Genome-wide identification of NAC family and functional characterization of NtNAC236 in tobacco (Nicotiana tabacum)

Abstract

Drought stress severely limits crop growth, and NAC transcription factors (TFs) are critical for drought response. In Nicotiana tabacum, we identified 266 NAC genes, among which NtNAC236 emerged as a key drought-responsive TF based on phylogenetic and expression analyses. Overexpressing NtNAC236 in K326 enhanced its drought tolerance, and subcellular localization confirmed its nuclear role. Transcriptome and DAP-Seq analyses of NtNAC236-OE lines and WT plants revealed that NtNAC236 regulates 458 differentially expressed target genes under drought, enriched in stress-response pathways. A co-expression network further linked NtNAC236 to 43 drought-associated genes. Our findings establish NtNAC236 as a pivotal drought-resistance regulator and provide a foundation for mechanistic studies to improve crop drought tolerance.