Melatonin and strigolactone mitigate chromium toxicity through modulation of ascorbate-glutathione pathway and gene expression in tomato

Vaseem Raja; Sami Ullah Qadir; Naveen Kumar; Abdulaziz Abdullah Alsahli; Jörg Rinklebe; Parvaiz Ahmad

doi:10.1016/j.plaphy.2023.107872

Melatonin and strigolactone mitigate chromium toxicity through modulation of ascorbate-glutathione pathway and gene expression in tomato

Plant Physiol Biochem. 2023 Aug:201:107872. doi: 10.1016/j.plaphy.2023.107872. Epub 2023 Jul 13.

Authors

Vaseem Raja¹, Sami Ullah Qadir², Naveen Kumar¹, Abdulaziz Abdullah Alsahli³, Jörg Rinklebe⁴, Parvaiz Ahmad⁵

Affiliations

¹ University Centre for Research and Development, Chandigarh University, Gharuan, Mohali, Punjab, 140413, India.
² Department of Environmental Sciences Govt. Degree College for Women, Udhampur, 182101, India.
³ Botany and Microbiology Department, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia.
⁴ University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water and Waste Management, Laboratory of Soil and Groundwater Management, Pauluskirchstraße 7, 42285, Wuppertal, Germany.
⁵ Department of Botany, GDC, Pulwama, 192301, Jammu and Kashmir, India. Electronic address: parvaizbot@yahoo.com.

PMID: 37478726
DOI: 10.1016/j.plaphy.2023.107872

Abstract

Chromium (Cr) is considered one of the most hazardous metal contaminant reducing crop production and putting human health at risk. Phytohormones are known to regulate chromium stress, however, the function of melatonin and strigolactones in Chromium stress tolerance in tomato is rarely investigated. Here we investigated the potential role of melatonin (ML) and strigolactone (SL) on mitigating Chromium toxicity in tomato. With exposure to 300 μM Cr stress a remarkable decline in growth (63.01%), biomass yield (50.25)%, Pigment content (24.32%), photosynthesis, gas exchange and Physico-biochemical attributes of tomato was observed. Cr treatment also resulted in oxidative stress closely associated with higher H₂O₂ generation (215.66%), Lipid peroxidation (50.29%), electrolyte leakage (440.01%) and accumulation of osmolytes like proline and glycine betine. Moreover, Cr toxicity up-regulated the transcriptional expression profiles of antioxidant, stress related and metal transporter genes and down-regulated the genes related to photosynthesis. The application of ML and SL alleviated the Cr induced phytotoxic effects on photosynthetic pigments, gas exchange parameters and restored growth of tomato plants. ML and SL supplementation induced plant defense system via enhanced regulation of antioxidant enzymes, ascorbate and glutathione pool and transcriptional regulation of several genes. The coordinated regulation of antioxidant and glyoxalase systems expressively suppressed the oxidative stress. Hence, ML and SL application might be considered as an effective approach for minimizing Cr uptake and its detrimental effects in tomato plants grown in contaminated soils. The study may also provide new insights into the role of transcriptional regulation in the protection against heavy metal toxicity.

Keywords: Antioxidants. chromium; Gene expression; Melatonin; ROS; Strigolactone.