球孢白僵菌侵染对家蚕抗氧化水平的影响  

Effects on Antioxidant Levelsof Silkworm Larvae Infected with Beauveria bassiana

作　　者：王树昌[1] 赫荣帆[2,3] 陆敏泉 黄华平[1] 王娜玉[4] 郭锡杰[2,3] 耿涛 

机构地区：[1]中国热带农业科学院环境与植物保护研究所,海南海口571101 [2]江苏科技大学,江苏镇江212018 [3]中国农业科学院蚕业研究所,江苏镇江212018 [4]海南大学,海南海口570228

出　　处：《热带作物学报》2017年第11期2136-2144,共9页Chinese Journal of Tropical Crops

基　　金：国家自然科学基金项目(No.31272498);中央级公益性科研院所基本科研业务费专项(No.1630042016001);现代农业产业技术体系建设专项(No.CARS-18)

摘　　要：球孢白僵菌(Beauveria bassiana)是一种广谱性、强致病性的病原真菌,然而其致病机制尚不明确,进一步阐释球孢白僵菌尤其是球孢白僵菌毒素的致病机制,对生防应用和病害防控具有重要意义。本研究检测了家蚕幼虫自然感染球孢白僵菌和注射球孢白僵菌毒素以及家蚕细胞添加毒素后,幼虫存活率、家蚕组织和细胞的总抗氧化活力、SOD和CAT酶活性及相关基因表达水平的变化。结果表明,家蚕2龄幼虫感染白僵菌后期(33~48 h),5龄幼虫感染球孢白僵菌后期(48~72 h),5龄幼虫和Bm N细胞注射(添加)球孢白僵菌毒素24 h后,家蚕血淋巴、脂肪体、中肠和马氏管组织、Bm N细胞总抗氧化活力、SOD和CAT酶活性显著降低;脂肪体、中肠、马氏管组织和Bm N细胞中Bmsod和Bmcat基因表达水平在感染后期和添毒后显著下调表达;球孢白僵菌毒素能够诱导家蚕Bm N细胞发生凝集反应并最终凋亡崩解;家蚕幼虫添加外源SOD和CAT等抗氧化剂后,能显著提高家蚕的存活时间。以上结果说明,球孢白僵菌侵染家蚕后,可能通过分泌毒素攻击脂肪体、中肠和马氏管细胞,下调Bmsod和Bmcat基因的表达,降低机体的总抗氧化能力,破坏家蚕的氧化还原平衡,损伤组织器官功能并最终导致家蚕死亡;同时破坏家蚕免疫系统,获得免疫逃逸,以利于菌丝生长、繁殖。Beauveria bassiana, a broad-sp ectrum entomopathogenic fungi with the strong pathogenicity. However,the pathogenic mechanism of B. bassiana was still need to be specifyied the pathogenic mechanism of B. bassiana especially the Beauveria toxins have the important significance for the study on bio-control and disease resistance.In this paper, the total antioxidant activity, SOD（ Superoxide dismutase） activity, CAT（ Catalase） activity and expression levels of Bmsod and Bmcat genes in hemolymph, midgut, fat body and malpighian tubule of silkworm larvae infected with B. bassiana and injected with Beauveria toxins were examined. In addition, the effects of SOD, CAT and Beauveria toxins on the survival rates of silkworm larvae infected with B. bassiana were also examined. Further more, cellular injury of Bm N caused by Beauveria toxins were detected. The results showed that total antioxidant activity, SOD activity, CAT activity and expression levels of antioxidant genes（Bmsod and Bmcat）in 2 instar silkworm larvae（especially from 33 hours to 48 hours post infection with B. bassiana）, in midgut, fat body and malpighian tubule of 5 instar silkworm larvae（ especially from 48 hours to 72 hours post infection with B.bassiana and 48 hours after injected with Beauveria toxins）, and in Bm N cells（ 24 hours after injected with Beauveria toxins） reduced. In addition, Beauveria toxins could induce the agglutination of Bm N cells and finally encourage apoptosis and disintegration. Furthermore, the exogenous antioxidants（ SOD and CAT） could relieve the damage caused by Beauveria toxins. The results above indicated that B. bassiana might secrete toxins, which would attack the fat body, midgut and malpighian tubules of silkworm and down-regulate the expression levels of Bmsod and Bmcat genes, decreased the total antioxidant capacity and disrupt the balance of antioxidant system,which causing function injury of silkworm tissue or organ and lead to the death eventually. Besides, Beauveria toxins might destruct

关 键 词：球孢白僵菌 家蚕 真菌毒素 SOD CAT 

分 类 号：S884[农业科学—特种经济动物饲养]