Comparative Genomics Discloses the Uniqueness and the Biosynthetic Potential of the Marine Cyanobacterium Hyella patelloides

Abstract

Baeocytous cyanobacteria (Pleurocapsales/Subsection II) can thrive in a wide range of habitats on Earth but, compared to other cyanobacterial lineages, they remain poorly studied at genomic level. In this study, we sequenced the first genome from a member of the Hyella genus-H. patelloides LEGE 07179, a recently described species isolated from the Portuguese foreshore. This genome is the largest of the thirteen baeocyteforming cyanobacterial genomes sequenced so far, and diverges from the most closely related strains. Comparative analysis revealed strain-specific genes and horizontal gene transfer events between H. patelloides and its closest relatives. Moreover, H. patelloides genome is distinctive by the number and diversity of natural product biosynthetic gene clusters (BGCs). The majority of these clusters are strain-specific BGCs with a high probability of synthesizing novel natural products. One BGC was identified as being putatively involved in the production of terminal olefin. Our results showed that, H. patelloides produces hydrocarbon with C 15 chain length, and synthesizes C 14 , C 16 , and C 18 fatty acids exceeding 4% of the dry cell weight. Overall, our data contributed to increase the information on baeocytous cyanobacteria, and shed light on H. patelloides evolution, phylogeny and natural product biosynthetic potential.

Final Destination? Pinpointing Hyella disjuncta sp. nov. PCC 6712 (Cyanobacteria) Based on Taxonomic Aspects, Multicellularity, Nitrogen Fixation and Biosynthetic Gene Clusters

“…The genome of H. disjuncta PCC 6712 was sequenced and published by Shih et al 2013 [ 15 ] and a comparison with H. patelloides LEGE 07179 (as reference genome) was performed by Brito et al 2020 [ 14 ]. Here, we have expanded the genomic analysis of H. disjuncta PCC 6712 to include genes involved in multicellularity, nitrogen fixation, the presence of encoded BGCs (AntiSMASH) and potential antibiotic resistance mechanisms (ARTS 2.0).…”

“…Comparison of the H. disjuncta PCC 6712 within the AntiSMASH framework was used to identify BGCs that may be present in other cyanobacterial genomes or are likely to be species/strain specific. Interestingly, none of the cryptic BGCs were present in H. patelloides LEGE 07179 as a result of the AntiSMASH search, although Brito et al 2020 [ 14 ] found similarities in gene cluster families between the two organisms when using BiG-SCAPE analysis with a 0.7 cut-off which included a single terpene BGC (Region 3.11) and the NRPS-like gene cluster corresponding to the known 1-heptadecene pathway (Region 3.9).…”

“…Their early findings were based on the species H. caespitosa; its complex life cycle and morphology is described in depth by Le Campion-Alsumand and Golubić 1985 [ 61 ], ranging from unicellular single celled-stadia, baeocyte formation and H-shaped gelatinous cushion formation between cells up to complex branching patterns of well-expressed pseudofilaments. Comparable morphological characteristics were also described for H. balani [ 61 ] and H. patelloides LEGE 07179 [ 14 ]. Besides well-documented morphological comparisons, only a few isolates made their way into public culture collections, allowing a thorough analysis of their taxonomy corroborated by modern phylogenetic tools such as 16S rRNA or whole genome sequencing.…”

“…The isolate ‘ Chroococcidiopsis sp.’ PCC 6712 was also a major focus with respect to novel natural products [ 14 ] enabled by the release of the full genome by [ 15 ]. Brito et al [ 14 ] showed a direct phylogenetic relation between ‘ Chroococcidiopsis sp.’ PCC 6712 and Hyella patelloides LEGE 07179 on a genome level, and a previous study by Brito et al, in 2017 [ 16 ], also indicated that the strain is Pleurocapsalean based on 16S phylogeny and might be an additional species of the genus Hyella .…”

“…The isolate ‘ Chroococcidiopsis sp.’ PCC 6712 was also a major focus with respect to novel natural products [ 14 ] enabled by the release of the full genome by [ 15 ]. Brito et al [ 14 ] showed a direct phylogenetic relation between ‘ Chroococcidiopsis sp.’ PCC 6712 and Hyella patelloides LEGE 07179 on a genome level, and a previous study by Brito et al, in 2017 [ 16 ], also indicated that the strain is Pleurocapsalean based on 16S phylogeny and might be an additional species of the genus Hyella . Interestingly, a discrepancy appeared behind this idea because a main feature of the genus Hyella is the prominent formation of pseudofilaments, a characteristic that is well present in H. patelloides LEGE 07179 but was not described previously for strain PCC 6712 [ 6 , 7 , 17 , 18 , 19 ].…”