Interactive effect of drought and cadmium stress on soybean root morphology and gene expression

• Published in: Ecotoxicology and environmental safety Vol. 175; pp. 90 - 101
• Main Authors: Bashir, Waseem, Anwar, Sumera, Zhao, Qiang, Hussain, Iqbal, Xie, Futi
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 15-07-2019
• Subjects: Abiotic stress; Acetates - metabolism; Antioxidants; Cadmium - toxicity; Cd uptake; Cyclopentanes - metabolism; Droughts; Gene Expression Regulation, Plant - drug effects; Genes, Plant; Gibberellins - metabolism; Glycine max (L.) Merr; Glycine max - drug effects; Glycine max - genetics; Glycine max - growth & development; Hydrogen Peroxide - metabolism; Indoleacetic Acids - metabolism; Oxidative Stress - drug effects; Oxidative Stress - genetics; Oxylipins - metabolism; Plant Roots - genetics; Plant Roots - growth & development; Plant Roots - metabolism; qRT-PCR; Antioxidants; Cd uptake; Glycine max (L.) Merr; Abiotic stress; qRT-PCR
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2019.03.042

Recent climatic changes and low water availability due to unpredictable precipitation have reduced the productivity of soybean (Glycine max [L.] Merr.) cultivars. Limited information is available on how drought affects the accumulation and translocation of cadmium (Cd) by affecting soybean root. In this study, we investigated the effect of polyethylene glycol (PEG; 5% and 10%)-induced drought and Cd (0.2 and 0.5 mg L−1) stresses on soybean root morphology, Cd uptake and gene expression; plants not exposed to these stress (0% PEG and 0 mg L−1 Cd) served as a control. The results showed that drought affected roots morphology and Cd uptake. The reduction in root length, root area and root diameter and increase in catalase activity was less prominent in drought tolerant cultivars (Shennong20 and Liaodou32) than in drought sensitive cultivars (Liaodou3 and Liaodou10). Genes involved in abscisic acid (ABA) degradation, gibberellin and salicylic acid biosynthesis, hydrogen peroxide (H2O2) production and Cd transport were up-regulated, while those involved in zeatinriboside (ZR), indole 3-acetic acid (IAA) and methyl jasmonate (MeJA) biosynthesis were down-regulated under Cd and drought stress. Biosynthesis genes of gibberellin (Glyma03G019800.1), IAA (Glyma02G037600), ZR (XM_003550461.3) and MeJA (Glyma11G007600) were expressed to higher levels in drought tolerant cultivars than in drought sensitive cultivars. These genes represent potential candidates for the development of drought and Cd tolerant soybean cultivars.
•Exposure of soybean cultivars to drought and Cd stress induced various changes in root morphology.•Drought stress reduced Cd uptake by roots.•More genes showed differential expression under Cd + drought stress than Cd and PEG alone.•Biosynthesis genes of GA, IAA, ZR and MeJA were highly expressed in drought tolerant cultivars.•These genes represent potential candidates for the development of drought and Cd tolerant soybean cultivars.