不同柞蚕品种的热应激反应差异及2个热激蛋白基因的表达特征

Difference in Heat Shock Response of Antheraea pernyi Larvae from Different Varieties and Expression Characteristics of Two Heat Shock Protein Genes

野外放养柞蚕经常会受到高温环境胁迫,研究不同柞蚕品种对高温的应激反应和耐受性机制,有利于科学地评价柞蚕种质资源对环境的适应能力。调查5个柞蚕品种或品系5龄幼虫在42℃和45℃胁迫1～4 h后的热应激行为表现、高温胁迫后的恢复能力和胁迫处理后室温饲养48 h的死亡率,结果显示,方山黄和F的耐热性较好、恢复能力较强,高温胁迫后48 h抗大和F的死亡率较低。高温胁迫1 h后分别取2个胁迫试验组5个柞蚕品种5龄幼虫的脂肪体,qRT-PCR检测热激蛋白基因ApHSP70与ApHSP90的表达变化,结果显示:胁迫后不同品种ApHSP70基因的表达量均显著高于对照组(395～1 124倍),以方山黄的胁迫组和对照组表达量最高;42℃胁迫组抗大与9906、45℃胁迫组5204与9906的ApHSP70基因表达量无显著差异(P>0.05),其余均呈极显著差异(P<0.01)。高温胁迫后不同品种ApHSP90基因的表达量也明显高于对照组(26～460倍),仍以方山黄的胁迫组和对照组表达量最高;42℃对照组方山黄与其他品种ApHSP90的表达水平呈显著差异(P<0.05),而42℃方山黄对照组与抗大胁迫组无显著差异(P>0.05);42℃胁迫组5204与方山黄的ApHSP90基因表达水平呈显著差异(P<0.05),45℃胁迫试验组的抗大与F的ApHSP90基因表达水平不存在显著差异(P>0.05),其余均呈极显著差异(P<0.01)。研究结果可为柞蚕种质资源耐高温胁迫能力评价与柞蚕抗逆性新品种选育提供参考。

Tussah silkworm(Antheraea pernyi)raised in open field is often subjected to high temperature environmental stress.Knowledge on stress response and tolerance mechanism of different tussah silkworm varieties to high temperature is beneficial for scientific evaluation on the adaptability of tussah germplasm resources to environment.In this study,heat stress response,recuperability and mortality within 48 h of the 5 th instar tussah larvae from 5 varieties were surveyed under 42 ℃ and 45 ℃ high temperature stress for 1 to 4 h.Results showed that tussah silkworm variety Fangshanhuang and F had better thermostability and recuperability,while Kangda and F had lower mortality than other varieties.Expression profile of ApHSP70 and ApHSP90 genes in fat body of the5 th instar tussah larvae from 5 varieties in two treatment groups after heat stress for 1 h were detected by qRTPCR.The expression level of ApHSP70 in tussah larvae from different varieties after heat stress was significantly higher than that of control group(395 to 1 124 folds).Fangshanhuang had the highest expression level in both heat stress group and control group.The expression level of ApHSP70 showed extremely significant difference between varieties(P<0.01)except for that between Kangda and 9906 in 42 ℃ stress group and that between 5204 and9906 in 45 ℃ stress group(P>0.05).The expression level of ApHSP90 in tussah larvae from different varieties after heat stress was also significantly higher than that of control group(26 to 460 folds).Fangshanhuang had the highest expression level in both heat stress group and control group.In 42 ℃ stress experiment,the expression level of ApHSP90 in Fangshanhuang control group was significantly higher than that of other varieties(P<0.05),but had no significant difference with Kangda in heat stress group(P>0.05).Moreover,the expression level of ApHSP90 showed extreme significant difference between varieties(P<0.01)except for that between 5204 and Fangshanhuang in 42 ℃ stress group and that between F and Kangda in 45 ℃ stress group(P>0.05).These results may provide a reference for evaluating the heat tolerance of tussah germplasm resources and breeding stress resistant tussah varieties.