The Expression Analysis Of Cold-resistant Genes In The Asian Corn Borer During Diapause

Asian corn borer,Ostrinia furnacalis(Guenee),which is the recurrent pest that damages in maize in our country,overwinters as a fifth instar freeze-tolerant diapausing larvae and belongs to typical facultative diapausing insect.In order to explore low-temperature stress tolerance processes,based on the assessment the the stability reference genes expression of Asian corn borer overwintering larvae and at different insect stages.the expression of selected genes coding for stress related proteins-arginine kinase(AK),glutathione S-transferase(Gst)and triosephosphate isomerase(Tpi)-was assessed by RT-qPCR technology in this study.Then,by the method of RT-qPCR analyze the expression levels of AK,Gst and Tpi from over-wintering larvae and diapause-destined,warm(22?)and cold(5?)acclimated diapausing larvae.The investigation aimed to a better understanding of the molecular adaptation mechanisms to low-temperatrue stress was carried out in Ostrinia furnacalis larvae.The results were as follow:(1)Selecting the suitable reference genes in Ostrinia furnacalis(Guenee).The stability of above four candidate reference genes were 18S rRNA>EF1-a>?-actin>RPS3 from different stages of Ostrinia furnacalis(Guenee);The stability of above four candidate reference genes were ?-actin>EF1-a>18S rRNA>RPS3 from over-wintering larvae of Ostrinia furnacalis(Guenee).18S rRNA and ?-actin can be respectively uesd as a reference gene for different states and diapauese in different months of Ostrinia furnacalis(Guenee)in the experiment of the level of gene expression.(2)Explore diapause-linked stress tolerance processes.The genes expression levels of AK,Gst and Tpi were assessed by RT-qPCR technology of Ostrinia furnacalis duringdiapause-destined,warm(22?)and cold(5?)acclimated diapausing larvae.During the initiation phase of diapause,the abundance of mRNA transcripts of Gst was significantly downregulated,AK and Tpi were unchanged.The expression of only Tpi was downregulated in warm-acclimated larvae;three genes were all upregulated in cold-acclimated larvae.Furthermore,the relative expression of all genes increased gradually throughout the diapause in cold-acclimated larvae.This result indicates that the half-life of mRNAs is prolonged during diapause at low temperature and a gradual accumulation of mRNA transcripts,both diapause programming and temperatures affect the expression of stress-related genes in Ostrinia nubilalis.(3)Understanding the time dynamic of gene expression of AK,Gst and Tpi of overwintering larvae during diapause.Analysing the expression levels of AK,Gst and Tpi were all upregulated,and and the temperature is a negative correlation.Energy metabolism,and antioxidative reaction act in the low-temperature stress process of Ostrinia furnacalis diapause larvae.