Contents lists available at ScienceDirect Ecotoxicology and Environmental Safety journal homepage: www.elsevier.com/locate/ecoenv Exogenous application of methyl jasmonate alleviates arsenic toxicity by modulating its uptake and translocation in rice (Oryza sativa L.) Giti Verma a,∗∗ , Dipali Srivastava a , Shiv Narayan b,1 , Pramod Arvind Shirke b,1 , Debasis Chakrabarty a,∗,1 a Molecular Biology and Biotechnology Division, Council of Scientific & Industrial Research–National Botanical Research Institute (CSIR-NBRI), Lucknow, 226001, India b Plant Physiology Laboratory, Council of Scientific & Industrial Research –National Botanical Research Institute (CSIR-NBRI), Lucknow, 226001, India ARTICLE INFO Keywords: Arsenic Methyl jasmonate Rice Plant stress Gene expression ABSTRACT Methyl jasmonate (Me-JA) is a plant growth regulator known for modulating plant responses to various abiotic and biotic stresses. The unavoidable arsenic (As) contamination in rice (Oryza sativa) results in reduced crop yield and greater carcinogenic risk to humans. The present work examines the significance of Me-JA induced molecular signaling and tolerance towards arsenic toxicity in rice. The arsenite (AsIII; 25 μM) stress hampered the overall growth and development of the rice seedling. However, the co-application (25 μM AsIII+0.25 μM Me-JA) resulted in increased biomass, chlorophyll content, enhanced antioxidant enzyme activities as compared to AsIII treated plants. The co-application also demonstrated a marked decrease in malondialdehyde content, electrolyte leakage and accumulation of total AsIII content (root + shoot) as compared to AsIII treated plants. The co-application also modulated the expression of genes involved in downstream JA signaling pathway (OsCOI, OsJAZ3, OsMYC2), AsIII uptake (OsLsi1, OsLsi2, OsNIP1;1, OsNIP3;1), translocation (OsLsi6, and OsINT5) and detoxification (OsNRAMP1, OsPCS2, and OsABCC2) which revealed the probable adaptive response of the rice plant to cope up arsenic stress. Our findings reveal that Me-JA alleviates AsIII toxicity by modulating sig- naling components involved in As uptake, translocation, and detoxification and JA signaling in rice. This study augments our knowledge for the future use of Me-JA in improving tolerance against AsIII stress. 1. Introduction Arsenic (As) is a ubiquitous, non-essential, and toxic metalloid. As has been characterized as Class I carcinogen by the World health or- ganization (WHO). The problem of As toxicity is alarming in South and Southeast Asia, where As pollution is prevalent in ground and surface water and soil as well (Shri et al., 2019). In soil, As is present in in- organic form i.e. arsenate (AsV) and arsenite (AsIII). The unavoidable As contamination by soil and irrigation of crop plants not only restricts the plant growth and yields but also leads to As accumulation, which in the long run, leads to the contamination of the food chain. The con- sumption of these As laden food crops leads to arsenicosis and, even- tually, chronic As poisoning (Shri et al., 2019). This toxicity is parti- cularly evident in rice cultivation as AsIII is the prevalent form of As in flooded/anaerobic conditions of paddy fields. The health risks posed by As toxicity can be alleviated by strategically developing crops with less As accumulation in edible parts. Arsenate has been identified as phosphate analog, and thus, the plant system fails to discriminate between them, initially by various phosphate transporters, and upon entry into the cell, AsV interferes with various cellular processes (Lindsay et al., 2017). Similarly, AsIII exists as arsenous acid in a solution form, mimics both boric acid as well as silicic acid. Thus, arsenite uptake takes place through the subfamily of the aquaporins, nodulin-26-like intrinsic proteins (NIPs; Ma et al., 2007). In rice, AsIII uptake majorly occurs through OsNIP2;1, which is equivalent to silicon (Si) influxer low silicon 1 (OsLsi1). Further uptake towards the stele is maintained by the efflux transporter OsLsi2. AsIII has a strong affinity to bind sulfhydryl groups, consequently altering their folding pattern and functionality, hampering protein-protein in- teractions (Cline et al., 2003) and activities of various metabolic and regulatory enzymes and binding of transcription factors (TF). With the work done in the past few years, it has been identified that As detox- ification mechanism is done either with glutathione (GSH) and/or with phytochelatins (PCs) and then this complex is further sequestered to https://doi.org/10.1016/j.ecoenv.2020.110735 Received 4 March 2020; Received in revised form 8 May 2020; Accepted 9 May 2020 ∗ Corresponding author. ∗∗ Corresponding author. E-mail addresses: gitivermabiochem@gmail.com (G. Verma), chakrabartyd@nbri.res.in (D. Chakrabarty). 1 Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India. Ecotoxicology and Environmental Safety 201 (2020) 110735 0147-6513/ © 2020 Elsevier Inc. All rights reserved. T