The green alga Haematococcus lacustris (formerly Haematococcus pluvialis) ) is a primary source of astaxanthin, a ketocarotenoid with high antioxidant activity and several industrial applications. Here, the Haematococcus lacustris highly repetitive genome was reconstructed by exploiting next-generation sequencing integrated with Hi-C scaffolding, obtaining a 151 Mb genome assembly in 32 scaffolds at a near-chromosome level with high continuity. Surprisingly, the distribution of the single-nucleotide-polymorphisms identified demonstrates a diploid configuration for the Haematococcus genome, further validated by Sanger sequencing of heterozygous regions. Functional annotation and RNA-seq data enabled the identification of 13,946 nuclear genes, with >5000 genes not previously identified in this species, providing insights into the molecular basis for metabolic rearrangement in stressing conditions such as high light and/or nitrogen starvation, where astaxanthin biosynthesis is triggered. These data constitute a rich genetic resource for biotechnological manipulation of Haematococcus lacustris highlighting potential targets to improve astaxanthin and carotenoid productivity.

Haematococcus lacustris genome assembly and annotation reveal diploid genetic traits and stress-induced gene expression patterns

Marcolungo, Luca;Bellamoli, Francesco;Cecchin, Michela;Lopatriello, Giulia;Rossato, Marzia;Cosentino, Emanuela;Rombauts, Stephane;Delledonne, Massimo;Ballottari, Matteo
2024-01-01

Abstract

The green alga Haematococcus lacustris (formerly Haematococcus pluvialis) ) is a primary source of astaxanthin, a ketocarotenoid with high antioxidant activity and several industrial applications. Here, the Haematococcus lacustris highly repetitive genome was reconstructed by exploiting next-generation sequencing integrated with Hi-C scaffolding, obtaining a 151 Mb genome assembly in 32 scaffolds at a near-chromosome level with high continuity. Surprisingly, the distribution of the single-nucleotide-polymorphisms identified demonstrates a diploid configuration for the Haematococcus genome, further validated by Sanger sequencing of heterozygous regions. Functional annotation and RNA-seq data enabled the identification of 13,946 nuclear genes, with >5000 genes not previously identified in this species, providing insights into the molecular basis for metabolic rearrangement in stressing conditions such as high light and/or nitrogen starvation, where astaxanthin biosynthesis is triggered. These data constitute a rich genetic resource for biotechnological manipulation of Haematococcus lacustris highlighting potential targets to improve astaxanthin and carotenoid productivity.
2024
Haematococcus
Astaxanthin
Ploidy
Genome assembly
Microalgae
Next-generation sequencing
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11562/1143906
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