What is different about the way the genus and species names are written compared to the other taxa?

The way genus and species name are written are different from other taxa as both the genus and species name should be in italics and the first letter of genus name should be in capital and other letters should be in small and the species name should also be in small letters.

This rule is called binomial nomenclature and this rule does not follow to other taxa of the hierarchy so they are not italicized. This rule avoid confusion generated by common names by giving them a scientific name which is same and unique in every part of world.  

Example: Panthera leo is scientific name of lion.