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利用对氟化物高度敏感的家蚕品种733新和高度耐受性品种T6构建耐氟近等基因系,对回交15代的近等基因系群体从幼虫2龄眠起开始至4龄第3天连续添食200 mg/kg NaF溶液浸渍的桑叶,调查蚕体重要代谢酶类谷胱甘肽硫转移酶(glutathione S-transferase,GST)基因表达和酶活性的变化.解剖获取4龄3d幼虫中肠组织进行双向电泳分析的结果显示,近等基因系群体中耐氟个体中肠的GST表达量比敏感个体明显上调.进一步利用实时荧光定量PCR检测GST基因在耐氟个体与敏感个体中肠、血淋巴、脂肪体和马氏管中的相对表达量,并对5龄1～6d幼虫中肠、血淋巴中的GST酶活力进行测定.结果表明,家蚕对氟化物的抵抗力可能与体内GST酶活力的强弱有关,由于受氟化物刺激的诱导,可能导致GST基因表达水平发生了变化.研究结果为进一步探索家蚕耐氟机制提供了有用信息.“,”In this study,two silkworm varieties named 733Xin (highly sensitive to fluoride) and T6 (highly endurable to fluoride) were used to construct silkworm near-isogenic line (NIL) of the dominant endurance to fluoride.The molting silkworm larvae of the 2nd instar from the 15th back-cross generation of NIL were fed with mulberry leaves soaked in 200 mg/kg NaF solution till day 3 of the 4th instar.The gene expression and emzymatic activity of improtant metabolic enzyme glutathione S-transferase (GST) in silkworm was investigated to explore the mechanism of silkworm resistance to fluoride.Two-dimensional gel electrophoresis (2-DE) detection showed that the expression of GST in midgut of fluoride-resistant individuals was much higher than that in sensitive individuals.We then detected the relative expression level of GST gene in the blood,midgut,fat body,and Malpighian tubule of fluoride-resistant and fluoride-sensitive individuals by real-time quantitative PCR.GST activity in midgut and blood of the 5th instar silkworm larvae from the resistant and sensitive individuals was further measured.The results indicate that the resistance of silkworm to fluoride might be associated with the level of GST activity,which may lead to expressional level change of GST gene.The present results provide useful clues for further investigations on the mechanism of fluoride resistance in silkworm.