Low-intensity laser exposure enhances rice (Oryza sativa L.) growth through physio-biochemical regulation, transcriptional modulation, and microbiome alteration.

Environmental stressors significantly impact plant growth and agricultural productivity, necessitating innovative approaches to enhance crop resilience and yield. While high-intensity laser applications in agriculture have traditionally been limited to destructive purposes due to their harmful effects on plant growth, the emergence of low-intensity laser technology presents new opportunities for crop improvement. However, the molecular mechanisms underlying the beneficial effects of low-intensity laser treatment remain largely unexplored. This study investigated the effects of low-intensity laser treatment on rice seedling growth, physiological and molecular responses, and rhizosphere microbial communities. Low-intensity laser treatment (2 µmol/m²/s PPFD) significantly enhanced root and shoot growth, enhanced biomass accumulation, and improved yield parameters, with a 16.8% increase in effective panicles and 9.01% higher yield per plant. Physiological analyses revealed elevated antioxidant enzyme activities (POD and SOD) and reduced ROS levels in treated plants. Transmission electron microscopy showed improved chloroplast structure, correlating with enhanced photosynthetic efficiency. Transcriptomic analysis identified 623 differentially expressed genes, with significant enrichment in pathways related to photosynthesis, carbon metabolism, and hormone signaling. Notably upregulation was observed in photosynthesis-related genes (OsPsbB and OsCYF) and hormone signaling genes (OsWRKY114 and OsWRI1). Additionally, 16S rRNA sequencing revealed significant restructuring of rhizosphere bacterial communities in laser-treated plants, with enrichment of beneficial genera including Pseudomonas and Enterobacter. These findings establish low-intensity laser treatment as a promising tool for enhancing rice productivity through coordinated regulation of photosynthetic efficiency, stress responses, and beneficial microbiome interactions.