Fracturing Gust's color identity is green and white (notably since its mana cost contains a hybrid (G/W) symbol, which is green and white [C.R. 107.4e]), so it can't be included in a Commander deck if Azusa is the deck's commander (since Azusa's color identity is green only) (C.R. 903.4, 903.5c) — this is so even though Fracturing Gust can be cast for 2GGG (C.R. 601.2b, 601.2f). Note that if an effect somehow lets you cast a card named Fracturing Gust (e.g., from someone else's hand) during a Commander game, you can still do so regardless of your commander's color identity (see also this thread).
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GRTitanshift[mana]RG/mana]
EDIT (Mar. 16, 2021): Correctness edit.