One of the options listed here Truffle FAQ is to put the truffle in a paper bag in the fridge. I have no experience storing fresh truffles (only canned) so I can't swear to it as an option. I can say that the paper-bag-in-the-fridge method works very well for mushrooms. The link goes on to say that the writers of the site do not recommend storing the truffle in rice, that it dries out the truffle and sacrifices perfume to the rice. That's a bit disappointing as I would want to make risotto from the rice.
Originally, I posted the link as a kind of answer. I can't in good conscious do that because the answer on that site includes the possibility of storing the truffle in oil. The site does mention that such storage would be need to be short term only. It doesn't mention that the risk is botulism, nor does it say how long a truffle can be safely stored that way. As such, I cannot recommend the method, or, really, the site itself.
Another possibility mentioned by the suspect site is freezing the truffle in a jar. Hmmm. Mushrooms take a big hit in quality by freezing. If you really need long-term storage of a truffle, it seems to me that you aren't adequately excited by a very cool ingredient.
So, a paper bag in the fridge is my answer.
As far as transit, I would stuff the truffle and its paper bag into a jar, protecting the truffle from moisture loss and trauma.