Molecular Mechanisms Of Visual-olfactory Bimodal Learning In Apis Cerana Cerana

Multimodal perception is the need for animals to recognize the world and make decisions of relevant events in the environment.In this study,transcriptome and proteomics analysis were performed on the visual-olfactory bimodal learning group,visual control group and olfactory control group.By analyzing the differences in transcription level and protein level of the three groups,the biological characteristics of different learning patterns of Apis cerana cerana were revealed.Moreover,according to the results of multi-omics analysis,key regulator of genes,which affecting the visual-olfactory bimodal learning of bees were screened out.Then RNA interference and PER experiment were used to verify whether these genes were involved in the visual-olfactory bimodal learning of bees.1.Through the PER experiment of the Apis cerana cerana,it was proved that the Apis cerana cerana and Apis mellifera could not distinguish the reward stimulus and the nonreward stimulus by color under the condition of intact antennae and bundling,but if the odor stimulus was introduced into the experiment,Apis cerana cerana could distinguish the reward stimulus and the non-reward stimulus by color.The optimal conditions for the vision-olfactory bimodal PER experiment were determined as follows: before the experiment,the bees were hungry for 4h,and the light intensity of the color stimulus was around 3000 LUX.2.By transcriptional sequencing of RNA-seq,297 genes in visual-olfactory bimodal learning group vs visual control group.232 genes in in visual-olfactory bimodal learning group vs olfactory control group,and 119 common different express genes in the two groups.GO and KEGG analysis showed that DEGs were significantly enriched in oxidation-reduction process,oxidoreductase activity and glutamine family amino acid metabolic process,and were mainly take part in peroxisome,protein processing in endoplasmic reticulum and phototransduction – fly pathway in visual-olfactory bimodal learning group vs visual control group.DEGs were significantly enriched in metabolic process,carbohydrate metabolic process and hydrolase activity,hydrolyzing O-glycosyl compounds,and were mainly take part in starch and sucrose metabolism,protein processing in endoplasmic reticulum and ECM-receptor interaction pathway in visualolfactory bimodal learning group vs olfactory control group.3.A total of 5,387 genes were identified by transcriptome.139 genes in visualolfactory bimodal learning group vs visual control group.66 genes in visual-olfactory bimodal learning group vs olfactory control group.There were 48 common DEGs.Through the protein interaction diagram,it was found that ALDH7A1 was the protein with the most interaction relationship,and this gene was mainly involved in the metabolism pathway of glycine,serine and threonine and affected the metabolism of β-alanine,which is the most important neurotransmitter in the brain.Therefore,the ALDH7A1 gene may be involved in the regulation of visual-olfactory dual-mode learning in bees.4.After the injection of si RNA-ALDH7A1,the bimodal learning and memory of Apis cerana cerana decreased significantly,while the learning and memory of single visual or single olfactory did not change significantly.The results of fluorescence in situ hybridization showed that ALDH7A1 was mainly expressed in the mushroom Kenyon cells of Apis cerana cerana.These results suggest that ALDH7A1 is a key gene that affects the bimodal learning of Apis cerana cerana.In order to determine its influence mechanism,after interfering with the expression of ALDH7A1,changes in the expression levels of ALDH7A1-related genes,proteins and the metabolite β-alanine were detected.It was found that the expression levels of ALDH7A1 and RGN genes and proteins were significantly down-regulated,while the expression levels of GAD were not significantly changed,and the levels of β-alanine were significantly increased.After injecting of 1 μg(50 μg/μL)β-alanine in bees’ brain,the effect on the three different learning tasks was consistent with the results after RNAi-ALDH7A1.Therefore,ALDH7A1 may be involved in dual-mode learning and memory with RGN gene,and ALDH7A1 may be involved in bimodal learning and memory by regulating the level of the metabolite β-alanine.