Cook the wheat berries: Toast the wheat berries in a dry, heavy skillet over medium-high heat until the berries smell nutty, 5 to 6 minutes. Keep them moving as they cook.
Transfer the toasted berries to a pressure cooker, add the water and salt, attach the lid, and put over high heat until hissing begins and pressure indicator rises.
Lower heat to maintain a low hiss and full pressure, and cook for 45 minutes. Release the pressure using manufacturer's instructions or by running under cool water for a couple of minutes. The berries should have a toothy texture. Drain excess water, if necessary.
Compose the Pilaf: Heat the olive oil in a large saute pan over low heat. Add the onions and salt, and sweat until soft, about 10 minutes.
Add the garlic and continue cooking for 5 minutes.
Add the butter to the pan and melt, followed by the mushrooms and soy sauce. Increase heat to medium and continue cooking until the mushrooms release their liquid, 5 to 10 more minutes.
Add the wine and chicken broth, and simmer 5 minutes.
Add the cooked wheat berries, thyme, rosemary, and lemon zest to heat through. Adjust salt to taste.