Role of Silicon in Plants

Silicon (Si) is the second most abundant element in the earth crust after oxygen. Silicon has gained increasing attention in agriculture in recent years because of its beneficial effects in several crop species. Silicon fertilization is now viewed as a sustainable alternative to provide tolerance against biotic and abiotic stresses that represent major constraints for crop production worldwide. The beneficial effects of Si to improve resistance against several biotic and abiotic stresses are well documented and these benefits derived from Si are often correlated with the amount of Si uptake by plants. However, in spite of the relative abundance of Si in soils, plant-available Si is often limited in most soil-types. For this reason, a better molecular understanding of Si uptake in plants is important to maximize the benefits derived from Si fertilization. The potential of a given plant species to actively uptake Si in the form of silicic acid, the only form a plant can extract from the soil, depends on its genetic predisposition. Therefore, genetic and genomic analyses provide useful tools to decipher the mechanisms that will enhance a plant potential to respond to Si fertilization. Currently, two major transporters involved in the influx (Lsi1) and efflux (Lsi2) transport of Si in rice (and a few other species) from soil have been discovered together with two other transporters (Lsi3 and Lsi6) controlling Si distribution in plants. However, identification of similar transporter genes and their role in Si uptake and distribution in other plants known to benefit from Si remains limited, especially in dicot species. Similarly, a clear understanding of the molecular mechanisms by which Si confers protection against biotic and abiotic stresses in planta remains elusive. Recent studies conducted in model species like rice and Arabidopsis have offered critical elements aimed at elucidating the possible mechanisms involved Si transport and stress resistance, but additional studies using different approaches from plant physiology, molecular biology, plant pathology and agronomy will contribute to a unifying understanding of Si properties.
This Research Topic will provide a timely overview of the role and importance of Si in plants. It will also cover endeavours including functional evaluation of transporters involved in Si uptake and transport in plant species through transgenic approaches, genomic approaches and transcriptome profiling, protein structure prediction, and mutagenesis. Identification of candidate genes involved in Si-mediated responses in plants through QTL mapping and GWAS will also further our general knowledge of Si. We eagerly welcome reviews, mini-reviews, opinions and original articles related to the role of Si in plants and its potential benefits in agriculture.