Devkar Vikas, D'Agostino Leonidas, Kshetry Arjun Ojha, Chen Yi, Ghose Kaushik, Lenin Yong-Villalobos, Nadaf Altafhusain B, Thirumalaikumar V P, Skirycz Aleksandra, Sonah Humira, Ma Jianxin, Stupar Robert M, Miller Anthony J, Herrera-Estrella Luis, Deshmukh Rupesh, Patil Gunvant B
Institute of Genomics for Crop Abiotic Stress Tolerance, Department of Plant and Soil Science, Texas Tech University, Lubbock, 79409, Texas, USA.
Biochemistry and Metabolism Department, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.
Plant J. 2025 Jul;123(1):e70309. doi: 10.1111/tpj.70309.
Mineral nutrient uptake and deposition profoundly influence plant development, stress resilience, and productivity. Silicon (Si), though classified as a non-essential element, significantly influences a plant's physiology, particularly in fortifying defense responses and mitigating stress. While the genetic and molecular mechanisms of Si uptake and transport are well studied in monocots, particularly rice, their role in dicot species, such as soybean, remains unclear at the cellular and molecular levels. In this study, we utilized single-nucleus RNA sequencing (snRNA-seq) to dissect cellular responses to Si accumulation in soybean leaves. We identified distinct cellular populations, including a unique Si-induced or Si-associated cell cluster within vascular cells, suggesting a specialized mechanism of Si distribution. Si treatment notably induced the expression of defense-related genes, with a pronounced enrichment in vascular cells, underscoring their pivotal role in activating plant defense mechanisms. Moreover, Si modulated the expression of genes involved in phytoalexin biosynthesis, salicylic acid, and immune receptor signaling, suggesting transcriptional priming of genes involved in defense responses. Further investigation of Si transporters revealed precise expression of an Si efflux gene in epidermal cells in response to Si treatment. We also validated the role of efflux Si transporters using a Xenopus oocyte assay and CRISPR/Cas9 genome editing of composite soybean plant roots. This study provides critical insights into the biotic stress regulatory networks influenced by Si treatment in soybean leaves at the single-cell level, thus laying the foundation for enhancing stress tolerance through optimized mineral nutrient uptake.
矿质养分的吸收和沉积对植物发育、抗逆性和生产力有着深远影响。硅（Si）虽被归类为非必需元素，但对植物生理有显著影响，尤其是在增强防御反应和减轻胁迫方面。虽然在单子叶植物尤其是水稻中，硅吸收和运输的遗传及分子机制已得到充分研究，但其在双子叶植物如大豆中的细胞和分子水平作用仍不清楚。在本研究中，我们利用单核RNA测序（snRNA-seq）剖析大豆叶片中细胞对硅积累的反应。我们鉴定出了不同的细胞群体，包括维管细胞内一个独特的硅诱导或硅相关细胞簇，这表明存在一种特殊的硅分布机制。硅处理显著诱导了防御相关基因的表达，在维管细胞中显著富集，突出了它们在激活植物防御机制中的关键作用。此外，硅调节了与植保素生物合成、水杨酸和免疫受体信号传导相关基因的表达，表明参与防御反应的基因存在转录预激活。对硅转运体的进一步研究揭示了一个硅外排基因在表皮细胞中对硅处理的精确表达。我们还通过非洲爪蟾卵母细胞试验以及对复合大豆植株根系进行CRISPR/Cas9基因组编辑，验证了外排硅转运体的作用。本研究在单细胞水平上为大豆叶片中受硅处理影响的生物胁迫调控网络提供了关键见解，从而为通过优化矿质养分吸收来提高胁迫耐受性奠定了基础。
