Heat Stress-Induced Lipid Alterations in Peanut

Peanut (Arachis hypogaea) is a globally important crop cultivated for human consumption and for the production of seed oil. As anthropogenic climate change continues to challenge global crop production with extreme environmental conditions such as high temperatures, the development of heat-tolerant varieties is crucial to meet peanut production demands. At the cellular level, one of the fundamental causes of yield loss at high temperatures (HT) is membrane damage. This work reports the investigations on a subset of a peanut recombinant inbred line population demonstrating that the membrane lipid remodeling occurring at HT is consistent with homeoviscous adaptation to maintain membrane fluidity. Findings indicate that a major alteration in the peanut leaf lipidome at HT is the reduction in the unsaturation levels, primarily through reductions of 18:3 fatty acid chains, of the plastidic and extra-plastidic diacyl membrane lipids. In contrast, levels of 18:3-containing triacylglycerols (TGs) increased at HT, consistent with a role for TGs in sequestering fatty acids when membrane lipids undergo remodeling during plant stress. Polyunsaturated acyl chains from membrane diacyl lipids are also sequestered as sterol esters (SEs), indicating a role for SEs in HT adaptation. The removal of 18:3 acyl chains from the membrane lipids decreases the availability of susceptible molecules for oxidation thereby minimizing oxidative damage in membranes. Taken together, these results suggest that the transfer of polyunsaturated acyl chains, specifically 18:3, from membrane diacyl lipids to TGs and SEs is a key feature of lipid remodeling for HT adaptation. These findings contribute to the ongoing efforts in understanding heat-tolerance mechanisms which are vital for developing heat-tolerant peanut varieties