Build launchpad PPA packages with backport version

I want to build packages for my PPA using meson. I think I figured out how to do make a working recipe. However I need meson version (>= 0.4) which is not in the release repository of xenial.

However, in the backports repository (https://launchpad.net/ubuntu/+source/meson) there is a meson with a version that is sufficient. How can I tell launchpad to build using the backports version? Is there some flag in the debian/control file I can use to tell launchpad to use the backported version?

For reference: my debian/control file:

Source: hardcode-tray

Section: misc
Priority: optional
Maintainer: ****
Build-Depends: build-essential, debhelper (>= 9), meson (>=0.40)
Standards-Version: 3.9.3
Homepage: ****

Package: hardcode-tray
Architecture: all
Depends: git, python3, python3-gi, wget, inkscape, python3-cairosvg, 

    gir1.2-rsvg-2.0, libqt4-svg, sni-qt, gir1.2-gtk-3.0, 
    ${misc:Depends}
Description: Fixes Hardcoded tray icons in Linux

the meson Build-Depends is giving me the issues...

Actually there is a two ways to install a package:

• Install a package from backports and getting dependencies from a main
  repo

apt-get install package/trusty-backports

• Install a package and all dependencies from backports repo

apt-get install -t trusty-backports package

But if you still convinced that you should do it, here https://help.launchpad.net/Packaging/PPA/BuildingASourcePackage is an instruction

Depending on other PPAs

If you want Launchpad to satisfy your package dependencies using one or more other PPAs, follow the Edit dependencies link on your PPA or the team's overview page.