The Metabolomics Analysis Of Sugarcane In Response Of Oriential Armworm Mythimna Separate Feeding

Sugarcane(Saccharum spp.hybrids.)is the most important sugar crop in China,and it can also be used to make ethanol,so it is also a potential energy crop.The healthy development of sugarcane industry has an important influence on the development of the whole national economy.Becuase of the long growth period and long-term perennial root,sugarcane is easily affected by various pests.So that the sugarcane pest is an important factor which restrict the healthy development of sugarcane industry.Mythirnna separata belongs to Lepidoptera,typically long-range migratory pest,and it is harmful to main grain crops such as corn,rice,and wheat.In sugarcane producing area in our country,the intermittent outbreak of armyworm has brought serious influence to the healthy production of sugarcane.Breeding and utilizing insect-resistant varieties is the most economical and effective method for controlling pests.At present,the research of sugarcane insect resistance mainly focus on the identification of insect resistance of varieties or germplasm,but lack of research on the mechanism of sugarcane insect resistance limits the excavation and utilization of sugarcane insect resistance genes and metabolites.In our study,gene expression and metabolite changes on the metabolic pathways in sugarcane at different time points after armyworm feeding are explored using extensive targeted metabolomics techniques combined with pre-determined transcriptome results.Then,according to the selected metabolites,we do some bioassay test to detect and identify the effect of plant-derived metabolites on insect growth and the synergistic effect with chemical pesticides in order to lay the foundation for the development of green pesticides.The main results of this experiment are as follows:1.Total of 339 metabolites were detected in the metabolomic assay under the conditions of feeding stress,of which 40 differential metabolites were selected in the12 h treatment group and 55 were selected in the 24 h treatment group.According to the classification mainly includes flavonoids,lipids,phenolic acids,amino acids and their derivatives,nucleic acids and derivatives and alkaloids.2.By KEGG annotation analysis of the differential metabolites,it can be found that the differential metabolites are mainly enriched in the pathway of phenylpropane metabolism,flavonoid synthesis,secondary metabolite synthesis,amino acid metabolism,carbohydrate metabolism and so on.3.Combined metabolites with plant defense metabolic pathways revealed that both carbohydrate metabolic pathways,phenylpropanoid metabolic pathways,and nicotine synthetic metabolic pathways all showed up-regulated,while the amino acid content in nitrogen metabolic pathways did not change significantly.At the same time,the content of feruloyl substances closely related to cell wall synthesis in plants increased significantly,and the content of glutathione associated with reactive oxygen species metabolism also showed a significant increase;4.Three different metabolites,6-hydroxyanic acid,p-aminobenzoic acid and chlorogenic acid,were selected from the differential metabolites to carry on the bioassay.It was found that the long-term feeding with chlorogenic acid can cause the death of armyworm larva while feeding with p-aminobenzoic acid can decrease the pupation rate and prolonge the emergence time.5.We found that the mixture of p-aminobenzoic acid with chlorobenzamide have synergistic effect,but the mixture of other substances with insecticides have no obvious synergistic effect.