Comparative study on the influence of silicon and selenium to mitigate arsenic induced stress by modulating TCA cycle, GABA, and polyamine synthesis in rice seedlings.

Susmita Das,Asok K. Biswas,Barsha Majumder

doi:10.1007/s10646-022-02524-8

Abstract

Arsenic contamination of groundwater is a major concern for its usage in crop irrigation in many regions of the world. Arsenic is absorbed by rice plants mainly from arsenic contaminated water during irrigation. It hampers growth and agricultural productivity. The aim of the study was to mitigate the toxic effects of arsenate (As-V) [25 μM, 50 μM, and 75 μM] by silicon (Si) [2 mM] and selenium (Se) [5 μM] amendments on the activity of the TCA cycle, synthesis of γ-aminobutyric acid (GABA) and polyamines (PAs) in rice (Oryza sativa L. cv. MTU-1010) seedlings and to identify which chemical was more potential to combat this threat. As(V) application decreased the activities of tested respiratory enzymes and increased the levels of organic acids (OAs) in the test seedlings. Application of Si with As(V) and Se with As(V) increased the activities of respiratory enzymes and the levels of OAs. The effects were more pronounced during Si amendments. The activities of GABA synthesizing enzymes along with accumulation of GABA were increased under As(V) stress. During joint application of Si with As(V) and Se with As(V) the activity and the level of said parameters were decreased that indicating defensive role of these chemicals to resist As(V) toxicity in rice and Si amendments showed greater potential to reduce As(V) induced damages in the test seedlings. PAs trigger tolerance mechanism against As(V) in plants. PAs such as putrescine, spermidine and spermine were synthesized more during Si and Se amendments in As(V) contaminated rice seedlings to combat the toxic effects of As(V). Si amendments substantially modulated the toxic effects caused by As(V) over Se amendments in the As(V) challenged test seedlings. Thus, in future application of Si enriched fertilizer will be beneficial to grow rice plants with normal vigor in arsenic contaminated soil.

Highlights

The world is advancing in science and technology
Organic acids produced in TCA cycle are important to carry out different biochemical pathways in cellular metabolism, acting as metabolically active solutes for osmotic adjustment leads to adaptation under different environmental stresses in plants (Xu et al 2013, Nunes-Nesi et al 2013)
As(V) treatment adversely affected the respiratory cycle by increasing the levels of organic acids (OAs) and decreasing the activities of its synthesizing enzymes in the test seedlings

Summary

Introduction

The world is advancing in science and technology. poor control is recurrently disturbing the ecosystem and environment of our green earth. The increasing volume of different heavy metals in groundwater is becoming a common cause of environmental and ecological toxicity across the globe, affecting agriculture and crop production in a large extend; these, in turn, further put the human food safety and health at risk One common such carcinogenic metal is arsenic (As) which has overreached the tolerable limit (> 0.01 mg L− 1) in groundwater of many parts of the world, including Bangladesh (Das et al 2009) and India especially West Bengal (Dey et al 2014). A metalloid present in soil as silicic acid ranging from 0.1 mM to 2 mM concentrations (Bogdan et al 2008) It is accumulated by crops including rice and exerts beneficial roles in growth, yield and productivity by elevating tolerability under abiotic and biotic stresses (Singh et al 2011; Soundararajan et al 2014; Adrees et al 2015; Tripathi et al 2016; Pontigo et al 2017). In the report of Ulhassan et al (2019b), it was noted that Se plays double role in physicochemical aspects in Brassica napus like in lower dose (25 μM) Se increased growth and photosynthesis but in higher dose (50–100 μM), it reduced growth, biomass, nutrient uptake and photosynthetic activities in Brassica napus

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