho et al ., 2021 ). The unique accumulation of melanin synthesis in the chloroplast in barley seems to be consistent with the subcellular location of PPO which has been suggested as a chloroplast protein (Glagoleva et al ., 2020 ).…”

Section: Discussionmentioning

confidence: 99%

Transcriptional convergence after repeated duplication of an amino acid transporter gene leads to the independent emergence of the black husk/pericarp trait in barley and rice

Li,

Jia,

et al. 2023

Plant Biotechnology Journal

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SummaryThe repeated emergence of the same trait (convergent evolution) in distinct species is an interesting phenomenon and manifests visibly the power of natural selection. The underlying genetic mechanisms have important implications to understand how the genome evolves under environmental challenges. In cereal crops, both rice and barley can develop black‐coloured husk/pericarp due to melanin accumulation. However, it is unclear if this trait shares a common origin. Here, we fine‐mapped the barley HvBlp gene controlling the black husk/pericarp trait and confirmed its function by gene silencing. The result was further supported by a yellow husk/pericarp mutant with deletion of the HvBlp gene, derived from gamma ray radiation of the wild‐type W1. HvBlp encodes a putative tyrosine transporter homologous to the black husk gene OsBh4 in rice. Surprisingly, synteny and phylogenetic analyses showed that HvBlp and OsBh4 belonged to different lineages resulted from dispersed and tandem duplications, respectively, suggesting that the black husk/pericarp trait has emerged independently. The dispersed duplication (dated at 21.23 MYA) yielding HvBlp occurred exclusively in the common ancestor of Triticeae. HvBlp and OsBh4 displayed converged transcription in husk/pericarp tissues, contributing to the black husk/pericarp trait. Further transcriptome and metabolome data identified critical candidate genes and metabolites related to melanin production in barley. Taken together, our study described a compelling case of convergent evolution resulted from transcriptional convergence after repeated gene duplication, providing valuable genetic insights into phenotypic evolution. The identification of the black husk/pericarp genes in barley also has great potential in breeding for stress‐resilient varieties with higher nutritional values.

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“…This fact may also be of a crucial importance for astrobiology. Also because of similar roles postulated for the so-called phytomelanins, substances of polyphenolic character produced in some groups of higher plants loosely related to animals and fungi (159,160).…”

Section: Melanin Pigment Can Attenuate Chemo-and Radiotherapymentioning

confidence: 96%

Melanoma, Melanin, and Melanogenesis: The Yin and Yang Relationship

et al. 2022

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Melanin pigment plays a critical role in the protection against the harmful effects of ultraviolet radiation and other environmental stressors. It is produced by the enzymatic transformation of L-tyrosine to dopaquinone and subsequent chemical and biochemical reactions resulting in the formation of various 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and 5,6-dihydroxyindole (DHI) oligomers—main constituents of eumelanin, and benzothiazine and benzothiazole units of pheomelanin. The biosynthesis of melanin is regulated by sun exposure and by many hormonal factors at the tissue, cellular, and subcellular levels. While the presence of melanin protects against the development of skin cancers including cutaneous melanoma, its presence may be necessary for the malignant transformation of melanocytes. This shows a complex role of melanogenesis in melanoma development defined by chemical properties of melanin and the nature of generating pathways such as eu- and pheomelanogenesis. While eumelanin is believed to provide radioprotection and photoprotection by acting as an efficient antioxidant and sunscreen, pheomelanin, being less photostable, can generate mutagenic environment after exposure to the short-wavelength UVR. Melanogenesis by itself and its highly reactive intermediates show cytotoxic, genotoxic, and mutagenic activities, and it can stimulate glycolysis and hypoxia-inducible factor 1-alpha (HIF-1α) activation, which, combined with their immunosuppressive effects, can lead to melanoma progression and resistance to immunotherapy. On the other hand, melanogenesis-related proteins can be a target for immunotherapy. Interestingly, clinicopathological analyses on advanced melanomas have shown a negative correlation between tumor pigmentation and diseases outcome as defined by overall survival and disease-free time. This indicates a “Yin and Yang” role for melanin and active melanogenesis in melanoma development, progression, and therapy. Furthermore, based on the clinical, experimental data and diverse effects of melanogenesis, we propose that inhibition of melanogenesis in advanced melanotic melanoma represents a realistic adjuvant strategy to enhance immuno-, radio-, and chemotherapy.

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Plastid role in phytomelanin synthesis in Piptocarpha axillaris (Less.) Baker stems (Asteraceae, Vernonieae)

Cited by 7 publications

References 31 publications

Effects of Combining the Genes Controlling Anthocyanin and Melanin Synthesis in the Barley Grain on Pigment Accumulation and Plant Development

Effects of Combining the Genes Controlling Anthocyanin and Melanin Synthesis in the Barley Grain on Pigment Accumulation and Plant Development

Transcriptional convergence after repeated duplication of an amino acid transporter gene leads to the independent emergence of the black husk/pericarp trait in barley and rice

Melanoma, Melanin, and Melanogenesis: The Yin and Yang Relationship

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