Genome evolution of a non-parasitic secondary heterotroph, the diatom Nitzschia putrida [article]

Ryoma Kamikawa, Takako Mochizuki, Mika Sakamoto, Yasuhiro Tanizawa, Takuro Nakayama, Ryo Onuma, Ugo Cenci, Daniel Moog, Samuel Speak, Krisztina Sarkozi, Andrew Toseland, Cock van Oosterhout (+17 others)
2021 bioRxiv   pre-print
Secondary loss of photosynthesis is observed across almost all plastid-bearing branches of the eukaryotic tree of life. However, genome-based insights into the transition from a phototroph into a secondary heterotroph have so far only been revealed for parasitic species. Free-living organisms can yield unique insights into the evolutionary consequence of the loss of photosynthesis, as the parasitic lifestyle requires specific adaptations to host environments. Here we report on the diploid
more » ... of the free-living diatom Nitzschia putrida (35 Mbp), a non-photosynthetic osmotroph whose photosynthetic relatives contribute ca. 40% of net oceanic primary production. Comparative analyses with photosynthetic diatoms revealed that a combination of genes loss, the horizontal acquisition of genes involved in organic carbon degradation, a unique secretome and the rapid divergence of conserved gene families involved in cell wall and extracellular metabolism appear to have facilitated the lifestyle of a non-parasitic, free-living secondary heterotroph.
doi:10.1101/2021.01.24.427197 fatcat:7ql2sqkpdrhldmdra5okdq4oli