Diversity And Function Of Gut Bacterial Symbions Of Spodoptera Litura

The Spodoptera litura is worldwide distribution pest, main endanger to 109 families of plants,such as cruciferae cabbage, green vegetables, cabbage, radish, bean black-eyed peas, green beans, soybeans, peanuts, green beans, amaranthaceae of amaranth, alternanthera grass, achyranthes, polygonaceae buckwheat and interlock sorrel smartweed, solanaceae, peppers, eggplant, tomatoes, and tobacco, compositae, such as sunflower, chrysanthemum and so on. The moth feeding wide, more than a year occurred generation, and the stronger resistance to pesticides, so difficulty to control. Insect gut bacteria play important role in host feeding, digestion, immune and growth. In this paper we use pure culture of microorganisms combined with modern molecular biology techniques, we examined the diversity of the S. litura gut microbiota.hope to expound the diversity of the S. litura gut bacteria and the relationship between the diets, analyses the reason of the S. litura widespread diets, providing theoretical basis for prevention and treatment of the S. litura.The main results were as follows:1. Diversity of microbiota in the S. litura gutBased on the methods of 16S rRNA sequencing, pure culture of microorganisms, metagenome sequencing, denaturing gradient gel electrophoresis(DGGE) and real-time fluorescent quantitative PCR(real-time PCR detecting policy system qPCR), we examined the diversity of the S. litura gut microbiota. The result suggest that the Proteobacteria is the most highest abundant bacteria in two varieties SI litura midgut of Tar and Art. metagenomic sequencing showed that at the phylum level, little difference between the two bacterial strains, are Proteobacteria and Firmicutes. The Tar strains of S. litura intestinal bacteria deformation bacteria abundance was 86% and the abundance of Firmicutes was 4%; Art strains of S. litura intestinal bacteria deformation bacteria abundance was 80%, Firmicutes abundance was 5%. In order classification of two strains of intestinal bacterial diversity of great changes, Tar strains mainly by the Enterobacteriales (83.67%) and lactobacillales (2.3%); Art lines is mainly composed of intestinal bacillus and Pseudomonas bacteria pseudomonadales (31.95) enterobacteriales (26.9%). At the family level, tar lines mainly by Enterobacteriaceae (83.7%) and Enterococcaceae (1.5%); Art lines is mainly composed of Pseudomonadaceae (31.5%) and Enterobacteriaceae (26.9%). Tar strains compared with Art lines in pseudomonadaceae identifying from their abundance increased significantly, and sharp decline in Enterobacteriaceae abundance. The results showed that feeding on different food change S. litura intestinal bacteria diversity.2. Metagenomics sequencing of S. litura gut bacteriaThe results of metagenome sequencing shows that the S. litura intestinal bacteria coding cellulose degradation enzyme, xylanase and pectinase. CAZymes family analysis found that the S. litura intestinal bacteria involved 2465 encoding gene members of the family of plant cell wall polysaccharides enzyme degradation process.has more glycoside hydrolase glycoside hydrolase(GH) than the DBM, suggests that the polytrophic insect gut bacteria have stronger indican degradation function.we also found that the S. litura gut bacteria can participate in the synthesis of a large number of essential amino acids and non-essential amino acids.indicates that the S. litura gut bacteria may play an important role in food digestion host nutrition.in addition, we discovered the complete aerobe pathway that degrades catechol in the S. litura gut bacteria metagenome, suggests that the S. litura gut bacteria can help host degradation of toxic substances, response to plant defense system against insects.3. Contribution of gut bacterial symbionts to the feeding of S. lituraS. litura feeding cabbage leaf which use antibiotics soaking 24 h and 48 h, measured five indicators of nutrition of the S. litura (the relative growth rate, relative consumption rate, food utilization rate, food conversion rate, approximate rate), the results shows that compared with the control group, treatment group were changed significantly. The relative growth rate, relative take food intake, food utilization of antibiotic treatment have occurred significant reduction within 24 h. Import the Enterobacter and intestinal bacteria after antibiotic treatment, all intestinal bacteria found that the relative growth rate, food conversion rate, food utilization of the S. litura which import the Enterobacter and intestinal bacteria were significantly increased.results showed that antibiotic treatment clear the intestinal bacteria of S. litura, affecting the digestive ability of the host, has a significant effect to the nutrition index of S. litura. import the bacteria, the function of intestinal bacteria tend to restore, suggests that the S. litura gut bacteria contribution to the host’s feeding. The S. litura is one of the most destructive pests attacking crops in the world, this is the first report of high-throughput DNA sequencing of the entire microbiota of S. litura.using metagenome sequencing analysis the intestinal bacteria of S. litura contribution to food digestion, nutrition and metabolic detoxification.our studies provide insights into the mechanism of S. litura herbivory.