The Market Revolution did this in two main ways.
First, it made the North and the South more different in their economic systems. The North came to have much more of a mixed capitalist economy that grew more and more different from the South's plantation economy.
Second, the Market Revolution tied the North more closely to the West. Transportation improvements allowed for east-west transport between the West and the North, tying those two regions together and cutting the old ties between West and South. This made the South feel more isolated from the rest of the country.