Calcium signaling is involved in diverse cellular processes in fungi.

Calcium (Ca) is a universal signalling molecule of life. The Ca signalling is an evolutionarily conserved process from prokaryotes to eukaryotes. Ca at high concentration is deleterious to the cell; therefore, cell maintains a low resting level of intracellular free Ca concentration ([Ca]). The resting [Ca] is tightly regulated, and a transient increase of the [Ca] initiates a signalling cascade in the cell. Ca signalling plays an essential role in various processes, including growth, development, reproduction, tolerance to stress conditions, and virulence in fungi. In this review, we describe the evolutionary aspects of Ca signalling and cell functions of major Ca signalling proteins in different fungi.