Regulatory mechanisms and breeding strategies for crop drought resistance

Drought is a primary abiotic stress affecting crops, leading to plant stomatal closure, reduced photosynthetic capacity, and reduced yields or even harvest failure. Severe drought can adversely impact agricultural production, ecosystems, and socio-economic capacities. Recently, researchers have studied the regulatory mechanisms of crop drought resistance and cloned hundreds of genes via genetic and molecular approaches. However, a limited number of the cloned genes have been successfully employed in drought resistance breeding, suggesting that drought resistance regulation is too complex. More work must be done to fully understand the regulatory networks of drought responses to breed drought-resistant and high-yield crop varieties. This review outlines the current achievements in investigating crop drought responses, particularly regulation by phytohormones and regulation of genes at transcriptional, post-translational, and epigenetic levels in crop drought responses. Finally, we examine the problems and potential solutions in breeding crop drought resistance and propose strategies for crop drought resistance improvement.