DSD1/ZmICEb regulates stomatal development and drought tolerance in maize

Wenqi Zhou, Jun Yin, Yuqian Zhou, Yongsheng Li, Haijun He, Yanzhong Yang, Xiaojuan Wang, Xiaorong Lian, Xiaoyun Dong, Zengke Ma, Liang Chen, Suiwen Hou

J Integr Plant Biol.; 2025 Jun; 67(6):1487-1500. doi: 10.1111/jipb.13890. 

Abstract

Maize (Zea mays L.) growth and yield are severely limited by drought stress worldwide. Stomata play crucial roles in transpiration and gas exchange and are thus essential for improving plant water-use efficiency (WUE) to help plants deal with the threat of drought. In this study, we characterized the maize dsd1 (decreased stomatal density 1) mutant, which showed defects in stomatal development, including guard mother cell differentiation, subsidiary cell formation and guard cell maturation. DSD1 encodes the basic helix-loop-helix transcription factor INDUCER OF CBF EXPRESSION b (ZmICEb) and is a homolog of ICE1 in Arabidopsis (Arabidopsis thaliana). DSD1/ZmICEb is expressed in stomatal file cells throughout stomatal development and plays a conserved role in stomatal development across maize and Arabidopsis. Mutations in DSD1/ZmICEb dramatically improved drought tolerance and WUE in maize and reduced yield losses under drought conditions. Therefore, DSD1/ZmICEb represents a promising candidate target gene for the genetic improvement of drought tolerance in maize by manipulating stomatal density.

See https://pubmed.ncbi.nlm.nih.gov/40105588/

Figure 2:

Stomatal development process in dsd1‐1 mutant

(A) Diagram of stomatal development in the developmental zone of maize leaf, showing Stages I to V as follows. Stage I, stomatal file is established in the protodermal cells. Stage II, an asymmetric division produces a smaller guard mother cell (GMC). Stage III, GMCs mature and induce the formation of subsidiary mother cells (SMCs) from laterally adjacent cells, which then divide asymmetrically to form subsidiary cells (SCs). Stage IV, GMCs undergo symmetric division to form early guard cells (GCs). Stage V, these GCs and their SCs differentiate to form a mature stomatal complex. Confocal images of the five main stomatal developmental stages in wild‐type (B) and dsd1‐1 (C). A portion of GMCs in dsd1‐1 stop developing at stage III. The white arrow highlights arrested GMCs in the stomatal development of dsd1‐1. Scale bar, 10 μm in (B), (C).