Calcium and calcium sensors in fruit development and ripening

Calcium ions (Ca2+) is an important element for plant cells and serve as second messengers, playing an important role in the regulation of plant physiology, specifically in postharvest fruits and vegetables. The roles of calcium and calcium-sensing receptors have been exhaustively studied in plants, and some of these receptors have been found to play a role in fruit ripening as well. However, a comprehensive overview of the manner in which calcium participates in regulating fruit development, ripening and the molecular mechanisms underlying fruit physiology and ripening have not been conducted. In this study, we reviewed the comprehensive roles of calcium in fruit development and ripening, attempting to elucidate the possible physiological and molecular mechanisms in fruit ripening. The roles of calcium sensors, including calmodulin (CaM), calmodulin-like (CML) proteins, calcineurin B-like proteins (CBL), and calcium-dependent protein kinases (CDPK), are discussed in fruit development and ripening. The interaction between the calcium signal and phytohormone signal pathways in fruit development and fruit ripening was also reviewed. The integral associations among calcium, calcium sensors, and fruit ripening were highlighted. This study provides a comprehensive overview of calcium signals in fruit development and ripening and may contribute to possible areas of interest for future research.