Identification of a novel anthocyanin synthesis pathway in the fungus Aspergillus sydowii H-1

Abstract

Background: Anthocyanins are common substances with many agro-food industrial applications. However, anthocyanins are generally considered to be found only in natural plants. Our previous study isolated and purified the fungus Aspergillus sydowii H-1, which can produce purple pigments during fermentation. To understand the characteristics of this strain, a transcriptomic and metabolomic comparative analysis was performed with A. sydowii H-1 from the second and eighth days of fermentation, which confer different pigment production. Results: We found five anthocyanins with remarkably different production in A. sydowii H-1 on the eighth day of fermentation compared to the second day of fermentation. LC-MS/MS combined with other characteristics of anthocyanins suggested that the purple pigment contained anthocyanins. A total of 28 transcripts related to the anthocyanin biosynthesis pathway was identified in A. sydowii H-1, and almost all of the identified genes displayed high correlations with the metabolome. Among them, the chalcone synthase gene (CHS) and cinnamate-4hydroxylase gene (C4H) were only found using the de novo assembly method. Interestingly, the best hits of these two genes belonged to plant species. Finally, we also identified 530 lncRNAs in our datasets, and among them, three lncRNAs targeted the genes related to anthocyanin biosynthesis via cis-regulation, which provided clues for understanding the underlying mechanism of anthocyanin production in fungi. Conclusion: We first reported that anthocyanin can be produced in fungus, A. sydowii H-1. Totally, 31 candidate transcripts were identified involved in anthocyanin biosynthesis, in which CHS and C4H, known as the key genes in anthocyanin biosynthesis, were only found in strain H1, which indicated that these two genes may contribute to anthocyanins producing in H-1. This discovery expanded our knowledges of the biosynthesis of anthocyanins and provided a direction for the production of anthocyanin.

Lignin Nanoparticles: A Promising Tool to Improve Maize Physiological, Biochemical, and Chemical Traits

“…As for anthocyanin, increases were generally observed in maize following the different treatments with LNP. Anthocyanin belongs to the flavonoid family, and they show fundamental properties in plants and therapeutic effects in humans [ 74 ]. Anthocyanin can act on ROS into the vacuole, inhibiting and contrasting the lipid peroxidation, and in general, their content can be increased in response to various environmental stresses [ 75 ].…”

“…In light of the above, maize perceived T80 and T312 as a signal at a non-phytotoxic level, increasing anthocyanin content. Indeed, anthocyanins are synthesized in the phenylpropanoid pathway [ 74 ], and their increase following the exposure to LNP can be explained by the capacity of substances containing phenols to induce the above metabolic pathway [ 64 ]. Moreover, the chlorophyll content can also be linked to anthocyanin increase, being the increase in chlorophyll content a possible physiological response that can compensate for eventual increases in anthocyanin [ 69 ].…”

Serendipita indica changes host sugar and defense status in Arabidopsis thaliana: cooperation or exploitation?

“…In addition, UDP glucose is discussed to be an extracellular signaling molecule, which may even be perceived as damage-associated molecular pattern (Janse van Rensburg and Van den Ende 2017). Sucrose also plays a role in the induction of anthocyanin biosynthesis (Solfanelli et al 2006;Das et al 2012), which was shown in plants colonized by different fungal endophytes (Yu et al 2020;Bu et al 2020), and promotes phenylpropanoid biosynthesis (Ferri et al 2011), which was shown in plants colonized by the endophyte Gilmaniella sp. (Yuan et al 2019).…”

Azolla ferns testify: seed plants and ferns share a common ancestor for leucoanthocyanidin reductase enzymes

“…Synthesis of flavonols for N. azollae that are locked into nitrogen fixation in the leaf cavities, may thus have been taken over by the fern host in the Azolla symbiosis. Some fungi synthesise leucoanthocyanidins, suggesting that these metabolites are not restricted to cyanobacteria and plant lineages (Bu et al ., 2020). A thorough analysis of cyanobacterial FBP enzymes will reveal whether enzymes such as DFR appeared in the plant, fungal and cyanobacterial lineages by convergent evolution or horizontal gene transfer.…”