Ethylene mitigates waterlogging stress by regulating glutathione biosynthesis-related transcripts in soybeans

Waterlogging stress is a restrictive factors in soybean productivity worldwide. Plants utilize various physio-chemical changes to mitigate waterlogging stress. In current study, the regulatory roles of seven kinds of plant growth regulators, including abscisic acid (ABA), ethylene (ethephon, ETP), gibberellins (GA4), indole-3-acetic acid (IAA), kinetine (KT), jasmonic acid (JA) and salicylic acid (SA), were determined for soybeans under waterlogging conditions. Based on the results, the donor source of ethylene was selected and its role was further examined regarding physiochemical alteration and glutathione biosynthesis-related transcripts through application of exogenous ETP. ETP application mitigated waterlogging stress and significantly improved the efficiency of photosynthesis and increased bioactive GA4 contents compared to that of untreated plants. Element and amino acid contents among the treatments were significantly different. Total elements and amino acid contents were increased in 100 μM ETP-treated soybean plants. ETP application induced adventitious root initiation, improved root surface area, and significantly increased glutathione transferases expression and glutathione relative to that of non-ETP treated soybean plants. Finally, 100 μM-ETP application induced up-regulated protein content and glutathione s-transferase DHAR2 as compared to that of soybeans under waterlogging-conditions only. ETP could induce various biochemical and transcriptional modulations that strengthen plant growth and mitigate waterlogging stress. Highlight Ethylene application to soybean plants after waterlogging up-regulates glutathione transferase genes. Higher glutathione activity, as well as increased glutathione s-transferase DHAR2 protein content was induced to scavenge reactive oxygen species.