Topic: boron toxicity in semi-arid crops: the overlooked metalloid in abiotic stress

Boron (B) is an essential micronutrient, yet its excess induces phytotoxicity, especially in semi-arid and alkaline soils, severely constraining crop productivity. This review delineates the physiological, biochemical, and molecular responses of plants to B toxicity, highlighting oxidative stress, membrane disruption, metabolic imbalance, and photosynthetic impairment as primary consequences. Multi-omics studies, including transcriptomics, proteomics, and metabolomics, have identified key components of B tolerance, such as BOR and NIP transporters, antioxidant enzymes, and stress-inducible proteins. Proteomic investigations reveal tissue-specific responses, with the upregulation of detoxification proteins, SA-dependent defence proteins, and transcriptional regulators like RING1B, which is also implicated in stem cell maintenance. Emerging evidence underscores the role of epigenetic modifications, DNA methylation, and histone acetylation in modulating B-responsive gene expression. However, the absence of high-resolution spatial mapping of B toxicity zones and limited access to high-throughput phenotyping platforms hinder progress in breeding resilient genotypes. Additionally, the interplay between B toxicity and climate change remains underexplored, despite its likely influence on B solubility and plant uptake. Advancements in nanotechnology and microbiome engineering present novel strategies for mitigation, including nano-sensors for real-time B detection, nano-formulations for controlled delivery, and beneficial microbes for enhancing plant tolerance. Integrating these tools with precision breeding and systems biology offers a sustainable framework to counteract B toxicity. This review advocates for a transdisciplinary approach combining spatial analytics, molecular insights, and ecological resilience to manage B toxicity and ensure long-term agricultural sustainability.