| Superoxide Dismutase Mimics?SODm?is a small organic compound with homologous peptides synthesized from food grade amino acids as organic ligand and metal ion based on the theory of organic chemistry and biochemistry.A large number of experimental results have shown that SODm applied in the field can promote the growth of crops,increase crop yield and stress resistance.In this study,tomato was treated with different application methods and different application doses of SODm to observe their effects on the physiological characteristics of tomato,and to find the most suitable application mode and application concentration of SODm to tomato.On this basis,the most suitable application method and application concentration of SODm to tomato were selected,and transcriptome sequencing was performed to investigate how SODm regulates the growth of tomato and improves the resistance of tomato from the molecular level.The main research results are as follows:Spraying different concentrations of SODm had no obvious effect on tomato.Spraying high concentrations of SODm not only did not promote the photosynthesis and stress resistance of tomato,but had an effect on the normal growth of tomato.Irrigating different concentrations of SODm significantly promoted the photosynthesis of tomato and increased the antioxidant capacity of tomato.In a comprehensive comparison,7.5 g·L-1 SODm is a suitable application method and application concentration.In order to further study how SODm promotes tomato growth and improves the stress tolerance of tomato by regulating gene expression,the tomato roots were treated with 7.5 g·L-1 SODm for 2 hours and 96 hours for transcriptome sequencing.Compared with the control,64 differentially expressed genes were identified in samples treated with 7.5 g·L-1 SODm for 2 hours,of which 35 were up-regulated genes and 29 were down-regulated genes.341 differentially expressed genes were identified in samples treated with 7.5 g·L-1 SODm for 96 hours,of which 210 were up-regulated genes and 131 were down-regulated genes.Differentially expressed genes identified in samples treated with 7.5 g·L-1 SODm for 2 hours and96 hours involved 13 different pathways,including membrane transport,transcription,global and overview maps,carbohydrate metabolism,amino acid metabolism,biosynthesis of other secondary metabolites,energy metabolism,metabolism of other amino acids,lipid metabolism,metabolism of cofactors and vitamins,glycan biosynthesis and metabolism,nucleotide metabolism and environmental adaptation.The differentially expressed genes identified in samples treated with 7.5 g·L-1 SODm for 96hours also involved six different pathways including transport and catabolism,signal transduction,translation,folding,sorting and degradation,replication and repair,metabolism of terpenoids and polyketides.Enrichment analysis of pathways involved in differentially expressed genes was carried.The differentially expressed genes identified in samples treated with 7.5 g·L-1 SODm for 2 hours were mainly enriched in biosynthesis of secondary metabolites,metabolic pathways and fatty acid metabolism.The differentially expressed genes identified in samples treated with 7.5 g·L-1 SODm for96 hours were mainly enriched in carotenoid biosynthesis,diterpenoid biosynthesis,sulfur metabolism,biosynthesis of secondary metabolites,ABC transporters,isoflavonoid biosynthesis and cysteine and methionine metabolism.The results of the study indicate that SODm mainly regulates various intracellular synthesis and metabolic pathways and participates in related pathways for signal transduction and substance transport in tomato.This study laid a theoretical foundation for elucidating SODm's promotion of plant growth mechanism and discovery of key genes for plant growth. |
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