Calcium signaling-mediated transcriptional reprogramming during abiotic stress response in plants

Calcium (Ca²⁺) is a second messenger in plants growth and development, as well as in stress responses. The transient elevation in cytosolic Ca²⁺ concentration have been reported to be involved in plants response to abiotic and biotic stresses. In plants, Ca²⁺-induced transcriptional changes trigger molecular mechanisms by which plants adapt and respond to environment stresses. The mechanism for transcription regulation by Ca²⁺ could be either rapid in which Ca²⁺ signals directly cause the related response through the gene transcript and protein activities, or involved amplification of Ca²⁺ signals by up-regulation the expression of Ca²⁺ responsive genes, and then increase the transmission of Ca²⁺ signals. Ca²⁺ regulates the expression of genes by directly binding to the transcription factors (TFs), or indirectly through its sensors like calmodulin, calcium-dependent protein kinases (CDPK) and calcineurin B-like protein (CBL). In recent years, significant progress has been made in understanding the role of Ca²⁺-mediated transcriptional regulation in different processes in plants. In this review, we have provided a comprehensive overview of Ca²⁺-mediated transcriptional regulation in plants in response to abiotic stresses including nutrition deficiency, temperature stresses (like heat and cold), dehydration stress, osmotic stress, hypoxic, salt stress, acid rain, and heavy metal stress.