| Lygus pratensis is an important agricultural pest in Xinjiang.In recent years,it seriously threatens the sustainable development of the cotton,forestry and fruit industry in Xinjiang because its growing population causes aggravated damages.The diapause of L.pratensis and its development and fecundity after diapause directly affect the population changes in the next year.However,the diapause and regulatory mechanism of diapause are still unclear.This experiment adopts the traditional ecology technology and modern molecular biology technology to study the effect of different temperatures and photoperiods on the morphological characteristics,biological characteristics,and diapause induction and termination of L.pratensis.The most suitable reference genes of quantitative real-time PCR of L.pratensis under different treatments were selected.The diapause-related genes,proteins,and metabolites were analyzed by using multiomics analysis.The main results are summarized as follows:1.The body size,body color,reproductive system development,developmental duration,and preoviposition period of L.pratensis were all affected by temperature and photoperiod.The changes in body color and reproductive system development of L.pratensis were the most significant factors that could be used as potential research indicators for diapause discrimination of L.pratensis.Under the conditions of 20℃,photoperiod had a significant effect on the developmental duration of the first instar nymphs,the preoviposition period of adults,and the survival rate of the first instar nymphs.Under the conditions of 9L:15D and 15L:9D photoperiod,the developmental duration of the 1st instar nymphs was 7.61 d and 6.87 d,and the preoviposition period of adults was 12.51 d and 10.41 d,respectively.With the prolongation of photoperiod,the developmental duration of 1st instar nymphs and the pre-oviposition period of adults were gradually shortened.The survival rate of the 1st instar nymph was the highest under the photoperiod 15L: 9D,which was 95.83%.2.The induction of the diapause in L.pratensis was significantly influenced by temperature and photoperiod.Adults did not lay eggs at 12℃ but started to lay eggs at 16℃,and the number of eggs increased with the increase of temperature or the prolongation of photoperiod.The diapause rate of adults reared under short photoperiod 9L:15D and 16℃ was the highest,reaching90.7%.The temperature had no significant effect on the rate of diapause termination.However,the time of diapause termination was significantly increased while the temperature increased.Photoperiod has a significant effect on the rate of diapause termination of L.pratensis,and longer photoperiod is beneficial to diapause termination.In addition,while low-temperature treatment is not a necessity for the termination of diapause,it can shorten the time of diapause termination.3.The number of differentially expressed genes between diapause adults and non-diapause adults was 1203,among which 790 genes were up-regulated and 413 genes were down-regulated.KEGG enrichment analysis showed that the differentially expressed genes were mainly enriched in carbohydrate metabolism,lipid metabolism,signal transduction,immune system,and other pathways.The differentially expressed genes related to diapause,such as JHAMT,JHEH,FAS,UGT,and GK,were significantly up-regulated in the diapause group,which may be important genes involved in the diapause regulation of L.pratensis.7 differentially expressed genes were selected and verified by real-time PCR.The results of q RT-PCR were consistent with the results of transcriptome sequencing,indicating the reliability of transcriptome sequencing.The results of reference gene screening showed that RPL19,EF,AK,RPL32,and 18 S were the most stable reference genes in different tissues,temperature,developmental stage,adult culture days,and diapause status,respectively.4.A total of 723 proteins were identified by proteomic analysis,with 148 differentially expressed proteins,68 significantly up-regulated proteins,and 78 significantly down-regulated proteins.A total of 117 differential proteins were annotated in the GO database in the biological process category,and 283 items were enriched.The main processes included the organic carbon compound metabolism process,organic carbon compound biosynthesis process,and small molecule metabolism process.73 differentially expressed proteins were annotated by KEGG,and a total of 58 pathways were enriched,among which 15 pathways were significantly enriched,mainly including cystine and methionine metabolism,ribosome,citric acid cycle,carbon metabolism,glyoxylate,and dicarboxylic acid metabolism.Oxidative phosphorylation,citric acid cycle,ribosomal protein,and heat shock protein,may play a role in the changes in energy metabolism,the development arrest of the endoreproductive system,and the enhancement of stress resistance in the diapause of L.pratensis.5.In positive ion mode,672 metabolites were detected by metabolomics,among which 175 metabolites were significantly different between the two groups;69 metabolites were significantly up-regulated;and 106 metabolites were significantly down-regulated.285 metabolites were detected in the negative ion mode,in which 60 metabolites were significantly different between the two groups,26 metabolites were significantly up-regulated and 34 metabolites were significantly down-regulated.KEGG enrichment analysis was performed on the differential metabolites.In negative ion mode,the differential metabolites were enriched into 23 pathways.In the positive ion mode,the differential metabolites were enriched to 15 pathways.Lipid metabolism and amino acid metabolism were closely related to the diapause of L.pratensis because both of them had highest number of enriched differential metabolites.6.KEGG database was used to integrate and analyze the transcriptome,proteome,and metabolome data.In negative ion mode,50 pathways were enriched,among which 17 pathways were significantly enriched.In positive ion mode,46 pathways were enriched,including 11significantly-enriched pathways.Results from both sole and combined analyses of transcriptome,proteome,and metabolomics showed that diapause was strongly correlated with pathways that were amino acid metabolism,lipid metabolism,and ribosome. |
PDF Full Text Request