转基因棉种植对土壤水解酶活性的影响

转Bt基因棉和转Bt＋cpTI基因棉种植面积不断扩大,它们种植后杀虫晶体蛋白在土壤中的残留特性及对土壤水解酶活性的影响是环境风险评价的重要组成部分,本文采用盆栽实验的方法对此进行了初步研究。结果表明,转基因棉出苗后生长到30天时可向土壤中释放Bt杀虫晶体蛋白,而双抗棉种植时CpTI杀虫晶体蛋白的释放量与品种有关;转基因棉出苗后30天时,与等价基因系非转基因棉（各对照）相比,转Bt基因棉（“中30”）和双抗棉A（转Bt＋CpTI棉“中41”）的种植并未使脲酶、蛋白酶和磷酸单脂酶活性发生显著变化,而双抗棉B（转Bt＋CpTI棉“双抗321”）的种植使土壤磷酸单脂酶活性显著下降。从杀虫晶体蛋白的释放和对酶活性的影响来看,双抗棉A的种植对土壤的生物活性扰动更小。     

我国转基因Bt抗虫棉的进展分析与生态风险评估

从源头创新、基因转移技术、新品种选育与推广、专利分析四个方面探讨了我国转基因Bt抗虫棉的重大进展。且从靶标昆虫与非目标昆虫两个方面重点对转基因的生态风险进行了综合评价,并根据国内外的研究趋势,提出了加速我国转基因棉研究的对策。     

Does Bt rice pose risks to non‐target arthropods? Results of a meta‐analysis in China

Transgenic Bt rice expressing the insecticidal proteins derived from Bacillus thuringiensis Berliner (Bt) has been developed since 1989. Their ecological risks towards non‐target organisms have been investigated; however, these studies were conducted individually, yielding uncertainty regarding potential agroecological risks associated with large‐scale deployment of Bt rice lines. Here, we developed a meta‐analysis of the existing literature to synthesize current knowledge of the impacts of Bt rice on functional arthropod guilds, including herbivores, predators, parasitoids and detritivores in laboratory and field studies. Laboratory results indicate Bt rice did not influence survival rate and developmental duration of herbivores, although exposure to Bt rice led to reduced egg laying, which correctly predicted their reduced abundance in Bt rice agroecosystems. Similarly, consuming prey exposed to Bt protein did not influence survival, development or fecundity of predators, indicating constant abundances of predators in Bt rice fields. Compared to control agroecosystems, parasitoid populations decreased slightly in Bt rice cropping systems, while detritivores increased. We draw two inferences. One, laboratory studies of Bt rice showing effects on ecological functional groups are mainly either consistent with or more conservative than results of field studies, and two, Bt rice will pose negligible risks to the non‐target functional guilds in future large‐scale Bt rice agroecosystems in China.     

田间转Bt基因水稻上稻飞虱卵量、孵化率及天敌作用

为了评估转基因水稻释放后对非靶标害虫及其天敌的影响, 本研究在浙江大学实验农场和中国水稻研究所实验农场2008和2009年连续两年监测了转Bt基因水稻对田间稻飞虱着卵量、卵孵化率、卵被捕食率、卵被寄生率和卵死亡率的影响。结果表明: 两年2个调查地点3个水稻品系（克螟稻1、克螟稻2和秀水11）上的稻飞虱平均每分蘖着卵量、卵孵化率、卵被捕食率和卵被寄生率的趋势基本一致, 而且田间3个水稻品系上稻飞虱卵量的高峰期均持续2周左右; 但是两年2个调查地点3个水稻品系上稻飞虱卵死亡率则没有一致的趋势。此外, 总体上3个水稻品系上稻飞虱平均每分蘖着卵量、卵孵化率、卵被捕食率、卵被寄生率和卵死亡率差异均不显著（P>0.05）。因此, 稻田中转Bt基因水稻对稻飞虱卵没有显著的影响。     

植物的抗螨机理

植食性螨类分布广泛,危害多种寄主植物.本文从3个方面介绍了植物的抗螨机理:植物形态如叶型、叶色主要影响螨类的取食产卵位点和营养物质的获取;植物组织结构如叶厚、蜡质、茸毛、气孔等决定螨能否顺利利用口针取食到植物的汁液,而虫菌穴则作用于捕食螨和植食性螨的相互关系,从而达到保护植物的目的;植物理化性质如叶鲜重、生长速度、生育...     

Cadherin AdCad1 in Alphitobius diaperinus larvae is a receptor of Cry3Bb toxin from Bacillus thuringiensis

Bacillus thuringiensis (Bt) Cry proteins are used as components of biopesticides or expressed in transgenic crops to control diverse insect pests worldwide. These Cry toxins bind to receptors on the midgut brush border membrane and kill enterocytes culminating in larval mortality. Cadherin proteins have been identified as Cry toxin receptors in diverse lepidopteran, coleopteran, and dipteran species. In the present work we report a 185 kDa cadherin (AdCad1) from larvae of the lesser mealworm (Alphitobius diaperinus) larvae as the first identified receptor for Cry3Bb toxin. The AdCad1 protein contains typical structural components for Cry toxin receptor cadherins, including nine cadherin repeats (CR9), a membrane-proximal extracellular domain (MPED) and a cytosolic region. Peptides corresponding to the CR9 and MPED regions bound Cry3Bb toxin with high affinities (23 nM and 40 nM) and significantly synergized Cry3Bb toxicity against A. diperinus larvae. Silencing of AdCad1 expression through RNA interference resulted in highly reduced susceptibility to Cry3Bb in A. diperinus larvae. The CR9 peptide fed with toxin to RNAi-treated larvae restored Cry3Bb toxicity. These results are evidences that AdCad1 is a functional receptor of Cry3Bb toxin and that exogenously fed CR9 peptide can overcome the effect of reduced AdCad1expression on Cry3Bb toxicity to larvae.     

华恢1号稻谷的大鼠慢性毒性试验研究

为了解长期喂养接触华恢1号稻谷是否会导致慢性毒性作用,尤其是进行性或不可逆的毒性作用以及致癌作用,本研究以SD大鼠为实验动物,进行了为期106周的慢性毒性试验.与普通稻谷对照组和基础饲料对照组比较,喂饲华恢1号稻谷106周的低、中、高剂量组SD大鼠,在一般临床症状、体重和食物利用率、血液学和血液生物化学指标、脏器重量和脏器系数、大体解剖学和病理组织学检查等各项观察指标上,均未见统计学意义和毒理学意义的差异.各组间,老年大鼠的肿瘤发生率为8.3%~10%,没有剂量反应关系,其发生部位主要在皮下,符合美国NIH Rodent 1980 catalogur SD大鼠乳腺肿瘤自然发病的正常范围.故认为华恢1号稻谷对SD大鼠没有明显的慢性毒性和致癌性.