Exogenous short-term silicon application regulates macro-nutrients, endogenous phytohormones, and protein expression in Oryza sativa L.

Abstract

BackgroundSilicon (Si) has been known to regulate plant growth; however, the underlying mechanisms of short-term exogenous Si application on the regulation of calcium (Ca) and nitrogen (N), endogenous phytohormones, and expression of essential proteins have been little understood.ResultsExogenous Si application significantly increased Si content as compared to the control. Among Si treatments, 1.0 mM Si application showed increased phosphorus content as compared to other Si treatments (0.5, 2.0, and 4.0 mM). However, Ca accumulation was significantly reduced (1.8- to 2.0-fold) at the third-leaf stage in the control, whereas all Si treatments exhibited a dose-dependent increase in Ca as determined by radioisotope 45Ca analysis. Similarly, the radioisotope 15N for nitrogen localization and uptake showed a varying but reduced response (ranging from 1.03–10.8%) to different Si concentrations as compared to 15N application alone. Physiologically active endogenous gibberellin (GA1) was also significantly higher with exogenous Si (1.0 mM) as compared to GA20 and the control plants. A similar response was noted for endogenous jasmonic and salicylic acid synthesis in rice plants with Si application. Proteomic analysis revealed the activation of several essential proteins, such as Fe-S precursor protein, putative thioredoxin, Ser/Thr phosphatase, glucose-6-phosphate isomerase (G6P), and importin alpha-1b (Imp3), with Si application. Among the most-expressed proteins, confirmatory gene expression analysis for G6P and Imp3 showed a similar response to those of the Si treatments.ConclusionsIn conclusion, the current results suggest that short-term exogenous Si can significantly regulate rice plant physiology by influencing Ca, N, endogenous phytohormones, and proteins, and that 1.0 mM Si application is more beneficial to plants than higher concentrations.Electronic supplementary materialThe online version of this article (10.1186/s12870-017-1216-y) contains supplementary material, which is available to authorized users.

Elevated atmospheric CO2 suppresses jasmonate and silicon‐based defences without affecting herbivores

“…As JA is a transient signalling molecule, it quickly spikes in response to a perceived stress over minutes to hours and then decreases rapidly in plant tissues (Glauser et al, 2008; Hickman et al, 2017). These results are similar to previous studies showing lower JA in Si+ plants under various stress conditions (Kim et al, 2014, 2016), despite higher JA levels in non‐stressed, Si+ plants (Jang et al, 2018). In contrast, Ye et al (2013) found that Si had a priming effect, such that Si supplemented plants had higher endogenous JA when challenged.…”

“…polyphenol oxidase and catalase), reducing reactive oxygen species (ROS) and thus the downstream production of JA (see review by Kim, Khan, & Lee, 2016). Conversely non‐stressed plants that have been supplemented with Si have higher endogenous JA levels compared to control plants (Jang, Kim, Khan, Na, & Lee, 2018; Kim et al, 2014).…”

Silicon Compensates Phosphorus Deficit-Induced Growth Inhibition by Improving Photosynthetic Capacity, Antioxidant Potential, and Nutrient Homeostasis in Tomato

“…Silicon (Si) is the second most abundant element in earth crust, which can be taken up by higher plants from the rhizospheric soil solution, mostly, in the form of silicic acid (H 4 SiO 4 ) [12]. Over the last several decades, Si has been a focal point for plant scientists for its remarkable role in regulating plant growth and stress responses [13]. However, the role of exogenous Si in photosynthesis, ROS metabolism, and nutrient homeostasis in tomato plants has been little understood.…”

“…Almost all terrestrial plant species accumulate Si in different tissues, but the mechanism of Si accumulation still remains unclear [12]. Si is a beneficial element that promotes growth and development in a number of plant species [13]. However, benefits from Si largely depend on the presence of an efficient Si transport system.…”

“…It is believed that the positive effects of Si on plants are due to its deposition in roots, leaves, stems, and so on, which strengthens those tissues and creates physical barriers [12]. Si fertilization as a means for nutrient management has shown to increase rice productivity in Japan [13]. Si also improves plant tolerance to a wide range of biotic and abiotic stresses, such as drought, salinity, heat, cold, metal toxicity, and nutrient stress [11,[14][15][16][17].…”