Aluminum impairs morphogenic transition and stimulates H⁺ transport mediated by the plasma membrane ATPase of Yarrowia lipolytica

The effect of aluminum on dimorphic fungi Yarrowia lipolytica was investigated. High aluminum (0.5-1.0 mM AlK(SO₄)₂) inhibits yeast-hypha transition. Both vanadate-sensitive H⁺ transport and ATPase activities were increased in total membranes isolated from aluminum-treated cells, indicating that a plasma membrane H⁺ pump was stimulated by aluminum. Furthermore, Al-treated cells showed a stronger H⁺ efflux in solid medium. The present results suggest that alterations in the plasma membrane H⁺ transport might underline a pH signaling required for yeast/hyphal development. The data point to the cell surface pH as a determinant of morphogenesis of Y. lipolytica and the plasma membrane H⁺-ATPase as a key factor of this process.