Somebdy may correct my but to my knowledge, it can't be simply done with any flavor of markdown. But a little tinkering with html might help, resulting in something like this:
<pre> This is a blockquote and ==<b>this part is highlighted.</b>== </pre>
This will look like this:
This is a blockquote and ==this part is highlighted.==
If this suffices, just reorder this a bit (add a new line after the opening pre).