转Bt基因作物毒素在土壤中降解特性的研究进展

总结了国内外转Bt基因作物在土壤中降解特性的研究结果,讨论了土壤有机、无机组分与毒素蛋白的关系,阐明了转基因毒素蛋白在土壤中的降解与影响因素,揭示了转Bt基因作物在土壤中降解的生态环境效应,并提出了今后应深入研究的问题和方向.     

Development and identification of glyphosate-tolerant transgenic soybean via direct selection with glyphosate

Glyphosate-tolerant soybean is the most widely planted genetically modified crop worldwide. However, soybean remains recalcitrant to routine transformation because of the low infection efficiency of Agrobacterium to soybean and lack of useful selectable markers. In this study, several Agrobacterium strains and cell densities were compared by transient expression of the GUS gene. The results showed that Agrobacterium strain Ag10 at cell densities of OD_(600) of 0.6–0.9 yielded the highest infection efficiency in Agrobacterium-mediated soybean cotyledonary node transformation system. Meanwhile, a simple and rapid method was developed for identification of glyphosate tolerance in putative T_0 transgenic plants, consisting of spotting plantlets with 1 μL Roundup~?. The whole cycle of genetic transformation could be shortened to about 3 mon by highly efficient selection with glyphosate during the transformation process and application of the spot assay in putative T_0 transgenic plantlets. The transformation frequency ranged from 2.9 to 5.6%. This study provides an improved protocol for development and identification of glyphosate-tolerant transgenic soybeans.     

Predicting the potential geographic distribution of Bactrocera bryoniae and Bactrocera neohumeralis(Diptera: Tephritidae) in China using MaxEnt ecological niche modeling

Bactrocera bryoniae and Bactrocera neohumeralis are highly destructive and major biosecurity/quarantine pests of fruit and vegetable in the tropical and subtropical regions in the South Pacific and Australia. Although these pests have not established in China, precautions must be taken due to their highly destructive nature. Thus, we predicted the potential geographic distribution of B. bryoniae and B. neohumeralis across the world and in particular China by ecological niche modeling of the Maximum Entropy(Max Ent) model with the occurrence records of these two species. Bactrocera bryoniae and B. neohumeralis exhibit similar potential geographic distribution ranges across the world and in China, and each species was predicted to be able to distribute to over 20% of the globe. Globally, the potential geographic distribution ranges for these two fruit fly species included southern Asia, the central and the southeast coast of Africa, southern North America, northern and central South America, and Australia. While within China, most of the southern Yangtze River area was found suitable for these species. Notably, southern China was considered to have the highest risk of B. bryoniae and B. neohumeralis invasions. Our study identifies the regions at high risk for potential establishment of B. bryoniae and B. neohumeralis in the world and in particular China, and informs the development of inspection and biosecurity/quarantine measures to prevent and control their invasions.     

Effect of three insect-resistant maizes expressing Cry1Ie,Cry1Ab/Cry2Aj and Cry1Ab on the growth and development of armyworm Mythimna separata(Walker)

Three transgenic maize events(IE09 S034, Shuangkang 12–5 and C0030.3.5) produced Cry1 Ie, Cry1 Ab/Cry2 Aj and G10-EPSPS, Cry1 Ab and EPSPS, respectively, all of which target the Asian corn borer. The oriental armyworm Mythimna separata(Walker) is the secondary target. In this study, the effects of the three Bt maizes on the development and survival of armyworm were studied. The results showed that IE09 S034 had insecticidal activity against 1 st instar larvae, and the survival rate of armyworm fed with Bt maize for 10 days was 46.2%, significantly lower than that of the control. The larvae at 3 rd–6 th instar were more tolerant of the Bt toxin than the early instar larvae. However, Shuangkang 12-5 had good insecticidal activity against 1 st–5 th instar larvae. The mortality was nearly 100% when the larvae were fed with Shuangkang 12-5 before 3 rd instar, and the toxin had quick-acting efficacy. This event significantly inhibited the development of armyworm; that is, the larval duration of the 3 rd and 4 th instar larvae fed with Shuangkang 12-5 was prolonged by 4.5 and 3.0 days, respectively. The pupal weight and egg number were also significantly lower than those of the control. For C0030.3.5, it could control 1 st–5 th instar larvae effectively. The mortality rates were all over 50% if 1 st–3 rd larvae were fed with this event. The pupal weight of 4 th–6 th instar larvae fed with Bt maize were only 53.9, 56.8 and 54.6%, respectively, compared to that of the control. The number of eggs laid was significantly less than the control. The results indicate that all three transgenic maize events exhibit the potential to provide effective control of early instar larvae of armyworm, which can be commercialized in future to control lepidoptera pests such as Asian corn borer and armyworm.     

花粉管通道法转化荔枝的初步研究

为开拓荔枝转基因育种新途径,以GUS基因作为报告基因,用花粉管通道法转化授粉后24 h的‘新球蜜荔’荔枝雌花,并统计座果率、成苗率、转化率。结果显示：共获得303株实生苗,经PCR检测和GUS染色法证实外源基因整合到4株荔枝苗基因组中,转化率为1.32%。此研究结果为荔枝生物技术育种提供了一种简单有效的途径。     

转Bt基因棉田棉铃虫对气候变暖与集约化种植的不对称响应

为明确全球气候变暖及农业集约化对转Bt基因棉田棉铃虫Helicoverpa armigera种群发生的影响,通过收集1987—2017年我国山东、河南及河北3省的棉花种植面积、棉铃虫发生面积及年平均温度,采用单因素方差分析法及广义线性模型分析比较转Bt基因棉花推广前后棉田棉铃虫种群的发生程度,分析棉铃虫的为害指数。结果显示,转Bt基因棉花推广前,山东、河南和河北3省的棉铃虫在严重发生年份的为害指数较轻微发生年份均显著增加,分别增加了1.01倍、2.03倍和69.33%;温度距平具有同样的趋势,严重发生年份的温度距平较轻微发生年份分别显著增加了1.91倍、2.33倍和2.29倍。转Bt基因棉花推广后,山东、河南和河北3省的棉铃虫在严重发生年份的为害指数较轻微发生年份仍显著增加,分别增加了1.47倍、1.92倍和1.25倍;温度距平表现出相反的趋势,轻微发生年份的温度距平较严重发生年份分别增加了2.00倍、1.94倍和2.01倍;而河南省和河北省在棉铃虫严重发生年份的棉花种植面积较轻微发生年份分别显著增加了75.94%及38.92%。表明转Bt基因棉花种植后显著改变了棉铃虫对全球气候变暖的响应,气候变暖降低了棉铃虫的为害指数,而棉花集约化种植增加了棉铃虫的为害指数。非转基因棉田的棉铃虫受自然因素的影响,转Bt基因棉田的棉铃虫受自然及人为因素的双重影响。     

中国野生毛葡萄芪合酶基因VqSTS11和VqSTS23调控抗白粉病的研究

利用同源克隆法得到抗白粉病的中国野生毛葡萄‘丹凤–2’芪合酶基因VqSTS11和VqSTS23的开放阅读框,并构建过表达载体;通过器官发生途径诱导不抗白粉病的欧洲葡萄‘无核白’分生愈伤组织并采用农杆菌介导法对其进行转化;经过PCR检测和Western blot鉴定,获得了5株VqSTS11超量表达植株和3株VqSTS23超量表达植株;人工接种白粉菌发现,转基因植株中白粉菌菌丝生长速度慢,孢子萌发受到一定的抑制,并且转基因植株中芪合酶基因相对表达量升高,抗病相关基因表达上调,芪类物质含量积累增多。本研究结果进一步证明中国野生毛葡萄‘丹凤–2’芪合酶基因VqSTS11和VqSTS23对白粉菌具有抗性,‘丹凤–2’可以为改良欧洲葡萄品种抗病性提供抗病基因,作为抗病育种的资源。     

棉蚜茧蜂对不同品种、不同生育期棉花的趋性行为反应

【目的】研究棉蚜茧蜂对不同品种、不同生育期棉花的趋性行为反应,为了解天敌昆虫与寄主之间关系,利用棉蚜茧蜂对棉蚜等害虫进行防控。【方法】以生产上大面积种植的GK-12(对照为泗棉3号)、新棉33B(亲本为新棉33)和SGK321(亲本为石远321)等3组棉花品种为材料,于棉花7叶期、现蕾前期和现蕾期,设计无虫棉植株、被棉蚜为害后剔除虫体的植株以及棉蚜+有虫株等3种不同处理,借助“Y”型嗅觉仪,检测棉蚜茧蜂在棉花不同生育期对这3种不同处理的趋性。【结果】棉蚜茧蜂无法识别健康的常规棉和转基因棉花植株;对不含棉蚜的被害棉来说,转基因棉对棉蚜茧蜂更具吸引力。而对含有棉蚜的有害棉来说,除7叶期GK12、新棉33B和现蕾期GK12这3组处理外,其他各组的转基因棉对棉蚜茧蜂均具较强的吸引作用。【结论】两类不同的棉花品种对棉蚜茧蜂不存在排斥性,棉蚜为害转基因棉花后更能吸引棉蚜茧蜂。     

转Cry抗虫基因玉米对家蚕的安全性评价

家蚕可能通过取食漂移到桑叶上的玉米花粉从而受到转基因玉米中表达的Cry蛋白的影响。实验采用室内生物测试的方法评价了转cry1Ab和cry2Ab基因玉米GAB-3花粉对家蚕可能产生的影响,并采用在饲料中掺入蛋白的方式检测了转基因玉米中广泛使用的6种Cry杀虫蛋白对家蚕的毒性。当桑叶上GAB-3花粉密度为50粒·cm^-2时,对家蚕幼虫存活率无显著影响,达500粒·cm^-2时,家蚕14 d存活率为0;以10粒·cm^-2的GAB-3花粉饲喂家蚕幼虫7 d对其体重无显著不利影响,但延长饲喂时间或者当GAB-3花粉密度为50粒·cm^-2时,家蚕的体重显著低于对照组;转基因和非转基因玉米花粉处理14 d或更长时间的家蚕体重均低于无花粉处理组。与非转基因对照处理组相比,低于100粒·cm^-2的转基因玉米GAB-3花粉处理组家蚕的化蛹率、茧重、茧壳重和蛹重无显著差异,转基因玉米和非转基因玉米花粉处理均会延长家蚕幼虫的发育历期。GAB-3花粉对家蚕7 d的LC₅₀为261.18粒·cm^-2,随着处理时间延长,LC₅₀下降。测试的6种Bt杀虫蛋白对家蚕的毒性依次为Cry1C>Cry1Fa>Cry1B>Cry2A>Cry1Ab>Cry1Ac。目前,在中国接近商业化的转基因玉米中多采用的Bt杀虫蛋白为Cry1Ab和Cry2A,二者对家蚕的毒性较低,并且在实际生产中,家蚕接触到的转基因玉米花粉密度较低,因此转Cry抗虫基因玉米对家蚕的风险较低。