Journal Article

Silicon-induced thermotolerance in Solanum lycopersicum L. via activation of antioxidant system, heat shock proteins, and endogenous phytohormones

Al-Harrasi, Ahmed, Khan, Adil, Imran, Muhammad, Numan, Muhammad, Khan, Abdul Latif, Kim, Yoon-Ha, Bilal, Saqib, Asaf, Sajjad, Al-Rawahi, Ahmed, Lee, In-Jung

2020

Overview

Background Abiotic stresses (e.g., heat or limited water and nutrient availability) limit crop production worldwide. With the progression of climate change, the severity and variation of these stresses are expected to increase. Exogenous silicon (Si) has shown beneficial effects on plant growth; however, its role in combating the negative effects of heat stress and their underlying molecular dynamics are not fully understood. Results Exogenous Si significantly mitigated the adverse impact of heat stress by improving tomato plant biomass, photosynthetic pigments, and relative water content. Si induced stress tolerance by decreasing the concentrations of superoxide anions and malondialdehyde, as well as mitigating oxidative stress by increasing the gene expression for antioxidant enzymes (peroxidases, catalases, ascorbate peroxidases, superoxide dismutases, and glutathione reductases) under stress conditions. This was attributed to increased Si uptake in the shoots via the upregulation of low silicon (SlLsi1 and SlLsi2) gene expression under heat stress. Interestingly, Si stimulated the expression and transcript accumulation of heat shock proteins by upregulating heat transcription factors ( Hsfs ) such as SlHsfA1a-b, SlHsfA2-A3, and SlHsfA7 in tomato plants under heat stress. On the other hand, defense and stress signaling-related endogenous phytohormones (salicylic acid [SA]/abscisic acid [ABA]) exhibited a decrease in their concentration and biosynthesis following Si application. Additionally, the mRNA and gene expression levels for SA ( SlR1b1, SlPR-P2, SlICS, and SlPAL ) and ABA ( SlNCEDI ) were downregulated after exposure to stress conditions. Conclusion Si treatment resulted in greater tolerance to abiotic stress conditions, exhibiting higher plant growth dynamics and molecular physiology by regulating the antioxidant defense system, SA/ABA signaling, and Hsfs during heat stress.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Abscisic acid / Abscisic Acid - metabolism / Agriculture / Anions / Antioxidant / antioxidant activity / Antioxidants / Antioxidants (Nutrients) / Antioxidants - metabolism / Antioxidants - physiology / ascorbate peroxidase / Ascorbic acid / Biomedical and Life Sciences / Biosynthesis / catalase / Chlorophyll - metabolism / Climate change / Crop production / EDTA / Enzymes / Ethanol / Gene expression / Gibberellins / Global temperature changes / Glutathione / Heat / Heat shock protein / Heat shock proteins / Heat stress / Heat tolerance / Heat-Shock Proteins - metabolism / Heat-Shock Proteins - physiology / Hormones / Humidity / Life Sciences / Malondialdehyde / Mass spectrometry / Moisture content / Molecular dynamics / Mosses / Nutrient availability / Oxidative stress / Photosynthesis / Photosynthetic pigments / Physiological aspects / Phytohormones / phytomass / Pigments / Plant biomass / Plant growth / Plant Growth Regulators - metabolism / Plant Growth Regulators - physiology / Plant hormones / Plant Proteins - metabolism / Plant Proteins - physiology / Plant Sciences / Plant-abiotic interactions / Productivity / Real-Time Polymerase Chain Reaction / Reductases / Research Article / RNA / Salicylic acid / Scientific imaging / Seeds / Shoots / Signaling / Silicon / Silicon - pharmacology / Solanum lycopersicum / Solanum lycopersicum - drug effects / Solanum lycopersicum - metabolism / Solanum lycopersicum - physiology / Solanum lycopersicum L / stress tolerance / Superoxide / Superoxide anions / superoxide dismutase / Superoxides / Temperature tolerance / Thermotolerance - drug effects / Tomatoes / Transcription factors / Tree Biology / Water content