Bridging Place-Based Astrobiology Education with Genomics, Including Descriptions of Three Novel Bacterial Species Isolated from Mars Analog Sites of Cultural Relevance

Democratizing genomic data science, including bioinformatics, can diversify the STEM workforce and may, in turn, bring new perspectives into the space sciences. In this respect, the development of education and research programs that bridge genome science with "place" and world-views specific to a given region are valuable for Indigenous students and educators. Through a multi-institutional collaboration, we developed an ongoing education program and model that includes Illumina and Oxford Nanopore sequencing, free bioinformatic platforms, and teacher training workshops to address our research and education goals through a place-based science education lens. High school students and researchers cultivated, sequenced, assembled, and annotated the genomes of 13 bacteria from Mars analog sites with cultural relevance, 10 of which were novel species. Students, teachers, and community members assisted with the discovery of new, potentially chemolithotrophic bacteria relevant to astrobiology. This joint education-research program also led to the discovery of species from Mars analog sites capable of producing N-acyl homoserine lactones, which are quorum-sensing molecules used in bacterial communication. Whole genome sequencing was completed in high school classrooms, and connected students to funded space research, increased research output, and provided culturally relevant, place-based science education, with participants naming three novel species described here. Students at St. Andrew's School (Honolulu, Hawai'i) proposed the name Bradyrhizobium prioritasuperba for the type strain, BL16AT, of the new species (DSM 112479T = NCTC 14602T). The nonprofit organization Kauluakalana proposed the name Brenneria ulupoensis for the type strain, K61T, of the new species (DSM 116657T = LMG = 33184T), and Hawai'i Baptist Academy students proposed the name Paraflavitalea speifideiaquila for the type strain, BL16ET, of the new species (DSM 112478T = NCTC 14603T).

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Serious outbreaks of walnut deep bark canker were observed on young walnut trees (Juglans regia L.) in two localities in the northern part of Serbia during 2020. From the symptomatic walnut tissues, two types of bacterial colonies were isolated, predominantly, light cream, circular and smooth colonies, as well as small, yellowish, mucoid and convex ones. PCR analysis and phenotypic assays suggested that the former group belongs to Brenneria spp., while the latter isolates were identified as Xanthomonas arboricola pv. juglandis. Within the Brenneria group, two strains were identified as Brenneria nigrifluens, while other 15 strains did not belong to any Brenneria species described so far. Therefore, we selected four representative strains of the unknown Brenneria sp. and subjected them to polyphasic analysis. As expected, in a phylogenetic tree based on partial 16S rDNA sequences, four novel strains grouped with other Brenneria representatives, and showed close phylogenetic relationship to Brenneria salicis. Furthermore, multilocus sequence analysis (MLSA) based on the partial sequences of atpD, gyrB, infB and rpoB housekeeping genes and core-genome phylogeny indicated that the studied strains form a novel and a clearly separate Brenneria lineage. Overall genome relatedness indices showed that they represent a new Brenneria species. The new species can be differentiated from the other Brenneria spp. infecting walnut and closely related B. salicis strains based on phenotypic characteristics, as well. Moreover, the pathogenicity tests on two-year-old walnut plants proved the ability of strains to cause necrosis and longitudinal black lesions and cracks on the trunk and branches of walnut trees. Overall, polyphasic characterization showed that the studied strains isolated from walnut with symptoms of deep bark canker represent a novel species of the genus Brenneria for which the name Brenneria izbisi sp. nov. is proposed. The type strain of B. izbisi is KBI 423^T (= CFBP 9035^T = LMG 32479^T). To facilitate rapid identification of newly described species, a conventional PCR protocol and primers targeting the putative gene hrpP, were developed. Further study should reveal the potential role of each pathogen isolated from symptomatic walnut in disease development as well as possible interaction between them.

nov., isolated from symptomatic Tilia × moltkei and Tilia × europaea trees in the UK

Several strains of a previously undescribed bacterial species were isolated from mature Tilia hybrid trees suffering from bleeding cankers at various geographic locations in the UK. The strains were Gram-negative, facultatively anaerobic, and partial sequencing of the gyrB gene revealed that the strains belong to the genus Brenneria with the closest phylogenetic neighbours being Brenneria corticis and Brenneria nigrifluens. Further investigation using a polyphasic approach was undertaken to determine the taxonomic position of the novel species. Phylogenies based on the 16S rRNA gene and multilocus sequence analysis of partial housekeeping gene sequences of gyrB, rpoB, infB and atpD revealed that the strains formed an independent cluster within the genus Brenneria. The phenotypic and chemotaxonomic assays demonstrated that the strains could be differentiated from the closest relatives. Genome analysis of representative strains revealed in silico DNA-DNA hybridization values below the threshold for species delimitation, although the average nucleotide identity values obtained when compared to B. corticis (95.9-96%) were slightly higher than the suggested cut-off value of 95%. However, as all other data suggests that the strains belong to a novel taxon that can be differentiated from the closest relatives, we propose that the strains represent a novel species in the genus Brenneria, Brenneria tiliae sp. nov. (type strain WC1b.1^T=LMG 32575^T=NCPPB 4697^T).