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Ali Khadivi

Ali Khadivi

Academic rank: Professor
ORCID: https://orcid.org/0000-0001-6354-445X
Education: PhD.
ScopusId: 43661256800
Faculty: Agriculture and Environment
Address: Arak University
Phone: 086-32623022

Research

Title
Physiological and molecular mechanisms underlying salicylic acid-mitigated mercury toxicity in lemon balm (Melissa officinalis L.)
Type
JournalPaper
Keywords
Chlorophyll synthase Lipid peroxidation Mercury Phenolics Salicylic acid
Year
2019
Journal Ecotoxicology and Environmental Safety
DOI
Researchers FATEMEH safari ، Morteza Akramian torogh tey ، Hossein Salehi arjmand ، Ali Khadivi

Abstract

Mercury (Hg) is one of the most toxic heavy metals with strong negative effects on the plant growth and functions. Salicylic acid (SA) is an important signaling molecule which confers tolerance to metal toxicities but little is known about the mechanisms of SA-mediated alleviation of Hg stress. Here, physiochemical and molecular responses of Hg-stressed lemon balm (Melissa officinalis L.) to exogenous SA were investigated to reveal SA-induced tolerance mechanisms. The CHLG gene of lemon balm which encodes chlorophyll synthase was also partly isolated and sequenced for the first time. Hg stress markedly decreased growth, relative water content (RWC) and photosynthetic pigments of the plant. However, exogenous SA significantly mitigated the toxic effects of mercury on the growth and RWC and enabled plant to maintain chlorophylls to the similar levels of unstressed plants. Hg-induced oxidative damage was also reduced following treatment with SA and treated plants showed the lower extent of lipid peroxidation which was accompanied with the higher free proline and phenolics contents and elevation of the antioxidant capacity as evidenced by DPPH radical scavenging and FRAP assays. Moreover, SA treatment resulted in up-regulation of CHLG and phenylalanine ammonia-lyase (PAL) genes as key components of chlorophyll and phenylpropanoid routes, respectively. Our results collectively indicate the ameliorative effects of exogenous SA in mercury toxicity through coordinated alternations in plant metabolic processes which provide insights to better understand mechanisms of Hg tolerance in lemon balm plant.