Arbuscular Mycorrhizal Fungi Induced Plant Resistance against Fusarium Wilt in Jasmonate Biosynthesis Defective Mutant and Wild Type of Tomato.

Arbuscular mycorrhizal (AM) fungi can form mutual symbiotic associations with most terrestrial plants and improve the resistance of host plants against pathogens. However, the bioprotection provided by AM fungi can depend on the host-fungus combinations. In this study, we unraveled the effects of pre-inoculation with AM fungus on plant resistance against the hemibiotrophic fungal pathogen in jasmonate (JA) biosynthesis mutant tomato, () and the wild type Castlemart (CM). Results showed that colonization in CM plants significantly decreased the disease index, which was not observed in plants, suggesting that the disease protection of AM fungi was a plant-genotype-specific trait. Inoculation with significantly increased the shoot dry weight of CM plants when infected with , with increased plant P content and net photosynthetic rate. Induced expression of the JA synthesis genes, including allene oxide cyclase gene () and lipoxygenase D gene (), and increased activities of polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL) were recorded in mycorrhizal CM plants infected with , but not in plants. Thus, mycorrhiza-induced resistance (MIR) to fungal pathogen in tomato was highly relevant to the JA signaling pathway.