Silicon Regulates Potential Genes Involved in Major Physiological Processes in Plants to Combat Stress

Abstract

Silicon (Si), the quasi-essential element occurs as the second most abundant element in the earth's crust. Biological importance of Si in plant kingdom has become inevitable particularly under stressed environment. In general, plants are classified as high, medium, and low silicon accumulators based on the ability of roots to absorb Si. The uptake of Si directly influence the positive effects attributed to the plant but Si supplementation proves to mitigate stress and recover plant growth even in low accumulating plants like tomato. The application of Si in soil as well as soil-less cultivation systems have resulted in the enhancement of quantitative and qualitative traits of plants even under stressed environment. Silicon possesses several mechanisms to regulate the physiological, biochemical, and antioxidant metabolism in plants to combat abiotic and biotic stresses. Nevertheless, very few reports are available on the aspect of Si-mediated molecular regulation of genes with potential role in stress tolerance. The recent advancements in the era of genomics and transcriptomics have opened an avenue for the determination of molecular rationale associated with the Si amendment to the stress alleviation in plants. Therefore, the present endeavor has attempted to describe the recent discoveries related to the regulation of vital genes involved in photosynthesis, transcription regulation, defense, water transport, polyamine synthesis, and housekeeping genes during abiotic and biotic stress alleviation by Si. Furthermore, an overview of Si-mediated modulation of multiple genes involved in stress response pathways such as phenylpropanoid pathway, jasmonic acid pathway, ABA-dependent or independent regulatory pathway have been discussed in this review.

Silicon (Si) biochar for the mitigation of arsenic (As) bioaccumulation in spinach ( Spinacia oleracean ) and improvement in the plant growth

“…According to the results of Debona et al (2017), Si regulates stress from metal toxicity by modulating the pH range of soil or changing metal speciation while Xiao et al (2014) suggested metal co-precipitation and the formation of inorganic crystals (facilitated by Si) in carbonaceous materials like biochar as a mechanism to abate metal toxicity. Recently, Manivannan and Ahn (2017) suggested the involvement of Si in regulating genes that affect photosynthesis during metal toxicity and the modulation of the expression of housekeeping genes during disease infection. Genes involved in water uptake and transportation and those involved in the expression of defense response in plants are also modulated by Si (Manivannan and Ahn, 2017).…”

“…Recently, Manivannan and Ahn (2017) suggested the involvement of Si in regulating genes that affect photosynthesis during metal toxicity and the modulation of the expression of housekeeping genes during disease infection. Genes involved in water uptake and transportation and those involved in the expression of defense response in plants are also modulated by Si (Manivannan and Ahn, 2017).…”

Silicon accumulation and its effect on agricultural traits and anthracnose incidence in lignocellulosic sorghum

“…The Si accumulation also affects the plant structure, increasing the tissue structure firmness, reducing lodging and plant breaking, besides contributing to a greater crop yield (Epstein 1999, Korndörfer & Lepsch 2001, Hattori et al 2005, Ahmed et al 2014, Manivannan & Ahn 2017. A reduction in the percentage of lodged sorghum plants was observed in the soil fertilized with Si.…”

“…Silicon accumulation is associated with plant structural features that increase the structural rigidity of tissues and reduce lodging. In addition, Si promotes the formation of more upright leaves, decreasing self-shading, increasing the leaf area (and consequently the photosynthesis efficacy) and plant growth, as well as leading to a higher crop yield (Epstein 1999, Korndörfer & Lepsch 2001, Hattori et al 2005, Ahmed et al 2014, Manivannan & Ahn 2017.…”

Silicon Mechanisms to Ameliorate Heavy Metal Stress in Plants

“…A previously conducted experiment shows that Si can decrease OH hydroxyl radical accumulation in cucumber leaves by reducing the free apoplastic Mn +2 [ 19 ]. One of the other protective roles of silicon is regulating internal water in plants [ 22 ] so that the accumulation of silicon in epidermal tissue preserves water in the transpiration process [ 23 ]. Generally, plants tend to accumulate heavy metals, such as cadmium, in the root more than shoot and stem [ 24 ].…”