ZmCLA4 regulates leaf angle through multiple hormone signaling pathways in maize.

Leaf angle (LA) is an important agronomic trait in cereals that shares a close relationship with crop architecture and grain yield. Although it has been previously reported that ZmCLA4 can influence LA, the underlying mechanism of it remains unclear. In this study, we used Gal4-LexA/UAS system and transactivation analysis to demonstrate that ZmCLA4 is a transcriptional repressor that regulates LA. DNA affinity purification sequencing (DAP-Seq) analysis revealed that ZmCLA4 mainly binds to the promoters containing the EAR motif (CACCGGAC) as well as two motifs (CCGARGS and CDTCNTC) to inhibit the expression of its target genes. Further analysis of ZmCLA4 target genes indicated that ZmCLA4 functions as a hub of multiple plant hormone signaling pathways because ZmCLA4 was found to directly bind to the promoters of multiple genes including ZmARF22 and ZmIAA26 in the auxin transport pathway, ZmBZR3 in the brassinosteroid signaling pathway, two ZmWRKY genes involved in abscisic acid metabolism, ZmCYP genes (ZmCYP75B1, ZmCYP93D1) related to jasmonic acid metabolism, and ZmABI3 involved in the ethylene response pathway. Overall, our work provides deep insights into the regulatory network of ZmCLA4 in controlling LA in maize.