The NAC transcription factor ZmNAC24: from aquaporin regulation to genome-wide targets and plant development

ABSTRACT: Plasma membrane intrinsic proteins (PIPs) are channels facilitating the transport of water and small solutes across the plasma membrane. In plants, PIPs are crucial for processes such as hydraulic regulation in roots and leaves, cell expansion, and organ development. The molecular mechanisms underlying PIP transcriptional regulation remain poorly understood. In an expression quantitative trait loci (eQTL) study conducted in our laboratory, we investigated the expression regulation of four PIP genes in maize leaves and identified ZmNAC24 as a transcriptional regulator of the ZmPIP2;5 gene. NAC TFs are one of the largest plant-specific TF families, known for their roles in plant development and stress responses. We demonstrated that ZmNAC24 localizes to the nucleus and transactivates the ZmPIP2;5 promoter. Maize plants with a transposon-induced ZmNAC24 mutation exhibited significantly reduced ZmPIP2;5 expression, stunted growth, smaller leaves, and an overall decrease in plant size. This phenotype suggested that the effects cannot be solely attributed to the reduced PIP2;5 expression. Further exploration using DNA affinity purification sequencing (DAP-seq) enabled us to map ZmNAC24 binding events, and we identified 1,119 peaks on the primary root gDNA. Putative target genes were assigned to peaks located within 3 kb upstream of the transcription start site and 1 kb downstream of the transcription termination site, resulting in 420 potential ZmNAC24 target genes. These targets are enriched in function related to shoot apical meristem development, auxin response, and reproductive system development, highlighting the importance of ZmNAC24 in plant development. NAC24 binds the CACG consensus sequence as a monomer or dimer, as confirmed by electrophoretic mobility shift assay (EMSA). Interestingly, ZmNAC24 does not directly bind the ZmPIP2;5 promoter in this assay.

ORGANISM(S): Zea mays

PROVIDER: GSE294250 | GEO | 2026/05/27

REPOSITORIES: GEO