Transcriptome Study On Diapause Initiation Of The Bivoltine Silkworm,Bombyx Mori

Respiratory oxygen consumption of diapausing eggs of bivoltine silkworm gradually increased before the initiation of diapause(from Oh to 24h after oviposition),and decreased rapidly during the initiation of diapause(from 24h to 72h after oviposition).During the process of preventing initiation of diapause by the constant HCl-treatment,the respiratory oxygen consumption continues to increase,but its molecular mechanism is unclear.This article compares the differences of transcriptome between the diapausing eggs and HC1 treated eggs.It is focused on the analysis of the differences in the transcription level of biological oxidation-related genes.The result is as follows.1.Transcriptome sequencing analysis in diapause initiation of the bivoltine silkworm.The number of genes whose transcription levels were up-regulated and down-regulated in diapausing eggs continued to increase from Oh to 72h after oviposition,and the constant HC1-treatment increased the number of genes up-regulated and down-regulated at the transcription level further.It can be seen that the number of differentially expressed genes has not decreased in diapause inintiation.When the constant HCl-treatment prevents diapause,the number of differentially expressed genes increases further.2.Differentially expressed genes related to biological oxidation in diapause initiation of the bivoltine silkworm.Along with diapause initiation(from 24h to 72h after oviposition),there are 11 of the genes related to biological oxidationin in diapausing eggs of the bivoltine silkworm have up-regulated transcription levels and 6 have down-regulated transcription levels;The constant HCl-treatment prevented initiation of diapause and reversed the change of the transcription level of the 3 genes of the above genes3.Differentially expressed genes related to NAD+ metabolismin diapause initiation of the bivoltine silkworm.Along with diapause(from 24h to 72h after oviposition),the transcriptional levels of genes named NAD+metabolism named NAD kinase 2,NAD kinase X2,poly(ADP-ribose)polymerase and NAD-dependent deacetylase sirtuin2 in diapausing eggs were significantly down-regulated.The constant HCl-treatment prevents initiation of diapause and reverses the downward trend of transcription level of NAD-dependent deacetylase sirtuin2.4.Leader genes related to diapause initiation of the bivoltine silkworm.In diapausing eggs of bivoltine silkworm,the transcription level of gene named malate dehydrogenase X1,ATP synthase F0,cytochrome c oxidase subunit 6A,glycerol-3-phosphate dehydrogenase,aldehyde and ketone reductase(AKR2E4 X1)and NAD-dependent deacetylase sirtuin2 is consistent with the change trend of respiratory oxygen consumption.The constant HCl-treatment prevents initiation of diapause and reverses the transcription levels of malate dehydrogenase X1,cytochrome c oxidase subunit 6A5 glycerol-3-phosphate dehydro genase and NAD-dependent deacetylase sirtuin2.Among them,the transcription levels of malate dehydrogenase X1 and glycerol-3-phosphate dehydrogenase changed significantly as early as 18h after oviposition,while the level of transcription of cytochrome c oxidase subunit 6A and NAD-dependent deacetylase sirtuin2 did not change significantly until 30 hours after oviposition.The transcript level of malate dehydrogenase X1 changed more than that of glycerol-3-phosphate dehydrogenase.In addition,the change in the transcription level of gene named malate dehydrogenase X1 was also verified by Real-time PCR.It can be seen that the gene named malate dehydrogenase X1 is the leading gene for diapause in the silkworm.