add_filter('wp_mail_from', 'new_mail_from');
add_filter('wp_mail_from_name', 'new_mail_from_name');

function new_mail_from($old) {
 return 'no-reply@deine-mailadresse.de';
}

function new_mail_from_name($old) {
 return 'deine-domain.de';
}