Biology subjects

Capovilla, G.

Publications and source records attributed to Capovilla, G..

4 recordsLinked to original sources

bioRxiv2025

Transformation of plasmid DNA into Prochlorococcus via electroporation

Prochlorococcus is the most numerically abundant photosynthetic organism in the oceans and plays a role in global carbon cycling. Despite its ecological significance and the availability of over a thousand assembled genomes, progress in understanding gene function has been limited by the lack of genetic tools. Here, we report a reproducible electroporation-based protocol to introduce replicative plasmids into two strains of Prochlorococcus representing different ecotypes: MIT9313 (low-light adapted) and MED4 (high-light adapted). Using plasmids carrying a spectinomycin resistance cassette, we achieved transformation in ~33% of MED4 and ~10% of MIT9313 attempts, with greatest success when electroporating cells in late exponential phase. Transformed cells stably retained plasmids and expressed resistance genes, demonstrating functional uptake and gene expression. We also delivered a modified 13 kb plasmid carrying a CRISPR-Cpf1 system into MED4. While no targeted edits were observed, cpf1 and specR were expressed, indicating successful delivery of large constructs and active transcription. These findings represent a key step toward genetic manipulation of Prochlorococcus, enabling future optimization of gene editing approaches and deeper functional analysis of its vast and largely uncharacterized pangenome.

molecular biology↗

bioRxiv2023

Chitin degradation by Synechococcus WH7803

Chitin is an abundant, carbon-rich polymer in the marine environment. Chitinase activity has been detected in spent media of Synechococcus WH7803 cultures - yet it was unclear which specific enzymes were involved. Here we delivered a CRISPR tool into the cells via electroporation to generate loss-of-function mutants of putative candidates and identified ChiA as the enzyme required for the activity detected in the wild type.

microbiology↗

bioRxiv2022

Chitin utilization by marine picocyanobacteria and the evolution of a planktonic lifestyle

Marine picocyanobacteria (Prochlorococcus and Synechococcus), the most abundant photosynthetic cells in the oceans, are generally thought to have a primarily single-celled and free-living lifestyle. However, we find that genes for breaking down chitin - an abundant source of organic carbon that primarily exists as particles - are widespread in this group. We further show that cells with a chitin degradation pathway display chitin degradation activity, attach to chitin particles and show enhanced growth under low light conditions when exposed to chitosan, a partially deacetylated form of chitin. Marine chitin is largely derived from arthropods, whose roots lie in the early Phanerozoic, 520-535 million years ago, close to when marine picocyanobacteria began colonizing the ocean. We postulate that attachment to chitin particles allowed benthic cyanobacteria to emulate their mat-based lifestyle in the water column, initiating their expansion into the open ocean, seeding the rise of modern marine ecosystems. Transitioning to a constitutive planktonic life without chitin associations along a major early branch within the Prochlorococcus tree led to cellular and genomic streamlining. Our work highlights how coevolution across trophic levels creates metabolic opportunities and drives biospheric expansions.

ecology↗

bioRxiv2017

A rainfall-manipulation experiment with 517 Arabidopsis thaliana accessions

The gold standard for studying natural selection and adaptation in the wild is to quantify lifetime fitness of individuals from natural populations that have been grown together in a common garden, or that have been reciprocally transplanted. By combining fitness values with species traits and genome sequences, one can infer selection coefficients at the genetic level. Here we present a rainfall-manipulation experiment with 517 whole-genome sequenced natural accessions of the plant Arabidopsis thaliana spanning the global distribution of the species. The experiments were conducted in two field stations in contrasting climates, in the Mediterranean and in Central Europe, where we built rainout shelters and simulated high and low rainfall. Using custom image analysis we quantified fitness- and phenology-related traits for 23,154 pots, which contained about 14,500 plants growing independently, and over 310,000 plants growing in small populations (max. 30 plants). This large field experiment dataset, which associates fitness and ecologically-relevant traits with genomes, will provide an important resource to test eco-evolutionary genetic theories and to understand the potential evolutionary impacts of future climates on an important plant model species.

evolutionary biology↗