Brassinosteroids as promoters of seedling growth and antioxidant activity under heavy metal zinc stress in mung bean (Vigna radiata L.)

Naresh Kumar; Vikas Sharma; Gurpreet Kaur; Charu Lata; Hemant Dasila; Kahkashan Perveen; Faheema Khan; Vijay K Gupta; Mehrun Nisha Khanam

doi:10.3389/fmicb.2023.1259103

Brassinosteroids as promoters of seedling growth and antioxidant activity under heavy metal zinc stress in mung bean (Vigna radiata L.)

Front Microbiol. 2023 Oct 5:14:1259103. doi: 10.3389/fmicb.2023.1259103. eCollection 2023.

Authors

Naresh Kumar^{1

2}, Vikas Sharma³, Gurpreet Kaur⁴, Charu Lata⁵, Hemant Dasila⁶, Kahkashan Perveen⁷, Faheema Khan⁷, Vijay K Gupta², Mehrun Nisha Khanam⁸

Affiliations

¹ Department of Chemistry and Biochemistry, Eternal University, Rajgarh, India.
² Department of Biochemistry, Kurukshetra University, Kurukshetra, India.
³ ICAR-National Dairy Research Institute, Karnal, India.
⁴ ICAR-Central Soil Salinity Research Institute, Karnal, India.
⁵ ICAR- Indian Institute of Wheat and Barley Research, RRS, Shimla, India.
⁶ Department of Microbiology, Eternal University, Rajgarh, India.
⁷ Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia.
⁸ School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea.

Abstract

The escalation of harmful pollutants, including heavy metals, due to industrialization and urbanization has become a global concern. To mitigate the negative impacts of heavy metal stress on germination and early plant development, growth regulators have been employed. This study aimed to evaluate the response of mung bean (Vigna radiata L.) to zinc stress in the presence of brassinosteroids, focusing on seedling growth and antioxidant potential. Mung bean seedlings were treated with three concentrations of 24-epibrassinolide (EBL) (0.1, 0.2, and 0.4 PPM) with or without zinc. Results demonstrated that the application of brassinosteroids, combined with zinc stress, significantly enhanced germination percentage (about 47.06, 63.64, and 120%), speed of germination (about 39.13, 50, and 100%), seedling growth (about 38% in case of treatment combined 0.4 PPM 24-EBL and 1.5 mM ZnSO₄) and seedling vigor index (204% in case of treatment combined 0.4 PPM 24-EBL and 1.5 mM ZnSO₄) compared to zinc-treated seedlings alone after 24 h. The activities of antioxidative enzymes (catalase, ascorbate peroxidase, polyphenol oxidase, and peroxidase) and total soluble protein content decreased, while lipid peroxidation and proline content exhibited a significant increase (p ≤ 0.05) when compared to the control. However, the negative effects induced by heavy metal stress on these parameters were significantly mitigated by EBL application. Notably, the most effective concentration of EBL in overcoming zinc stress was found to be 0.4 PPM. These findings underscore the potential of exogenously applied brassinosteroids as a valuable tool in phytoremediation projects by ameliorating heavy metal stress.

Keywords: EBL; antioxidative enzymes; brassinosteroids; heavy metal; mung bean; zinc.

Grants and funding

The authors declare financial support was received for the research, authorship, and/or publication of this article. The necessary facilities and funding for conducting this research were graciously provided by Kurukshetra University, Kurukshetra, Haryana.