Maize WRKY28 interacts with the DELLA protein D8 to affect skotomorphogenesis and participates in the regulation of shade avoidance and plant architecture.

This article focuses on the role of the maize (Zea mays) WRKY transcription factor ZmWRKY28 in regulating skotomorphogenesis, the shade-avoidance response (SAR), and plant architecture. The study demonstrates that ZmWRKY28 promotes mesocotyl elongation in etiolated seedlings by directly activating the expression of the Small Auxin Up RNA gene ZmSAUR54 and the Phytochrome-Interacting Factor gene ZmPIF4.1 through binding to their promoters. The maize DELLA protein Dwarf Plant8 (D8) physically interacts with ZmWRKY28 in the nucleus and inhibits its transcriptional activation activity, indicating that ZmWRKY28 functions within the gibberellic acid (GA)-mediated signaling pathway. Functional analyses revealed that ZmWRKY28 positively regulates the SAR, influences plant height during early vegetative growth, and that its overexpression causes leaf rolling and erectness, traits potentially beneficial for high-density planting. These findings suggest that ZmWRKY28 is a key component linking GA signaling and light responses, offering a target for breeding maize cultivars with improved tolerance to shading and dense planting conditions.