Periodic Reporting for period 1 - D3NAs (Coping with Inhospitable Sweetness: Insights from a (Diversity)^3 Study of Nectar Acinetobacters)
Berichtszeitraum: 2017-08-01 bis 2019-07-31
The overall objective of this Marie Skłodowska-Curie Action (MSCA) was to provide novel insights on why the acinetobacters can thrive so well in floral nectar and animal pollinators. To this end, we followed a multidisciplinary approach that dealt with different levels of study of the diversity of the nectar acinetobacters (“D3 approach”), namely phylogenetic, phenotypic and genomic diversity. Notably, our research approach combined several disciplines, including microbial ecology, population phylogenetics, bacterial physiology, phenomics and genomics, so as to provide the experienced researcher (ER) with numerous opportunities to extend his knowledge in such disciplines, and to establish strong international and multidisciplinary collaborations with several scientists from both the host institution and other organizations. Additionally, through the implementation of this action, the ER aimed to boost his potential for reaching a position of professional maturity by getting additional training in management, communication, dissemination and exploitation of results, and networking.
The activities performed during the implementation of this MSCA were organized into three experimental work packages, one per study level of the diversity of the nectar acinetobacters:
1) Phylogenetic diversity: development of a multilocus sequence analysis scheme for phylogenetic analysis of the nectar acinetobacters.
A collection of 82 strains obtained from floral nectar and insects in different countries (Spain, Belgium, USA and Japan) was successfully typed by a three-loci scheme comprised by the 16S rRNA gene and two different regions (zone 1 and zone 2) of the rpoB gene, which encodes the beta subunit of RNA polymerase. Detailed phylogenetic analysis of the nucleotide sequences revealed the presence of some clades that may represent new species within the genus Acinetobacter.
2) Phenotypic level: high-throughput screening of phenotypic characteristics of the nectar acinetobacters (Fig. 1).
This work package involved the developed of a 96-well plate assays based on Biolog’s phenotype microarray technology to test for assimilation of carbon and nitrogen compounds (30 and 24 assays, respectively), and tolerance to different stressors commonly found in floral nectar (28 assays). Analysis of the phenotypic data obtained for the collection of 82 nectar- and insect-associated acinetobacters by such technology identified seven different profiles for carbon assimilation, 32 different profiles for nitrogen assimilation and ten different profiles for tolerance to inhibitors. Surprisingly, even when they are frequently encountered in floral nectars of high sugar concentration, tested strains could only resist moderate osmotic pressures. Moreover, clustering of strains according to their nitrogen assimilation patterns (but not to their carbon assimilation and tolerance profiles) was linked to species identity. Such clade-driven distribution suggests niche partitioning for assimilation nitrogen resources that may allow coexistence in floral nectar and other habitats.
3) Genomic diversity: whole genome sequencing and analysis of select strains.
This work package was carried out in close collaboration with other research groups that were contacted during the implementation of this MSCA. A set of 11 Acinetobacter strains belonging to different rpoB clades and phenotype clusters were sequenced, and the results confirmed the existence of new species of nectar- and insect-associated acinetobacters among the studied strains.
Non-scientific management activities
Apart from the leading role of the ER in the scientific aspects of the project (experimental work, data analysis and manuscript drafting), he was actively involved in the management aspects of the MSCA, including financial aspects, grant writing and fundraising, networking, and teaching and mentoring of bachelor and master students.
Exploitation and dissemination of results
The results obtained in this MSCA have been disseminated through the participation of the ER in different conferences, the production of some publications for peer-reviewed journals (one published paper and three manuscripts in preparation), and other outreach activities. Moreover, all relevant output coming from this MSCA (publications, pictures, useful links, etc.) has been disseminated through the website and Twitter accounts of the host lab and ER.
Regarding the impact of this MSCA to the host lab, it certainly reinforced its leading position in nectar microbiology research, and opened new avenues for future collaboration in the field. Furthermore, the ER contributed to develop new protocols and analysis methods that are now incorporated in the routine of the host lab. At the same time, the technical and management skills acquired by the ER from the host lab during the implementation of this MSCA have greatly improved his career perspectives.