How can we use Blockchain for Land Registration Use Case? How and where can we integrate Blockchain in this use case? 

Say buyer and seller visits the registration office with sale deed they prepared. 
The details in the sale deed is compared by the registration analyst with the land database.If the details match the registration officer will sign off the document.
Have some good old fashioned digital signatures from buyer/seller/registration officer on the documents and use opentimestamps.org to securely timestamp it. Let all parties involved keep a copy (encrypted or not) of the documents and you're done.

You don't need a blockchain.