Seed biopriming with Bacillus nematocida enhances drought tolerance in maize via regulation of stress-responsive genes

Maize (Zea mays L.), a globally important cereal, is highly vulnerable to climate-induced drought stress. This study evaluated seed biopriming with Bacillus nematocida as a strategy to enhance drought tolerance through molecular reprogramming. Maize seeds were bioprimed and subjected to drought stress under greenhouse conditions, and the expression of twelve drought-responsive genes was analyzed via RT-qPCR. Biopriming strongly upregulated stress-related genes, including PLD (60-fold), PYL1 (63-fold), SLAH1 (11-fold), and OST1 (7-fold) under combined drought + biopriming, while Peroxidase and ZmPP2CA were markedly suppressed. These transcriptional shifts indicate enhanced ABA signaling, ion homeostasis, and reduced oxidative stress load. Overall, Bacillus nematocida biopriming conferred a > 50-fold activation of key drought regulators, highlighting its potential as a sustainable approach to improve maize resilience under water-limited conditions.