on Algae and the evolution of complex life: symbiotic RNA kickback safety mechanism?

 alga called Chlorella that can often be found living inside an aquatic microbe called Paramecium bursaria. The pair trade food and nutrients, but the alga is in a vulnerable spot: Why doesn’t the microbe just digest it? One study suggested that an “RNA brake” system might protect the alga (and the mutually beneficial partnership). If the Paramecium host attacked its algal endosymbiont, free-floating algal RNA would burst out into its cytoplasm, which could set off processes that would ultimately harm the larger microbe. Understanding this mechanism could be key to figuring out the story of how eukaryotes first evolved, likely from an ancient endosymbiotic relationship.