Thrips-mediated impacts from transgenic rice expressing Cry1Ab on ecological fitness of non-target predator Orius tantilus(Hemiptera:Anthocoridae)

Various rice lines have been genetically modified with genes from Bacillus thuringiensis(Bt) to continuously produce Bt insecticidal proteins against lepidopteran larvae. The Bt insecticidal protein constantly expresses in the plants to create an opportunity for non-target herbivores to acquire and convey the protein to their predators or parasitoids across trophic levels. This paper evaluates the effects of Bt rice(namely, Kemindao 1(KMD1) and Kemindao 2(KMD2)) expressing Cry1 Ab as compared to its non-Bt control line, Xiushui 11 on non-target predator Orius tantilus(a generalist predatory anthocorid of thrips) under laboratory and field conditions. To measure several biological parameters such as total nymphal duration and fecundity of this bug, it was reared on thrips and pollens of KMD1 and KMD2 as compared to their control under laboratory conditions. By comparison with the control, Bt rice did not significantly affect main life-history characteristics(total nymphal duration, female adult longevity, oviposition period and fecundity) of this anthocorid preying on Bt rice-fed thrips along with Bt rice pollens, except that the fecundity of this predator for KMD1 was distinctly lower as compared with KMD2 or the control. Enzyme-linked immunosorbent assay(ELISA) results showed that no Cry1 Ab protein was detected in this predator fed on thrips or rice pollen from Bt rice but was in Bt rice pollens. With the beat plate, plastic bag and color trap sampling methods, two-year field monitoring of O. tantilus abundance demonstrated that Bt rice had no significant detrimental effects on the population dynamics and seasonal average densities of this predatory anthocorid as compared with the control. Thus, it is suggested that growing our tested Bt rice(KMD1 and KMD2) producing Cry1 Ab will pose a negligible risk to the anthocorid, O. tantilus.     

Functional and numerical responses of Cyrtorhinus lividipennis to eggs of Nilaparvata lugens are not affected by genetically modified herbicide-tolerant rice

To safely and sustainably utilize genetic breeding techniques for crop production, greater understanding of the potential effects of genetically modified herbicide-tolerant (GMHT) crops on the ecological functions of predators is required. In the laboratory, we examined the functional and numerical responses of Cyrtorhinus lividipennis Reuter to eggs of brown planthopper (BPH), Nilaparvata lugens (Stål), which were reared on GMHT rice Bar68-1; the untransformed parental cultivar, D68; or a BPH-susceptive rice variety, Taichung Native 1. All stages of nymphs and female adult of C. lividipennis, either on GMHT rice or control plants, exhibited typical type II functional responses when fed on BPH eggs; the attacking rate and handling time of C. lividipennis on GMHT rice Bar68-1 was not significantly different from that on D68. The numerical responses of C. lividipennis on GMHT rice or controls fit Beddington’s model; there were no significant differences in the parameters of numerical responses between GMHT rice Bar68-1 and D68. The results indicated that the functional and numerical responses of C. lividipennis to BPH eggs are not affected by GMHT rice Bar68-1.     

利用分子标记辅助选择技术培育抗虫水稻品种的研究

Bt基因是从苏云金芽孢杆菌中克隆出的针对鳞翅目害虫的抗虫基因,经过基因工程方法人工改造已经获得Cry1Ab/Ac、Cry1C等抗虫基因。以云南主栽水稻品种楚粳28为受体,以携带Bt抗虫基因的"华恢1号"、"RJ-5"和"T1C-19"分别作为供体,利用分子标记辅助选择(MAS)技术进行回交育种,选育成携带Bt抗虫基因水稻新品系。结合农艺性状表现,获得了云抗虫稻1号、云抗虫稻2号、云抗虫稻3号Bt蛋白高表达的水稻抗虫品系。这些抗虫品系为云南省抗虫水稻的遗传改良和生产应用提供了基因资源和应用基础。     

转cry1C和cry2A基因Bt水稻对白背飞虱生长、发育及繁殖的继代影响

转Bt基因水稻对非靶标节肢动物的影响是转基因水稻安全性评价的重要组成部分。目前,已开展了大量关于转Bt基因水稻对非靶标害虫安全性评价的研究,但多限于1代,不能完全反映田间情况。试验以转Bt基因水稻T1C 19(含cry1C基因)和T2A 1(含cry2A基因)以及其亲本非Bt水稻MH63为材料,在室内条件下连续饲养白背飞虱4代,研究转Bt水稻对非靶标害虫白背飞虱生长发育和繁殖的继代效应,以明确T1C 19和T2A 1水稻对白背飞虱的潜在影响。结果表明,白背飞虱在3种水稻品种上连续取食4代以后,其生长发育(若虫发育历期、若虫存活率、雌成虫体重)和繁殖(产卵量和卵孵化率)指标均没有受到水稻品种的显著影响。可见,供试的T1C 19和T2A 1对白背飞虱无显著影响。     

转Bt(Cry1Ab)基因对水稻光合特性及光合产物积累的影响

 【目的】明确外源Bt基因插入对水稻倒1叶光合速率及光合作用相关生理特性的影响。【方法】以转Bt基因水稻及亲本水稻为试材,研究盆栽及田间条件下转Bt基因及亲本水稻苗期、拔节期、抽穗期和成熟期倒1叶光合特性及其相关光合酶活性、光合产物积累的动态变化。【结果】转Bt基因及亲本水稻生理活动峰值均出现在拔节期。与亲本水稻相比,转Bt基因水稻苗期叶片净光合速率显著低于亲本;而拔节期和抽穗期,转Bt基因水稻倒1叶净光合速率、叶绿素含量和乙醇酸氧化酶活性显著高于亲本水稻（P＜0.05）,且拔节期转Bt水稻倒1叶气孔导度和胞间CO2浓度也显著高于亲本水稻（P＜0.05）;成熟期,转Bt基因与亲本水稻倒1叶光合特性无显著性差异（P＞0.05）。【结论】与亲本水稻相比,外源Bt基因的插入对水稻叶片光合特性产生短暂影响,但这种影响不具有持续性。     

Impacts of Environmental Factors on Degradation of Cry1Ab Insecticidal Protein in Leaf-Blade Powders of Transgenic Bt Rice

The determination of the environmental fate of Bt insecticidal protein released by Bt rice plants in paddy soils is a key issue in its ecological risk assessment. In this study, the impacts of soil water content, pH, and temperature on the degradation of Cry1Ab protein expressed in the leaves of Bt rice KMD2 were studied in the laboratory. Three types of paddy soils were used, i.e., blue clayey paddy soil, pale paddy soil on quaternary red soil, and marine-fluvigenic yellow loamy paddy soil. Ground powders of KMD2 leaf blades were mixed with each type of soil, and degradation dynamics of Cry1Ab were measured using enzyme-linked immunosorbent assay (ELISA). The degradation rate of Cry1Ab was high at the early experimental stage, but slowed down steadily at middle and later stages, which could be described by exponential equations, with the half-life period of degradation determined as 1.8-4.0 d. The soil water content, pH, and temperature could affect the degradation of Cry1Ab, but the effects of soil pH and temperature were relatively greater. In general,Cry 1 Ab degradations were slower under lower soil pH and temperature conditions, especially for marine-fluvigenic yellow loamy paddy soil.     

Impacts of Environmental Factors on Degradation of CrylAb Insecticidal Protein in Leaf-Blade Powders of Transgenic Bt Rice

The determination of the environmental fate of Bt insecticidal protein released by Bt rice plants in paddy soils is a key issue in its ecological risk assessment. In this study, the impacts of soil water content, pH, and temperature on the degradation of CrylAb protein expressed in the leaves of Bt rice KMD2 were studied in the laboratory. Three types of paddy soils were used, i.e., blue clayey paddy soil, pale paddy soil on quaternary red soil, and marine-fluvigenic yellow loamy paddy soil. Ground powders of KMD2 leaf blades were mixed with each type of soil, and degradation dynamics of Cry lAb were measured using enzyme-linked immunosorbent assay （ELISA）. The degradation rate of CrylAb was high at the early experimental stage, but slowed down steadily at middle and later stages, which could be described by exponential equations, with the half-life period of degradation determined as 1.8-4.0 d. The soil water content, pH, and temperature could affect the degradation of CrylAb, but the effects of soil pH and temperature were relatively greater. In general, CrylAb degradations were slower under lower soil pH and temperature conditions, especially for marine-fluvigenic yellow loamy paddy soil.     

影响Bt稻离体叶中Cry1Ab杀虫蛋白降解的环境因子研究

 【目的】研究转Bt基因水稻表达的外源Bt杀虫蛋白在土壤中的环境去向，以便进行转BT基因水稻的生态风险性评价。【方法】室内采用ELISA法，研究了转Bt基因水稻克螟稻2号（KMD2）粉碎叶片中Cry1Ab杀虫蛋白在3种水稻土，即青紫泥田、黄筋泥田和黄松田土中不同土壤含水量、土壤pH值和温度条件下的降解动态。【结果】供试叶片粉中Cry1Ab蛋白在3种水稻土中的降解动态均可用一级化学反应动力学指数方程来拟合，降解半消减期t0.5为1.8～4.0 d。【结论】土壤含水量、pH和温度对Cry1Ab蛋白降解速率均有一定影响，但pH和温度的影响更为明显。通常pH较低的酸性土壤和低温不利于土壤中Cry1Ab蛋白的降解,特别是在酸性黄松田中降解最慢。     

Transgenic cry1Ab/vip3H+epsps Rice with Insect and Herbicide Resistance Acted No Adverse Impacts on the Population Growth of a Non-Target Herbivore,the White-Backed Planthopper,Under Laboratory and Field Conditions

Numerous Bt rice lines expressing Cry protein derived from Bacillus thuringiensis Berliner (Bt) have been developed since 1989. However, the potential risks posed by Bt rice on non-target organisms still remain debate. The white-backed planthopper (WBPH), Sogatella furcifera (Horváth), is one of the most economically important insect pests of rice in Asian countries and also one of the main non-target herbivores of transgenic rice. In the current study, impacts of transgenic cry1Ab/vip3H+epsps rice (G6H1) with both insect and herbicide resistance on WBPH were evaluated to ascertain whether this transgenic rice line had potential risks for this sap-sucking pest under laboratory and field conditions. The laboratory results showed that no significant difference in egg developmental duration, nymphal survival rate and female fecundity was found for WBPH between G6H1 and its non-transgenic isoline (XS110). However, the development duration of nymphs was significantly shorter and female longevity significantly longer when WBPH fed on G6H1 by comparison with those on its control. To verify the results found in laboratory, a 3-yr field trial was conducted to monitor WBPH population using both the vacuum-suction machine and beat plate methods. Although the seasonal density of WBPH nymphs and total density of nymphs and adults were not significantly affected by transgenic rice regardless of the sampling methods, the seasonal density of WBPH adults in transgenic rice plots was slightly lower than that in the control when using the vacuum-suction machine. Based on these results both from laboratory and field, it is clear that our tested transgenic rice line will not lead higher population of WBPH. However, long-term field experiments to monitor the population dynamics of WPBH at large scale need to be conducted to confirm the present conclusions in future.     

No detrimental effect of Bt maize pollen containing Cry1Ab/2Aj or Cry1Ac on adult green lacewings Chrysoperla sinica Tjeder

Adult Chrysoperla sinica Tjeder is a common pollen feeder in maize fields. They are thus directly exposed to insecticidal proteins by consumption of genetically engineered maize pollen containing Bacillus thuringiensis (Bt) proteins. Here we assessed the potential effects of Cry1Ab/2Aj- or Cry1Ac-containing Bt maize pollen on the fitness of adult C. sinica via a dietary-exposure assay under laboratory conditions. Survival, pre-oviposition, fecundity and adult dry weight did not differ between adult C. sinica consuming Bt or the corresponding non-Bt maize pollen. The stability of the Cry protein in the food sources and uptake of the Cry protein by adult C. sinica during the feeding experiment were confirmed by ELISA. These results demonstrate that adult C. sinica are not affected by the consumption of Cry1Ab/2Aj- or Cry1Ac-containing maize pollen, suggesting that production of Bt maize expressing cry1Ab/2Aj or cry1Ac genes will pose a negligible risk to adult C. sinica.     

转Bt基因水稻稻米的诱变活性研究

利用微核、精子畸变和Ames试验检测了转Bt基因水稻稻米对小鼠骨髓嗜多染红细胞(polychromatic erythrocytes,PCE)微核率(micronucleus frequency,MN%)和小鼠精子畸形发生率(sperm malformation rate)及组氨酸营养缺陷型鼠伤寒沙门氏菌株回变菌落数的影响。结果表明,在本实验条件下,Bt水稻稻米对小鼠体细胞和性细胞均无诱变活性,且无剂量效应;该受试物对TA97a、TA98、TA100和TA102菌株无论在有无代谢活化系统存在的条件下,各剂量组回变菌落数均处于正常水平。     

用Envirologix Cry1Ab/Cry1Ac试剂盒快速测定转基因水稻Bt杀虫蛋白含量的研究

 用 Envirologix Cry1Ab/Cry1Ac平板试剂盒检测了两个转 cry1Ab的水稻品系克螟稻 1号 ( KMD1)、克螟稻 2号 ( KMD2 ) ,及未转化的对照品种秀水 11米粒中的 Bt杀虫蛋白含量。结果表明 ,该试剂盒标样制作的标准曲线相关系数为 0 .985～ 0 .998,在 0 .0 5或 0 .0 1水平上显著。同批次试剂盒的不同试验及不同批次试剂盒的测定值均差异不显著。最低检测剂量达 0 .5 ng/g,每次测试时间比 Western dot blotting方法缩短约 2 h。试验表明 ,该试剂盒是定量检测转基因水稻 Bt毒蛋白表达的一种理想产品     

转cry1Ab基因抗虫水稻的培育

采用农杆菌介导的遗传转化法,将cry1Ab基因导入优良三系恢复系明恢63,共获得了92个独立转化株,其中13株为单拷贝。通过发芽试验,获得了11个单拷贝转基因纯合系。ELISA检测结果表明:不同株系其Bt蛋白含量不一样,但杂种的Bt蛋白含量与其亲本一致。室内人工接虫试验及田间抗虫性试验初步表明:5个纯合株系表现高度抗性,且农艺性状与原品种没有显著差异。由此说明,所获得的这些单拷贝转基因株系可作为育种材料,用于抗虫水稻的培育。     

不同Bt蛋白对捕食性天敌大草蛉的生态安全性评价

【目的】明确转基因棉花中表达Cry1Ac、Cry1F和Cry2Ab蛋白对我国Bt棉田中主要捕食性天敌大草蛉（Chrysopa pallens）的潜在影响。【方法】通过在大草蛉人工饲料中添加高剂量Bt蛋白的方法,评价Cry1Ac、Cry1F和Cry2Ab蛋白对大草蛉重要生命表参数（4龄幼虫体重、幼虫发育历期、化蛹率、蛹重、蛹发育历期、羽化率、成虫体重和产卵量）的影响,以不添加杀虫物质的大草蛉纯人工饲料作为阴性对照,以添加PA（砷酸二氢钾,KH₂AsO₄）的大草蛉人工饲料作为阳性对照;同时,利用双抗体夹心酶联免疫吸附法（DAS-ELISA）测定取食Bt蛋白处理饲料后,大草蛉幼虫、蛹以及成虫体内的Bt蛋白浓度;利用ELISA法和敏感昆虫生物测定法,检测新鲜饲料和在试验环境条件下暴露2 d的处理饲料中Bt蛋白的稳定性和生物活性;此外,利用酶活性测定的方法,比较取食空白对照饲料、Bt蛋白处理饲料或PA处理饲料后大草蛉体内主要消化酶（总蛋白酶、类胰蛋白酶、类凝乳蛋白酶和氨肽酶）、解毒酶（α-乙酸萘酯酯酶、羧酸酯酶、谷胱甘肽-S-转移酶、乙酰胆碱酯酶、酸性磷酸酶和碱性磷酸酶）和保护酶（超氧化物歧化酶、过氧化物酶和过氧化氢酶）的活性。【结果】生命表评价结果表明,在大草蛉人工饲料中添加高浓度单独Bt蛋白或Bt蛋白混合物,对大草蛉4龄幼虫体重、幼虫发育历期、化蛹率、蛹重、蛹发育历期、羽化率、成虫体重和产卵量无显著性不利影响,但饲料中添加PA却能够使大草蛉幼虫和蛹发育历期极显著延长,4龄幼虫体重、化蛹率、蛹重、羽化率、成虫体重和产卵量极显著降低;大草蛉体内Bt蛋白浓度测定结果显示,大草蛉取食Bt蛋白处理饲料后,其幼虫、蛹及成虫体内均含有一定量的Bt蛋白;ELISA和敏感昆虫生物测定结果表明,新鲜准备和在试验环境条件下暴露2 d的Bt蛋白处理饲料,均含有高剂量且具有生物活性的Bt蛋白,因此,大草蛉在整个生物测定过程中接触到的均为高浓度的、具有生物活性的Bt蛋白;此外,取食Bt蛋白处理饲料,对大草蛉幼虫和成虫体内主要消化酶、解毒酶和保护酶活性无显著性影响,但取食PA处理饲料能使大草蛉幼虫和成虫体内氨肽酶活性极显著降低,其他所测消化酶、解毒酶和保护酶活性显著升高。【结论】大草蛉对3种供试Bt蛋白（Cry1Ac、Cry1F和Cry2Ab）不敏感,取食这3种Bt蛋白对大草蛉生长发育及其体内主要消化酶、解毒酶和保护酶活性没有显著不良影响,本研究所建立的生物评价体系还可用于评价其他新型转基因抗虫植物中表达杀虫蛋白对大草蛉的生态安全性。     

转双价双Bt基因(Cry1Ac+Cry2Ab)抗虫棉栽培地生存竞争能力研究

为建立国家转双价双Bt抗虫基因棉环境安全评价技术,对转双价双Bt基因(Cry1Ac+Cry2Ab)抗虫棉栽培地生存竞争能力进行研究,结果表明,转双价双Bt基因棉花与对照赣棉11相比,各生育期株高生长具有显著竞争优势,优势值3.48～4.75 cm;吐絮期棉覆盖度竞争优势超对照46.77个百分点,达显著水平;产量竞争力优势籽棉超对照1 013.85 kg/hm2,皮棉超对照433.20 kg/hm2,均未达到显著水平;发芽率竞争优势极显著,超过对照2.75个百分点。与非转基因常规棉相比,转双价双Bt抗虫基因棉生存竞争能力优势显著。     

转Bt基因水稻的碳代谢特性

【目的】评价外源Bt基因导入对水稻碳代谢特性的影响。【方法】以转Bt基因水稻克螟稻1号及其非转基因亲本秀水11,以及克螟稻1号与3个杂交水稻恢复系明恢63、R3027和99亚162杂交和连续回交而育成的农艺性状和抗虫性稳定品系的3对近等基因系为材料,对叶绿素与可溶性糖含量、RuBP 羧化酶、蔗糖合成酶及蔗糖磷酸合成酶活性、干物质及有机碳积累量等碳代谢指标进行了测定。【结果】分蘖盛期克螟稻1号的叶绿素a含量、可溶性糖含量、干物质和有机碳含量均极显著低于秀水11（P＜0.01）,叶绿素b含量、蔗糖合成酶和蔗糖磷酸合成酶活性显著低于秀水11（P＜0.05）,但其它3对Bt水稻与非Bt水稻间所有生理指标均无显著差异;齐穗期克螟稻1号蔗糖磷酸合成酶活性显著高于秀水11,而干物质和有机碳积累量则显著低于秀水11;BtR3027蔗糖合成酶活性显著低于R3027,而Bt99亚162可溶性糖含量和蔗糖磷酸合成酶活性则显著高于99亚162;成熟期所有Bt水稻与各自非Bt水稻间干物质重和有机碳积累量差异均不显著。【结论】克螟稻1号大多数碳代谢指标的显著变化主要是由无性系变异引起的;3对近等基因系中Bt基因对个别碳代谢指标的影响是短暂的,且与Bt基因所处的遗传背景有关。     

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.     

温度对黑肩绿盲蝽生长发育和繁殖的持续影响

黑肩绿盲蝽（Cyrtorhinus lividipennis Reuter）是稻田重要害虫褐飞虱的主要天敌,人工饲养和大田释放黑肩绿盲蝽,能有效控制褐飞虱。在实验室研究了不同温度（19,23,27和31℃）对黑肩绿盲蝽生长发育和繁殖的连续3个世代的持续影响。结果表明,19℃条件下随着世代发展,雌若虫历期缩短,子代数量降低;31℃条件下随着世代发展,雌成虫寿命缩短,子代数量降低;其他温度对若虫存活率、雄若虫历期、雌虫体重、成虫寿命和子代数量持续影响不显著。试验结果说明在相对低温19℃和相对高温31℃下,黑肩绿盲蝽的生长发育和繁殖受到抑制。     

转Bt基因抗虫玉米根茬和根际土壤中Cry1Ab杀虫蛋白的田间降解动态

【目的】研究转cry1Ab杀虫蛋白基因玉米收获后玉米根茬及其根际土壤中Cry1Ab杀虫蛋白的降解动态,比较两种Bt玉米根茬和根际土壤中Cry1Ab杀虫蛋白的降解速度。【方法】以两种表达Cry1Ab杀虫蛋白的Bt抗虫玉米MON810和Bt11为材料,采用ELISA方法测定玉米收获后根茬残体和根际土壤中Cry1Ab杀虫蛋白的田间降解动态。【结果】转Bt基因玉米根茬残体和根际土壤中杀虫蛋白是逐渐降解的,Bt玉米MON810根茬中Cry1Ab杀虫蛋白含量较高,降解的速度也较慢,收获后8个月时还不能完全降解;Bt玉米Bt11根茬中Cry1Ab杀虫蛋白含量较低,降解速度比MON810根茬中Cry1Ab杀虫蛋白降解速度快,到7个月时已检测不到Cry1Ab杀虫蛋白。Bt玉米MON810根际土壤中Cry1Ab杀虫蛋白的降解较Bt11的慢,MON810和Bt11根际土壤分别在8个月和7个月时检测不到Cry1Ab杀虫蛋白。【结论】种植过Bt11和MON810抗虫玉米的田块,在第二年春播农作物已经出土时,其根茬和根际土壤中残留的Cry1Ab杀虫蛋白尚不能完全降解,还有少量残留。     

Studies on Rapid Quantitative Analysis of Bt Toxin by Using Envirologix Kits in Transgenic Rice

Investigations were done on the usefulness of Envirologix Cry1Ab/Cry1Ac Plate kits for quantitative analysis of Bt toxin content in transgenic rice grains. Two transgenic rice lines: Kemingdao 1 (KMD1) and Kemingdao 2 (KMD2), transformed with a cry1Ab gene, and their parental variety, cv.Xiushui 11, were used as positive and negative samples. Results showed that the correlation coefficients as high as 0. 985 - 0. 998, significant at probability level of 0.05 or 0.01, were obtained for linear regression equations by using the appended calibrators of the kits. No significant differences were detected for values of same rice sample obtained from different trials or by using different lots of the product (kit). The detectable Bt toxin content by this method could be as low as 0.5 ng/g. The Envirologix Kit could be useful for rapid quantitative detection of Bt toxin in rice grains because of its preciseness, simplicity and time saving.