Role of Silicon in Mediating Salt Tolerance in Plants: A Review

Abstract

Salt stress is a major threat for plant growth worldwide. The regulatory mechanisms of silicon in alleviating salt stress have been widely studied using physiological, molecular genetics, and genomic approaches. Recently, progresses have been made in elucidating the alleviative effects of silicon in salt-induced osmotic stress, Na toxicity, and oxidative stress. In this review, we highlight recent development on the impact of silicon application on salt stress responses. Emphasis will be given to the following aspects. (1) Silicon transporters have been experimentally identified in different plant species and their structure feature could be an important molecular basis for silicon permeability. (2) Silicon could mediate salt-induced ion imbalance by (i) regulating Na+ uptake, transport, and distribution and (ii) regulating polyamine levels. (3) Si-mediated upregulation of aquaporin gene expression and osmotic adjustment play important roles in alleviating salinity-induced osmotic stress. (4) Silicon application direct/indirectly mitigates oxidative stress via regulating the antioxidant defense and polyamine metabolism. (5) Omics studies reveal that silicon could regulate plants’ response to salt stress by modulating the expression of various genes including transcription factors and hormone-related genes. Finally, research areas that require further investigation to provide a deeper understanding of the role of silicon in plants are highlighted.

Silicon amendment induces synergistic plant defense mechanism against pink stem borer (Sesamia inferens Walker.) in finger millet (Eleusine coracana Gaertn.)

“…Moreover, EcLsi2 and EcLsi3 might have evolved from EcLsi1 and/or EcLsi6 and/or from both genes due to a duplication event during evolution. The phylogenetic analysis of silicon transporter genes was found to be useful to establish the evolutionary relatedness and divergence in different plant species 32,39 .…”

Root Response to Drought Stress in Rice (Oryza sativa L.)

“…The plant organs, such as leaf and root, orchestrate defense mechanisms (internal or external) in response to abiotic stress [9][10][11]. Root is the first organ exposed to water stress because water stress results from an insufficient or excessive level of water in the soil [7,8,[12][13][14].…”

Genome-Wide Identification, Structure Characterization, and Expression Profiling of Dof Transcription Factor Gene Family in Wheat (Triticum aestivum L.)

“…Many studies have shown that Dof transcription factors are involved in regulation of biotic and abiotic stress response [20,21]. For example, the action of SlCDF1 and SlCDF3, two Dof transcription factors in tomato, caused improved drought and salt stress tolerance in transgenic plants [22]; and CDF3, a cycling DOF factor in Arabidopsis, promoted drought, cold, and osmotic stress tolerance [23].Crops are challenged by many types and levels of stresses such as salt and drought [24,25]. As one of the world's most important staple crops, wheat (Triticum aestivum L.) is affected by various kinds of stress that limits the achievement of yield potential [26].…”

“…Crops are challenged by many types and levels of stresses such as salt and drought [24,25]. As one of the world's most important staple crops, wheat (Triticum aestivum L.) is affected by various kinds of stress that limits the achievement of yield potential [26].…”