The susceptibility of the Asian corn borer, Ostrinia furnacalis to Bacillus thuringiensis (Bt) formulation and Bt corn was evaluated using insect bioassays for 6 years. Four strains of O. furnacalis were developed by ...The susceptibility of the Asian corn borer, Ostrinia furnacalis to Bacillus thuringiensis (Bt) formulation and Bt corn was evaluated using insect bioassays for 6 years. Four strains of O. furnacalis were developed by laboratory selection from the laboratory strain reared on a non-agar semi-artificial diet. The RR-1 strain was exposed to a commercial formulation of B. thuringiensis subsp. kurstaki (Btk) incorporated into the artificial diet,the RR-2 strain was exposed to Bt corn (MON810) tissue incorporated into the diet, and the SS-1 and SS-2 strains were reared on the standard diet with or without non-Bt corn tissues material. Decreasing susceptibility of O. furnacalis to Bt and to Bt corn were found in each selected strain although the ED50 and larval weight fluctuated from generation to generation. The resistance of Bt-exposed strain (RR-1) to Btk increased 48-fold by generation 39; the Bt corn-exposed strain (RR-2) increased its resistance 37-fold to Btk by generation 24. No larvae of SS-1 survived when they were exposed to the leaves of Bt corn, Bt11 and MON810. However, 2-54% of the RR-1 (generation 46) and RR-2 (generation 20) larvae survived a 3 day-exposure to the leaves of Bt11 and MON810. The survival of both selected strains on Bt corn silk increased by 10-69%, and the larval weights after many generations selection were increased by 15-22% compared with the unselected susceptible strain. The young larvae were much more susceptible to Bt than older larvae. The highest mortality occurred when the larvae were exposed to Bt at the neonate stage. All of the results suggested that ACB could not only develop resistance to Bt preparation but also to Bt corn. Bt had significant effects on the growth and development of Asian corn borer than on the larval mortality. In order to maintain the long-term effectiveness of Bt pesticide and Bt corn, the resistance management should pay much attention to the larvae that may have opportunities to grow and developed on non-Bt corn or alternate hosts before they attack the Bt corn plants and the survival of larvae after Bt application.展开更多
The S-endotoxin genes of Bacillus thuringiensis (Bt) and proteinase inhibitor (PI) genes are two kinds of genes popularly used for developing transgenic plants resistant to insect pests. To clarify whether there is an...The S-endotoxin genes of Bacillus thuringiensis (Bt) and proteinase inhibitor (PI) genes are two kinds of genes popularly used for developing transgenic plants resistant to insect pests. To clarify whether there is any risk concerning the effects of pollens from these transgenic crops on non-target insects with economic importance, such as the effects on the growth and development as well as cocoon quality of the silkworm, Bombyx mori Linnaeus, a series of feeding experiments were conducted, using pollens from transgenic cotton or corn containing cry 1Ac, cry1A+CpTI or crylAb genes, compared with pollens from non-transgenic normal cotton and corn as well as the non-pollen treatment. In contrast to the latter ones, pollens from transgenic plants showed no significant adverse effects on larval mortality, cocoon weight, pupa weight, cocoon shell weight, pupation rate, emergence rate and fecundity of the silkworm after neonates were fed with the pollens for 72 h. In addition, no dosage effects of pollens were found. Though the duration of 1st instar larvae was prolonged in the case of feeding with transgenic pollens as compared with those of the non-pollen treatment , but they were not significantly different from those fed with pollens from non-transgenic cotton or corn. Meanwhile, the body weight of the 3rd instar molters fed with transgenic pollens was obviously different from those for non-pollen treatment, and was all significantly heavier than that of the controls. Consequently, it is considered that the adverse effect of pollens from transgenic insect-resistant cotton and corn on the growth and development of the silkworm is negligible.展开更多
The fall armyworm,Spodoptera frugiperda(J.E.Smith),is a major target pest of Bt crops(e.g.,corn,cotton,and soybean)in North and South America.This pest has recently invaded Africa and Asia including China and the inva...The fall armyworm,Spodoptera frugiperda(J.E.Smith),is a major target pest of Bt crops(e.g.,corn,cotton,and soybean)in North and South America.This pest has recently invaded Africa and Asia including China and the invasion has placed a great threat to the food security in many countries of these two continents.Due to the extensive use of Bt crops,practical resistance of S.frugiperda to Cry IF corn(TC 1507)with field control problems has widely occurred in Puerto Rico,Brazil,Argentina,and the mainland United States.Analyzing data generated from decade-long studies showed that several factors might have contributed to the wide development of the resistance.These factors include(1)limited modes of action of Bt proteins used in Bt crops;(2)cross-resistance among Cryl proteins;(3)use of nonhigh dose Bt crop traits;(4)that the resistance is complete on Bt corn plants;(5)abundant in initial Cry IF resistance alleles;and(6)lack of fitness costs/recessive fitness costs of the resistance.The long-term use of Bt crop technology in the Americas suggests that Bt corn can be an effective tool for controlling S.frugiperda in China.IRM programs for Bt corn in China should be as simple as possible to be easily adopted by small-scale growers.The following aspects may be considered in its Bt corn IRM programs:(1)use of only"high dose^traits for both S.frugiperda and stalk borers;(2)developing and implementing a combined resistance monitoring program;(3)use“gene pyramiding”as a primary IRM strategy;and(4)if possible,Bt corn may not be planted in the areas where S.frugiperda overwinters.Lessons and experience gained from the global long-term use of Bt crops should have values in improving IRM programs in the Americas,as well as for a sustainable use of Bt corn technology in China.展开更多
Bt corn is one of the top three large-scale commercialized transgenic crops around the world. It is increasingly clear that the complementary durable approaches for pest control, which combine the endogenous defense o...Bt corn is one of the top three large-scale commercialized transgenic crops around the world. It is increasingly clear that the complementary durable approaches for pest control, which combine the endogenous defense of the crop with the introduced foreign genes, are promising alternative strategies for pest resistance management and the next generation of insect-resistant transgenic crops. In the present study, we tested the inducible effects of exogenous jasmonic acid （JA） on direct-defense chemical content, Bt protein concentration, and related gene expression in the leaves of Bt corn cultivar 34B24 and non-Bt cultivar 34B23 by chemical analysis, ELISA, and RT-PCR. The results show that the expression of LOX, PR-2a, MPI, and PR-I genes in the treated leaf （the first leaf） was promoted by exogenous JA both in 34B24 and 34B23. As compared with the control, the concentration of DIMBOA in the treated leaf was significantly increased by 63 and 18% for 34B24 and 34B23, respectively. The total phenolic acid was also increased by 24 and 12% for both 34B24 and 34B23. The Bt protein content of 34B24 in the treated leaf was increased by 13% but decreased significantly by 27% in the second leaf. The induced response of 34B24 was in a systemic way and was much stronger than that of 34B23. Those findings indicated that there is a synergistic interaction between Bt gene and internally induced chemical defense system triggered by externally applied JA in Bt corn.展开更多
The research cxamined the effects of microbial and novel insecticidal control strategies and also Irichogramma pretiosum on the I,epidoptera： Crambidae, the European corn borer （ECB）, （Ostrinia nubilalis）. The tr...The research cxamined the effects of microbial and novel insecticidal control strategies and also Irichogramma pretiosum on the I,epidoptera： Crambidae, the European corn borer （ECB）, （Ostrinia nubilalis）. The treatments included ~ino^d, from bacteria the entomopathogenic fungus Beauveria bassiana, the egg parasitoid Trichogramma pretiosum, and foliar applied Bt spray, and t^vo combinations Bearveria bassiana plus Bt spray and Trichogramma pretiosum and spinosad. The infestations by the European corn borer larvae on stalks of corn were very＂ severe in all the control treatments both 2006 and 2007. The microbial treatments caused various levels of European corn borer mortality. In all the parameters there was a significant difference between the control and other treatments with a P 〈 0.00 l. In this research, treatment with spinosad emerged as the most effective biological agent in the control of the European corn borer. The treatments had no significant effects on the relative abundance and composition of non-target arthropods （P 〉 0.05）. This research is relevant in boosting underutilized control strategies and increasing stakeholder adoption of integrated pest management practices and thereby＇ reducing the use of conventional insecticides especially for orgamc thrmers. This is very important especially in certain countries where the commumities are skeptical about consuming transgenic crops.展开更多
【目的】Bt(Bacillus thuringiensis)玉米(Zea may sL.)是全球商品化程度最快的抗虫转基因作物之一,协调利用其内在防御机制和人工导入抗性是目标害虫抗性风险综合管理和第2代抗虫转基因作物培育的主要策略之一。【方法】采用基因表达...【目的】Bt(Bacillus thuringiensis)玉米(Zea may sL.)是全球商品化程度最快的抗虫转基因作物之一,协调利用其内在防御机制和人工导入抗性是目标害虫抗性风险综合管理和第2代抗虫转基因作物培育的主要策略之一。【方法】采用基因表达分析、化学物质分析和ELISA蛋白定量方法,研究外施信号物质茉莉酸对Bt玉米34B24(Mon810)及其同源常规玉米34B23幼苗叶片直接防御物质含量及其相关基因表达的影响。【结果】外源茉莉酸处理能诱导34B24和34B23处理叶(第1叶)中LOX、PR-2a、MPI和PR-1基因的表达,第1叶丁布含量分别比对照增加63%和18%、总酚含量分别增加24%和12%。茉莉酸处理使34B24第1叶中的Bt蛋白含量增加了13%,但第2叶中的显著降低了27%。与34B23相比,茉莉酸对34B24的诱导作用更强,并具有系统性。【结论】人工外施茉莉酸的条件下,Bt玉米人工导入抗性(Bt基因)和自身化学防御过程之间的互作关系是协同的。展开更多
基金the National 863 Program(2002AA212161) the National Natural Science Foundation of China(39970489).
文摘The susceptibility of the Asian corn borer, Ostrinia furnacalis to Bacillus thuringiensis (Bt) formulation and Bt corn was evaluated using insect bioassays for 6 years. Four strains of O. furnacalis were developed by laboratory selection from the laboratory strain reared on a non-agar semi-artificial diet. The RR-1 strain was exposed to a commercial formulation of B. thuringiensis subsp. kurstaki (Btk) incorporated into the artificial diet,the RR-2 strain was exposed to Bt corn (MON810) tissue incorporated into the diet, and the SS-1 and SS-2 strains were reared on the standard diet with or without non-Bt corn tissues material. Decreasing susceptibility of O. furnacalis to Bt and to Bt corn were found in each selected strain although the ED50 and larval weight fluctuated from generation to generation. The resistance of Bt-exposed strain (RR-1) to Btk increased 48-fold by generation 39; the Bt corn-exposed strain (RR-2) increased its resistance 37-fold to Btk by generation 24. No larvae of SS-1 survived when they were exposed to the leaves of Bt corn, Bt11 and MON810. However, 2-54% of the RR-1 (generation 46) and RR-2 (generation 20) larvae survived a 3 day-exposure to the leaves of Bt11 and MON810. The survival of both selected strains on Bt corn silk increased by 10-69%, and the larval weights after many generations selection were increased by 15-22% compared with the unselected susceptible strain. The young larvae were much more susceptible to Bt than older larvae. The highest mortality occurred when the larvae were exposed to Bt at the neonate stage. All of the results suggested that ACB could not only develop resistance to Bt preparation but also to Bt corn. Bt had significant effects on the growth and development of Asian corn borer than on the larval mortality. In order to maintain the long-term effectiveness of Bt pesticide and Bt corn, the resistance management should pay much attention to the larvae that may have opportunities to grow and developed on non-Bt corn or alternate hosts before they attack the Bt corn plants and the survival of larvae after Bt application.
文摘The S-endotoxin genes of Bacillus thuringiensis (Bt) and proteinase inhibitor (PI) genes are two kinds of genes popularly used for developing transgenic plants resistant to insect pests. To clarify whether there is any risk concerning the effects of pollens from these transgenic crops on non-target insects with economic importance, such as the effects on the growth and development as well as cocoon quality of the silkworm, Bombyx mori Linnaeus, a series of feeding experiments were conducted, using pollens from transgenic cotton or corn containing cry 1Ac, cry1A+CpTI or crylAb genes, compared with pollens from non-transgenic normal cotton and corn as well as the non-pollen treatment. In contrast to the latter ones, pollens from transgenic plants showed no significant adverse effects on larval mortality, cocoon weight, pupa weight, cocoon shell weight, pupation rate, emergence rate and fecundity of the silkworm after neonates were fed with the pollens for 72 h. In addition, no dosage effects of pollens were found. Though the duration of 1st instar larvae was prolonged in the case of feeding with transgenic pollens as compared with those of the non-pollen treatment , but they were not significantly different from those fed with pollens from non-transgenic cotton or corn. Meanwhile, the body weight of the 3rd instar molters fed with transgenic pollens was obviously different from those for non-pollen treatment, and was all significantly heavier than that of the controls. Consequently, it is considered that the adverse effect of pollens from transgenic insect-resistant cotton and corn on the growth and development of the silkworm is negligible.
基金the Associate Vice President&Program Leader of the Louisiana State University Agricultural Center as Manuscript Number:2020-234-34549This study was sponsored by Hatch funds from the USDA National Institute of Food and Agriculture,and the USDA Multistate Research Project NC-246.
文摘The fall armyworm,Spodoptera frugiperda(J.E.Smith),is a major target pest of Bt crops(e.g.,corn,cotton,and soybean)in North and South America.This pest has recently invaded Africa and Asia including China and the invasion has placed a great threat to the food security in many countries of these two continents.Due to the extensive use of Bt crops,practical resistance of S.frugiperda to Cry IF corn(TC 1507)with field control problems has widely occurred in Puerto Rico,Brazil,Argentina,and the mainland United States.Analyzing data generated from decade-long studies showed that several factors might have contributed to the wide development of the resistance.These factors include(1)limited modes of action of Bt proteins used in Bt crops;(2)cross-resistance among Cryl proteins;(3)use of nonhigh dose Bt crop traits;(4)that the resistance is complete on Bt corn plants;(5)abundant in initial Cry IF resistance alleles;and(6)lack of fitness costs/recessive fitness costs of the resistance.The long-term use of Bt crop technology in the Americas suggests that Bt corn can be an effective tool for controlling S.frugiperda in China.IRM programs for Bt corn in China should be as simple as possible to be easily adopted by small-scale growers.The following aspects may be considered in its Bt corn IRM programs:(1)use of only"high dose^traits for both S.frugiperda and stalk borers;(2)developing and implementing a combined resistance monitoring program;(3)use“gene pyramiding”as a primary IRM strategy;and(4)if possible,Bt corn may not be planted in the areas where S.frugiperda overwinters.Lessons and experience gained from the global long-term use of Bt crops should have values in improving IRM programs in the Americas,as well as for a sustainable use of Bt corn technology in China.
基金the National Natural Science Foundation of China(30470335,30770402)Natural Science Foundation of Guangdong Province,China(E039254,06025813).
文摘Bt corn is one of the top three large-scale commercialized transgenic crops around the world. It is increasingly clear that the complementary durable approaches for pest control, which combine the endogenous defense of the crop with the introduced foreign genes, are promising alternative strategies for pest resistance management and the next generation of insect-resistant transgenic crops. In the present study, we tested the inducible effects of exogenous jasmonic acid （JA） on direct-defense chemical content, Bt protein concentration, and related gene expression in the leaves of Bt corn cultivar 34B24 and non-Bt cultivar 34B23 by chemical analysis, ELISA, and RT-PCR. The results show that the expression of LOX, PR-2a, MPI, and PR-I genes in the treated leaf （the first leaf） was promoted by exogenous JA both in 34B24 and 34B23. As compared with the control, the concentration of DIMBOA in the treated leaf was significantly increased by 63 and 18% for 34B24 and 34B23, respectively. The total phenolic acid was also increased by 24 and 12% for both 34B24 and 34B23. The Bt protein content of 34B24 in the treated leaf was increased by 13% but decreased significantly by 27% in the second leaf. The induced response of 34B24 was in a systemic way and was much stronger than that of 34B23. Those findings indicated that there is a synergistic interaction between Bt gene and internally induced chemical defense system triggered by externally applied JA in Bt corn.
文摘The research cxamined the effects of microbial and novel insecticidal control strategies and also Irichogramma pretiosum on the I,epidoptera： Crambidae, the European corn borer （ECB）, （Ostrinia nubilalis）. The treatments included ~ino^d, from bacteria the entomopathogenic fungus Beauveria bassiana, the egg parasitoid Trichogramma pretiosum, and foliar applied Bt spray, and t^vo combinations Bearveria bassiana plus Bt spray and Trichogramma pretiosum and spinosad. The infestations by the European corn borer larvae on stalks of corn were very＂ severe in all the control treatments both 2006 and 2007. The microbial treatments caused various levels of European corn borer mortality. In all the parameters there was a significant difference between the control and other treatments with a P 〈 0.00 l. In this research, treatment with spinosad emerged as the most effective biological agent in the control of the European corn borer. The treatments had no significant effects on the relative abundance and composition of non-target arthropods （P 〉 0.05）. This research is relevant in boosting underutilized control strategies and increasing stakeholder adoption of integrated pest management practices and thereby＇ reducing the use of conventional insecticides especially for orgamc thrmers. This is very important especially in certain countries where the commumities are skeptical about consuming transgenic crops.
文摘【目的】Bt(Bacillus thuringiensis)玉米(Zea may sL.)是全球商品化程度最快的抗虫转基因作物之一,协调利用其内在防御机制和人工导入抗性是目标害虫抗性风险综合管理和第2代抗虫转基因作物培育的主要策略之一。【方法】采用基因表达分析、化学物质分析和ELISA蛋白定量方法,研究外施信号物质茉莉酸对Bt玉米34B24(Mon810)及其同源常规玉米34B23幼苗叶片直接防御物质含量及其相关基因表达的影响。【结果】外源茉莉酸处理能诱导34B24和34B23处理叶(第1叶)中LOX、PR-2a、MPI和PR-1基因的表达,第1叶丁布含量分别比对照增加63%和18%、总酚含量分别增加24%和12%。茉莉酸处理使34B24第1叶中的Bt蛋白含量增加了13%,但第2叶中的显著降低了27%。与34B23相比,茉莉酸对34B24的诱导作用更强,并具有系统性。【结论】人工外施茉莉酸的条件下,Bt玉米人工导入抗性(Bt基因)和自身化学防御过程之间的互作关系是协同的。
