Physiological mechanism of melatonin attenuating to osmotic stress tolerance in soybean seedlings

Mohammad Shah Jahan; Chang Jiang Zhao; Li Bo Shi; Xiu Ren Liang; Dilfuza Jabborova; Jamal Nasar; Xun Bo Zhou

doi:10.3389/fpls.2023.1193666

Physiological mechanism of melatonin attenuating to osmotic stress tolerance in soybean seedlings

Front Plant Sci. 2023 May 27:14:1193666. doi: 10.3389/fpls.2023.1193666. eCollection 2023.

Authors

Mohammad Shah Jahan^{1

2}, Chang Jiang Zhao¹, Li Bo Shi³, Xiu Ren Liang⁴, Dilfuza Jabborova⁵, Jamal Nasar¹, Xun Bo Zhou¹

Affiliations

¹ Guangxi Key Laboratory of Agro-environment and Agro-products Safety, Key Laboratory of Crop Cultivation and Physiology, College of Agriculture, Guangxi University, Guangxi, Nanning, China.
² Department of Horticulture, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh.
³ MAP Division (Shandong) of Sinochem Agriculture Holdings, Jinan, China.
⁴ Guangxi Ecoengineering Vocational and Technical College, Liuzhou, China.
⁵ Laboratory of Medicinal Plants Genetics and Biotechnology, Institute of Genetics and Plant Experimental Biology, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan.

Abstract

Drought is one of the most significant abiotic stress threatening to crop production worldwide. Soybean is a major legume crop with immense economic significance, but its production is highly dependent on optimum rainfall or abundant irrigation. As the global climate changes, it is more important to find solutions to make plants more resilient to drought. The prime aimed of the study is to investigate the effect of melatonin on drought tolerance in soybean and its potential mechanisms. Soybean seedlings were treated with 20% polyethylene glycol 6000 (PEG 6000) and subjected to osmotic stress (14 days) with or without 100 μM melatonin treatment. Our results revealed that melatonin supplementation significantly mitigated PEG-induced growth retardation and increased water absorption ability. Foliar application of melatonin also increased gas exchange and the chlorophyll fluorescence attributes by the mitigation of the osmotic-induced reduction of the reaction activity of photosystems I and II, net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), electron transport activity, and photosynthetic efficiency. In addition, PEG-induced elevated production of reactive oxygen species (ROS) and malondialdehyde (MDA) content were significantly reversed by melatonin treatment. Equally important, melatonin boosted the antioxidant activities of soybean plants. Moreover, osmotic stress substantially increased abscisic acid (ABA) accumulation in roots and leaves, while melatonin-received plant leaves accumulated less ABA but roots content higher ABA. Similarly, melatonin significantly suppressed ABA biosynthesis and signaling gene expression in soybean exposed to drought stress. Furthermore, osmotic stress significantly suppressed plasmalemma (GmPIPs) and tonoplast aquaporin (GmTIPs) genes expression, and their transcript abundance was up-regulated by melatonin co-addition. Taken together, our results indicated that melatonin potentially improves drought tolerance of soybean through the regulation of ABA and aquaporin gene expression, increasing photosynthetic efficiency as well as enhancing water uptake efficiency.

Keywords: ABA metabolism; Aquaporins; climate change; drought; soybean; water use efficiency.

Grants and funding

The authors declare that no financial support was received for the research, authorship, and/or publication of this article.