Comment by adrian_b

While the research about Paulinella is very interesting, it has no relationship whatsoever with "the origins of life".

What this research is about is the origin of plants, which are indeed one of the most important forms of life, but the origin of plants is distant by billions of years from the origin of life and it is even distant by billions of years from the origin of phototrophy (frequently, but not really correctly, called "photosynthesis", i.e. the extraction of energy from solar light).

The ancestor of red algae and green algae (the terrestrial plants are descended from green algae) has been created by the hybridization through symbiosis between a unicellular eukaryote (i.e. nucleated cell) and a cyanobacterium, a.k.a. blue-green alga.

As explained in TFA, Paulinella is the second case of such a symbiosis between a nucleated cell and a cyanobacterium, which happened relatively recently, unlike the symbiosis from the origin of plants, which happened about a billion and a half years ago.

Because Paulinella and its internal symbionts have not been modified so profoundly by symbiosis like the red algae or green algae, it can provide information about how the early stages of the hybridization happened, eventually allowing a better understanding of how plants function.