Uncovering the Role of the KANADI Transcription Factor ZmKAN1 in Enhancing Drought Tolerance in Maize

Drought stress causes substantial yield losses in maize, posing a serious threat to food security. Leaf adaxial-abaxial polarity development is closely associated with drought tolerance. <i>KANADI</i> (<i>KAN</i>) genes play a pivotal role in leaf polarity establishment and are likely involved in regulating drought tolerance in maize. In this study, we identified 11 <i>ZmKAN</i> genes through sequence similarity analysis and functionally characterized one of them, <i>ZmKAN1</i>, in the context of drought response. The <i>kan1-1</i> mutant exhibited enhanced drought tolerance compared to the wild-type B73. Transcriptome analysis revealed that differentially expressed genes in the mutant before and after drought stress were significantly enriched in pathways associated with drought tolerance, including "response to heat", "secondary metabolite biosynthetic process", and "plant hormone signal transduction", suggesting that <i>ZmKAN1</i> may modulate maize drought tolerance by regulating key processes such as heat response and plant hormone signaling. Furthermore, the differentially expressed genes in the wild type before and after drought stress were enriched in pathways such as "structural constituent of ribosome", "mitochondrial respiratory chain complex I", and "ribosome", suggesting that drought stress may impair ribosomal and mitochondrial functions more severely in the wild type, along with other cellular organelles. In contrast, mutants exhibited relatively stable ribosomal and mitochondrial activities, enabling them to maintain higher survival rates and enhanced drought tolerance under drought conditions. Our findings provide important insights into the molecular mechanisms underlying drought tolerance in maize and offer valuable genetic resources for breeding drought-resistant maize cultivars.