The Exogenous Application of 24-Epibrassinolide (24-EBL) Increases the Cd and Pb Resilience in Zea mays (L.) by Regulating the Growth and Physiological Mechanism

Zaryab Shafi; Mohammad Shahid; Amal Mohamed AlGarawi; Mohammad Tarique Zeyad; Samy A Marey; Ashraf Atef Hatamleh; Shifa Wang; Udai B Singh

doi:10.1007/s12010-023-04730-4

The Exogenous Application of 24-Epibrassinolide (24-EBL) Increases the Cd and Pb Resilience in Zea mays (L.) by Regulating the Growth and Physiological Mechanism

Appl Biochem Biotechnol. 2023 Oct 4. doi: 10.1007/s12010-023-04730-4. Online ahead of print.

Authors

Zaryab Shafi¹, Mohammad Shahid², Amal Mohamed AlGarawi³, Mohammad Tarique Zeyad⁴, Samy A Marey⁵, Ashraf Atef Hatamleh³, Shifa Wang⁶, Udai B Singh¹

Affiliations

¹ Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-NBAIM, Kushmaur, Mau, U.P, India.
² Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-NBAIM, Kushmaur, Mau, U.P, India. shahidfaiz5@gmail.com.
³ Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, 11451, Riyadh, Saudi Arabia.
⁴ Department of Agricultural Microbiology, Faculty of Agriculture Sciences, Aligarh Muslim University (A.M.U), Aligarh, UP-20202, India.
⁵ King Saud University, 11451, Riyadh, Saudi Arabia.
⁶ School of Electronic and Information Engineering, Chongqing Three Gorges University, Chongqing, 404000, Wanzhou, China.

PMID: 37792177
DOI: 10.1007/s12010-023-04730-4

Abstract

Heavy metals (HMs) at a concentration above the threshold level act as environmental pollutants and very often threaten the agricultural productivity globally. Finding affordable and environmentally sustainable deliverables to address this issue is therefore a top focus. Phytohormones alleviate the HMs-induced toxicity and positively influence the plant growth. Considering the importance of phytohormones, the present study aimed to assess the effect of 24-epibrassinolide (24-EBL; 10 µM) as seed soaking treatment on growth performance of Zea mays (L.) contaminated separately with increasing concentrations (50-400 mg.kg^-1) of lead (Pb) and cadmium (Cd). With increasing metal concentrations, growth and plant biometric criteria were reduced. For instance, Cd at 400 mg.kg^-1 soil reduced the germination efficiency (56%), root (77%) and shoot (69%) dry weight, total chlorophyll (64%), and carotenoid content (45%). Contrarily, both HMs caused increase in stress biomarkers and antioxidant enzymes in seedling. However, exogenous administration of 24-EBL significantly enhanced the growth attributes, photosynthetic pigments, proline, MDA, and antioxidant enzyme activity while reducing the harmful effects of HMs stress on Z. mays. For instance, 24-EBL (10 µM) improved the germination percentage, root biomass, chl a, chl b, total chlorophyll, and carotenoid content by 16, 21, 17, 34, 18, and 15%, respectively, in 50 mg.Pb.kg^-1 soil-treated Z. mays plants. Furthermore, the amounts of proline, MDA, and antioxidant enzymes in foliage of Z. mays were interestingly and dramatically lowered by 24-EBL application. Uptake of metals in plant organs was significantly reduced when 24-EBL was applied to Pb- and Cd-treated Z. mays. The recent findings help us better understand how 24-EBL regulates growth and development of Z. mays as well as how it boosts HMs' resilience, which could increase the possibility of employing 24-EBL to increase Z. mays productivity. Thus, the present findings confirmed the potentiality of pre-soaking the seed in 24-EBL solution that neutralizes the toxic effects of heavy metals in Z. mays plants. Therefore, it is suggested that applying phytohormones including 24-EBL in removal of heavy metal stress in plants is the best possible solution in sustainable agriculture.

Keywords: 24-Epibrassinolide (EBL); Antioxidant enzyme; Cd and Pb toxicity; Growth and physiology; Phytohormones; Zea mays (L.).

Grants and funding

RSPD2023R752/King Saud University