Early induction of Fe-SOD gene expression is involved in tolerance to Mn toxicity in perennial ryegrass.
Manganese (Mn) toxicity limits plant growth in acid soils. Although Mn toxicity induces oxidative stress, the role of superoxide dismutase (SOD, EC.1.15.1.1) isoforms in conferring Mn tolerance remains unclear. Seedlings of ryegrass cultivars Nui (Mn-sensitive) and Kingston (Mn-tolerant) were hydroponically grown at 2.4 (optimal) or 750 μM Mn (toxic) concentration, and harvested from 2 to 48 h. Kingston showed higher shoot Mn than Nui at 2.4 μM Mn. At toxic supply, shoot Mn concentration steadily increased in both cultivars, with Kingston having the highest accumulation at 48 h. An early (2 h) increase in lipid peroxidation under Mn excess occurred, but it returned (after 6 h) to the basal level in Kingston only. Kingston exhibited higher SOD activity than Nui, and that difference increased due to toxic Mn. In general, Mn-induced gene expression of Mn- and Cu/Zn-SOD isoforms was higher in Nui than Kingston. Nevertheless, under Mn excess, we found a greater Fe-SOD up-regulation (up to 5-fold) in Kingston compared to Nui. Thus, Fe-SOD induction in Kingston might explain, at least partly, its high tolerance to Mn toxicity. This is the first evidence that Mn toxicity causes differential gene expression of SOD isoforms in ryegrass cultivars in the short-term.
Center of Plant-Soil Interaction and Natural Resources Biotechnology, Scientific and Technological Bioresource Nucleus (BIOREN-UFRO), Universidad de La Frontera, Avenida Francisco Salazar 01145, P.O. Box 54-D, Temuco, Chile. Electronic address: alejandra.ribera@ufrontera.cl.
Alejandra
A
Ribera-Fonseca
Claudio
C
Inostroza-Blancheteau
Paula
P
Cartes
Zed
Z
Rengel
M L
ML
Mora
D000222:Adaptation, Physiological / Q000235:genetics*; D015870:Gene Expression / Q000187:drug effects; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D015227:Lipid Peroxidation; D008129:Lolium / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D008345:Manganese / Q000009:adverse effects* / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018520:Plant Shoots / Q000378:metabolism; D020033:Protein Isoforms; D036226:Seedlings; D013045:Species Specificity; D013482:Superoxide Dismutase / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation
D010940:Plant Proteins; D020033:Protein Isoforms; D008345:Manganese; D013482:Superoxide Dismutase
Cu/Zn-SOD; Fe-SOD; Gene expression; Manganese tolerance; Manganese toxicity; Mn-SOD; Oxidative stress; Ryegrass; Superoxide dismutase isoforms; copper/zinc superoxide dismutase; iron superoxide dismutase; manganese superoxide dismutase; qRT-PCR; quantitative real-time polymerase chain reaction