Replace backticks in WordPress posts, topics, replies, etc with <pre lang="PHP"></pre> so WP-Syntax will highlight it.

gistfile1.txt

/*
  Switch `` with <pre lang="PHP"></pre>
*/
function pmpro_code_wrap($content)
{
	$content = preg_replace("/`(.*?)`/s", '<pre lang="PHP">$1</pre>', $content);
	
	return $content;
}
add_filter("the_content", "pmpro_code_wrap", -1);