Comparative Lipidomic Analysis Reveals Heat Stress Responses of Two Soybean Genotypes Differing in Temperature Sensitivity

• Main Authors: Sruthi Narayanan, Zolian S. Zoong-Lwe, Nitant Gandhi, Ruth Welti, Benjamin Fallen, James R. Smith, Sachin Rustgi
• Format: Article
• Language: English
• Published: MDPI AG 2020-04-01
• Series: Plants
• Subjects: soybean; heat stress; lipidomics; lipid metabolic changes; lipid unsaturation; fatty acid desaturase
• Online Access: https://www.mdpi.com/2223-7747/9/4/457

Heat-induced changes in lipidome and their influence on stress adaptation are not well-defined in plants. We investigated if lipid metabolic changes contribute to differences in heat stress responses in a heat-tolerant soybean genotype DS25-1 and a heat-susceptible soybean genotype DT97-4290. Both genotypes were grown at optimal temperatures (OT; 30/20 °C) for 15 days. Subsequently, half of the plants were exposed to heat stress (38/28 °C) for 11 days, and the rest were kept at OT. Leaf samples were collected for lipid and RNA extractions on the 9^th and 11^th days of stress, respectively. We observed a decline in the lipid unsaturation level due to a decrease in the polyunsaturated linolenic acid (18:3) content in DS25-1. When examined under OT conditions, DS25-1 and DT97-4290 showed no significant differences in the expression pattern of the <i>Fatty Acid Desaturase</i> (<i>FAD</i>) <i>2-1A</i>, <i>FAD2-2B</i>, <i>FAD2-2C</i>, <i>FAD3A</i> genes. Under heat stress conditions, substantial reductions in the expression levels of the <i>FAD3A</i> and <i>FAD3B</i> genes, which convert 18:2 lipids to 18:3, were observed in DS25-1. Our results suggest that decrease in levels of lipids containing 18:3 acyl chains under heat stress in DS25-1 is a likely consequence of reduced <i>FAD3A</i> and <i>FAD3B</i> expression, and the decrease in 18:3 contributes to DS25-1′s maintenance of membrane functionality and heat tolerance.