Explore around a bit. Every mushroom has a symbol on it. You'll see gates that have this symbol and a combination of colours that should be used in the mushroom with the respective symbol.
You just have to play a minigame before it gives you the answers.
Thank you for the answer but I think you told how to progress the area.
I was asking how to open gates in mushrooms and the answer is to play mushroom smacking minigame fast enough to complete all rounds. If you succeed the light above the gate will glow up.
