European Journal of Sustainable Agroecosystems

Background: Drought is one of the strongest abiotic stresses that affect global agriculture, and maize (Zea mays L.) is highly sensitive during important growth periods. As the main food crop for over 800 million people in the world, it is crucial to understand how stomatal function is regulated at the molecular level under water deficit conditions in order to ensure food security and sustainable development of crops. Stomata, the small openings in the epithelium of plants that affect exchange of gases and the process of transpiration, serve as the main link between the amount of water in the plant and need for water in the air. Their coordinated regulation in drought conditions involves a complex chain of signaling processes associated with hormones, ions and transcriptional processes.

Objective: The purpose of the study is to outline essential achievements in the development of understanding of molecular stomatal regulation of maize in drought conditions, emphasizing the role of biosynthesis of abscisic acid (ABA), its perception, and downstream signaling via the core modules PYR/PYL–PP2C–SnRK2, functioning of ion channels in guard cells, role of ROS and Ca²âº as secondary messengers of signaling processes.

Literature Sources: A thorough search of PubMed, Scopus, Web of Science, Google Scholar, and NCBI database was made for studies between 2015 and 2025 along with some referenced landmark studies.

Major Results: ABA is the main drought signal that is responsible for closing of the stomata whereby the receptor, the protein phosphatase, type 2C (PP2C), along with sucrose non-fermenting-1-related protein kinases (SnRK2) form the core signaling apparatus. Furthermore, the slow anion channel, ZmSLAC1, which is regulated by ZmOST1 and ZmCPKs through phosphorylation, carries out the cell depolarization to make the K+ leave and the stomata close. There are also maize transcription factors such as ZmNAC20, ZmNAC49, ZmWRKY79, ZmMYB31, and ZmPIF1 that modify ABA sensitivity and stomata density. The closure signal is also boosted by the calcium oscillations and ROS generated from NADPH oxidase.

Gaps in Research: Insufficient knowledge exists about guard cell signaling in maize, the relationship between epigenetics and stomatal regulation, and the practical conversion of signal target genes into a drought-tolerant maize cultivar.

Conclusion: Studies of the molecular mechanisms of stomatal control in maize allow research into more efficient use of water in crop production. Further research mixing molecular biology with crop physiology will produce maize bred for climate impact.