Researchers examined hundreds of soil samples to uncover why the expensive fungi are thriving in the country Study author Gregory Bonito collects truffles in Australia.  Greg Bonito / Michigan State University Black truffles are coveted by foodies and chefs around the world for their rich, earthy aroma. The rare mycorrhizal fungi ( Tuber melanosporum ), which grow close to the root of trees, are native to the limestone-rich soils of Southern Europe. But one of the world’s largest producers of truffles is actually Australia. Truffles were introduced to Australia 25 years ago, when the first host trees with T. melanosporum spores were planted there. Since then, the country's truffle industry has boomed, and Australia is now the fourth-largest producer of the prized fungi, with some orchards’ yields surpassing those of European countries. Now, a new study explains why black truffles have managed to thrive there.…