Mycorrhiza improves cold tolerance of Satsuma orange by inducing antioxidant enzyme gene expression

A potted experiment was carried out to study the effect of an arbuscular mycorrhizal fungus (Diversispora versiformis) and like (Piriformospora indica) on antioxidant enzyme defense system Satsuma orange (Citrus sinensis cv. Oita 4) grafted Poncirus trifoliata under favourable temperature (25°C) cold (0°C) for 12 h. Such short-term treatment did not cause any significant change in root fungal colonization spore density soil. Under stress, D. versiformis inoculation activity superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) leaves roots, whereas P. indica significantly increased CAT roots POD only. In addition, two fungi stress relative expression levels PtPOD PtF-SOD leaves, up-regulated PtCu/Zn-SOD also induced PtMn-SOD PtCAT1 leaves. inoculated 4 trees maintained lower hydrogen peroxide malondialdehyde contents temperature, suggesting oxidative damage. Therefore, we concluded that (especially mainly genes, depending species, thus mitigated damage higher resistance plants.