Effects Of Short-term Heat Stress On Different Developmental Stages And Heat Shock Protein 70 Gene Expression Of Callosobruchus Chinensis L.

Callosobruchus chinensis L.,harmful to legumes like mung bean,cowpeas,red beans and so on,is a kind of worldwide storage pest.To illustrate the effect mechanism of temperature on C.chinensis,the temperature selectivity of C.chinensis was measured by temperature gradient,the influence of short-term heat stress on different developmental stages had explored,and relative expression of Cc Hsp70 on short-term heat stress had determinated.The main findings are as follows:1.The temperature selectivity of C.chinensis at 4 initial temperatures was measured by a temperature gradient.The result shows that when the initial temperature is 27℃,the C.chinensis tends to a high temperature region,and when the initial temperature is greater than 39℃,it tends to a low temperature region.The high temperature of 45℃ has obvious repellent effect on C.chinensis.The lower selection temperature limits of females and males are close to 30.2℃ and 29.8℃,while the upper selection temperature females are higher than males,which is 38.2℃ and 27.0℃ respectively.2.Short-term high-temperature treatment of C.chinensis with different states under 6 temperature conditions for 3 h.The result shows that the hatching rate of eggs,pupation rate of larvae and the eclosion rate of pupae significantly decreased with exposure to higher temperatures,but exposure to higher temperatures had no significant effect on the subsequent development of eggs and larvae.Larvae were more heat tolerant than pupae having a pupation rate of > 90% after short-term heat stress,but pupae also had a relatively high eclosion rate after exposure to 45℃.However,adults that emerged from pupae exposed to 45℃ had a significantly shortened life span and reduced egg production.There were gender differences in the heat stress tolerance of eggs,larvae and adults and short-term heat stress also had a significant effect on fecundity.Average egg production was 32.30 after exposure to 45℃,significantly lower than that of the control.3.Taking male and female C.chinensis treated with 6 kinds of high temperature for 3 h as the research object.m RNA expression of 8 candidate reference genes(β-actin,α-tubulin,EF1-α,GAPDH,Hsc70,AK,rsp L-40 and β-tubulin)has been detected by quantitative real-time PCR(q RT-PCR).Use ge Norm,Norm Finder and Best Keeper to calculate expression stability of each candidate reference genes.The result shows that the best reference gene on high temperature treatment is β-tubulin.4.Using β-tubulin as the internal reference gene,q RT-PCR analysis was performed on the Hsp70 gene of male and female C.chinensis treated with 6 kinds of temperature for 1 h and 3 h.The relative expression increased significantly at 1h,and decreased after the treatment time was extended to 3 h.After 1h of short-term high temperature,the expression level of Cc Hsp70 in males was the largest at 42℃,which was 25.94 that of the control,and the expression level of female was maximum at 45℃,which was 27.59 times that of the control.After 3 h short-term high temperature treatment,the relative expression level was only 3.19 times that of the control,and it was not significantly different from the control and other treatment groups.