Methyl Jasmonate Alleviated the Adverse Effects of Cadmium Stress in Pea (Pisum sativum L.): A Nexus of Photosystem II Activity and Dynamics of Redox Balance

Hamid Manzoor; Mehwish; Sherien Bukhat; Sumaira Rasul; Muhammad Ishaq Asif Rehmani; Sibgha Noreen; Habib-Ur-Rehman Athar; Zafar Ullah Zafar; Milan Skalicky; Walid Soufan; Marian Brestic; Muhammad Habib-Ur-Rahman; Chukwuma C Ogbaga; Ayman El Sabagh

doi:10.3389/fpls.2022.860664

Methyl Jasmonate Alleviated the Adverse Effects of Cadmium Stress in Pea (Pisum sativum L.): A Nexus of Photosystem II Activity and Dynamics of Redox Balance

Front Plant Sci. 2022 Mar 24:13:860664. doi: 10.3389/fpls.2022.860664. eCollection 2022.

Authors

Affiliations

¹ Institute of Molecular Biology and Biotechnology, Bahauddin Zakariya University, Multan, Pakistan.
² Department of Agronomy, Ghazi University, Dera Ghazi Khan, Pakistan.
³ Institute of Pure and Applied Biology, Bahauddin Zakariya University, Multan, Pakistan.
⁴ Department of Botany and Plant Physiology, Faculty of Agrobiology, Food, and Natural Resources, Czech University of Life Sciences Prague, Prague, Czechia.
⁵ Plant Production Department, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia.
⁶ Laboratory Slovak University of Agriculture in Nitradisabled, Nitra, Slovakia.
⁷ Crop Science, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Bonn, Germany.
⁸ Department of Biological Sciences, Nile University of Nigeria, Abuja, Nigeria.
⁹ Department of Agronomy, Faculty of Agriculture, Kafrelsheikh University, Kafr El-Shaikh, Egypt.

Abstract

The accumulation of cadmium (Cd) in leaves reduces photosynthetic capacity by degrading photosynthetic pigments, reducing photosystem II activity, and producing reactive oxygen species (ROS). Though it was demonstrated that the application of Methyl Jasmonate (MeJA) induces heavy metal (HM) stress tolerance in plants, its role in adjusting redox balance and photosynthetic machinery is unclear. In this study, the role of MeJA in modulating photosystem II (PSII) activity and antioxidant defense system was investigated to reduce the toxic effects of Cd on the growth of pea (Pisum sativum L.) cultivars. One-week-old seedlings of three pea varieties were subjected to Cd stress (0, 50, 100 μm), and MeJA (0, 1, 5, 10 μm) was applied as a foliar spray for 2 weeks. Cadmium stress reduced the growth of all three pea varieties. Cadmium stress decreased photosynthetic pigments [Chl a (58.15%), Chl b (48.97%), total Chl (51.9%) and carotenoids (44.01%)] and efficiency of photosystem II [Fv/Fm (19.52%) and Y(II; 67.67%)], while it substantially increased Cd accumulation along with an increase in ROS (79.09%) and lipid peroxidation (129.28%). However, such adverse effects of Cd stress varied in different pea varieties. Exogenous application of MeJA increased the activity of a battery of antioxidant enzymes [superoxide dismutase (33.68%), peroxidase (29.75%), and catalase (38.86%)], improved photosynthetic pigments and PSII efficiency. This led to improved growth of pea varieties under Cd stress, such as increased fresh and dry weights of shoots and roots. In addition, improvement in root biomass by MeJA was more significant than that of shoot biomass. Thus, the mitigating effect of MeJA was attributed to its role in cellular redox balance and photosynthetic machinery of pea plants when exposed to Cd stress.

Keywords: antioxidants; cadmium toxicity; methyl jasmonate; oxidative stress; photosystem II.