By Helen Gregg

It’s on.

In response to Barnes and Noble’s price reduction on its Nook e-reader, Amazon.com Inc. quickly slashed the price on its Kindle, reported the Wall Street Journal. Barnes and Noble announced this morning that the Nook with 3G connectivity will now retail for $199, down from $259. Hours later, Amazon knocked its previously-$259 basic Kindle to $189, a clear response to the Nook’s pricing.

Both price changes are effective immediately.