At the end of the day, there are tons of organisms, many of which can survive epic conditions. My personal favourite is still Deinococcus radiodurans but there are many other contenders.

This here is odd because it seems to follow a "life must be everywhere". I never understood this. Aka NASA wants to find life elsewhere, but ... why? Life is already here and evolution occurs. See dinosaur. So, adaptability is an intrinsic property. Why does it have to be shown that yeast can adapt to martian conditions? Do we want to grow yeast on mars? And if the question is humans on mars, why would yeast matter? The conditions do not allow humans to live on mars, unless sheltered. Even genetically modified humans will most likely not be able to live on mars freely. The temperature alone makes this impossible:

https://en.wikipedia.org/wiki/Climate_of_Mars#Temperature

You'd need to be in a suit all of the time or in some building with higher temperature. Mars is not Earth. What is the point of having some bacteria or yeast on mars?