Bacillus thuringiensis(Bt)cotton production is challenged by two main problems,i.e.,the low concentration of Bt protein at the boll setting stage and the lowest insect resistance in bolls among all the cotton plant’s...Bacillus thuringiensis(Bt)cotton production is challenged by two main problems,i.e.,the low concentration of Bt protein at the boll setting stage and the lowest insect resistance in bolls among all the cotton plant’s organs.Therefore,increasing the Bt protein concentration at the boll stage,especially in bolls,has become the main goal for increasing insect resistance in cotton.In this study,two protein degradation inhibitors(ethylene diamine tetra acetic acid(EDTA)and leupeptin)were sprayed on the bolls,subtending leaves,and whole cotton plants at the peak flowering stage of two Bt cultivars(medium maturation Sikang 1(SK1))and early maturation Zhongmian 425(ZM425)in 2019 and 2020.The Bt protein content and protein degradation metabolism were assessed.The results showed that the Bt protein concentrations were enhanced by 21.3 to 38.8%and 25.0 to 38.6%in the treated bolls of SK1 and ZM425 respectively,while they were decreased in the subtending leaves of these treated bolls.In the treated leaves,the Bt protein concentrations increased by 7.6 to 23.5%and 11.2 to 14.9%in SK1 and ZM425,respectively.The combined application of EDTA and leupeptin to the whole cotton plant increased the Bt protein concentrations in both bolls and subtending leaves.The Bt protein concentrations in bolls were higher,increasing by 22.5 to 31.0%and 19.6 to 32.5%for SK1 and ZM425,respectively.The organs treated with EDTA or/and leupeptin showed reduced free amino acid contents,protease and peptidase activities and significant enhancements in soluble protein contents.These results indicated that inhibiting protein degradation could improve the protein content,thus increasing the Bt protein concentrations in the bolls or/and leaves of cotton plants.Therefore,the increase in the Bt protein concentration without yield reduction suggested that these two protein degradation inhibitors may be applicable for improving insect resistance in cotton production.展开更多
During the boll formation stage,cotton bolls exhibit the lowest expression of Bacillus thuringiensis(Bt)insecticidal proteins.Resistance to insects varies notably among different organs,which poses challenges for cont...During the boll formation stage,cotton bolls exhibit the lowest expression of Bacillus thuringiensis(Bt)insecticidal proteins.Resistance to insects varies notably among different organs,which poses challenges for controlling cotton bollworms.Consequently,an experimental strategy was designed in the 2020-2021 cotton growing season to coordinate the enhancement of protein synthesis and the attenuation of degradation.Two Bt cultivars of Gossypium hirsutum,namely the hybrid Sikang 3 and the conventional Sikang 1,were used as test materials.Three treatments were applied at the peak flowering period:CK(the control),T1(amino acids),and T2(amino acids and EDTA).The results show that,in comparison to the CK group,the Bt protein contents were significantly increased in both cotton bolls and their subtending leaves under the T1 and T2 treatments.The maximum levels of increase observed were 67.5%in cotton bolls and 21.7%in leaves.Moreover,the disparity in Bt protein content between cotton bolls and their subtending leaves notably decreased by 31.2%.Correlation analysis suggested that the primary physiological mechanisms for augmenting Bt protein content involve increased protein synthesis and reduced protein catabolism,which are independent of Bt gene expression levels.Stepwise regression and path analysis revealed that elevating the soluble protein content and transaminase activity,while reducing the catabolic enzyme activities,are instrumental in enhancing the Bt protein content.Consequently,the coordinated application of amino acids and EDTA emerges as a strategy that can improve the overall resistance of Bt cotton and mitigate the spatiotemporal variations in Bt toxin concentrations in both cotton bolls and leaves.展开更多
Bacillus thuringiensis Berliner(Bt)cotton was widely grown in China from 1997.Since then,it has resulted in many misunderstandings and concerns about Bt cotton.However,extensive research and practical experience over ...Bacillus thuringiensis Berliner(Bt)cotton was widely grown in China from 1997.Since then,it has resulted in many misunderstandings and concerns about Bt cotton.However,extensive research and practical experience over the past 28 years in China have led to the resolution of many of these concerns.This short review explores how the concerns has been resolved,and provides valuable insights for the future utilization of genetically modified products.展开更多
[Objectives]To determine the biological safety of BT protein from Bacillus thuringiensis(Bt)fermentation broth to mammals at high doses.[Methods]Healthy mice were randomly divided into 4 groups with 10 mice in each gr...[Objectives]To determine the biological safety of BT protein from Bacillus thuringiensis(Bt)fermentation broth to mammals at high doses.[Methods]Healthy mice were randomly divided into 4 groups with 10 mice in each group.The experimental groups were fed with Bt fermentation supernatant at 0.2,0.6 and 1.0 mL/kg,respectively,once a day for 7 consecutive days.The blank control group was fed normally without intragastric administration.[Results]There was no significant difference in blood routine and blood biochemical analysis between the experimental group and the control group.After intragastric administration,the mice were dissected,and no obvious pathological changes were found;the heart,liver,spleen,lung and kidney were taken to make tissue sections,and no pathological changes were found by microscopic observation.[Conclusions]Mice can tolerate high doses of BT protein from B.thuringiensis fermentation broth.展开更多
Cotton plays a crucial role in shaping Indian economy and rural livelihoods.The cotton crop is prone to numerous insect pests,necessitating insecticidal application,which increases production costs.The advent of the e...Cotton plays a crucial role in shaping Indian economy and rural livelihoods.The cotton crop is prone to numerous insect pests,necessitating insecticidal application,which increases production costs.The advent of the expression of Bacillus thuringiensis(Bt)insecticidal protein in cotton has significantly reduced the burden of pest without compromising environmental or human health.After the introduction of transgenic cotton,the cultivated area expanded to 22 million hectares,with a 64% increase in adoption by farmers worldwide.Currently,Bt cotton accounts for 93% of the cultivated cotton area in India.However,extensive use of Bt cotton has accelerated resistance development in pests like the pink bollworm.Furthermore,the overreliance on Bt cotton has reduced the use of broad-spectrum pesticides,favouring the emergence of secondary pests with significant challenges.This emphasizes the urgent necessity for developing novel pest management strategies.The high-dose and refuge strategy was initially effective for managing pest resistance in Bt cotton,but its implementation in India faced challenges due to misunderstandings about the use of non-Bt refuge crops.Although gene pyramiding was introduced as a solution,combining mono toxin also led to instances of cross-resistance.Therefore,there is a need for further exploration of biotechnological approaches to manage insect resistance in Bt cotton.Advanced biotechnological strategies,such as sterile insect release,RNA interference(RNAi)-mediated gene silencing,stacking Bt with RNAi,and genome editing using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein(CRISPR-Cas),offer promising tools for identifying and managing resistance genes in insects.Additionally,CRISPR-mediated gene drives and the development of novel biopesticides present potential avenues for effective pest management in cotton cultivation.These innovative approaches could significantly enhance the sustainability and efficacy of pest resistance management in Bt cotton.展开更多
基金supported by the National Natural Science Foundation of China (31901462 and 31671613).
文摘Bacillus thuringiensis(Bt)cotton production is challenged by two main problems,i.e.,the low concentration of Bt protein at the boll setting stage and the lowest insect resistance in bolls among all the cotton plant’s organs.Therefore,increasing the Bt protein concentration at the boll stage,especially in bolls,has become the main goal for increasing insect resistance in cotton.In this study,two protein degradation inhibitors(ethylene diamine tetra acetic acid(EDTA)and leupeptin)were sprayed on the bolls,subtending leaves,and whole cotton plants at the peak flowering stage of two Bt cultivars(medium maturation Sikang 1(SK1))and early maturation Zhongmian 425(ZM425)in 2019 and 2020.The Bt protein content and protein degradation metabolism were assessed.The results showed that the Bt protein concentrations were enhanced by 21.3 to 38.8%and 25.0 to 38.6%in the treated bolls of SK1 and ZM425 respectively,while they were decreased in the subtending leaves of these treated bolls.In the treated leaves,the Bt protein concentrations increased by 7.6 to 23.5%and 11.2 to 14.9%in SK1 and ZM425,respectively.The combined application of EDTA and leupeptin to the whole cotton plant increased the Bt protein concentrations in both bolls and subtending leaves.The Bt protein concentrations in bolls were higher,increasing by 22.5 to 31.0%and 19.6 to 32.5%for SK1 and ZM425,respectively.The organs treated with EDTA or/and leupeptin showed reduced free amino acid contents,protease and peptidase activities and significant enhancements in soluble protein contents.These results indicated that inhibiting protein degradation could improve the protein content,thus increasing the Bt protein concentrations in the bolls or/and leaves of cotton plants.Therefore,the increase in the Bt protein concentration without yield reduction suggested that these two protein degradation inhibitors may be applicable for improving insect resistance in cotton production.
基金supported by the National Natural Science Foundation of China(31901462 and 31671613)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(22KJA210005)+1 种基金the China Scholarship Council(202308320440)the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(KYCX22_3508)。
文摘During the boll formation stage,cotton bolls exhibit the lowest expression of Bacillus thuringiensis(Bt)insecticidal proteins.Resistance to insects varies notably among different organs,which poses challenges for controlling cotton bollworms.Consequently,an experimental strategy was designed in the 2020-2021 cotton growing season to coordinate the enhancement of protein synthesis and the attenuation of degradation.Two Bt cultivars of Gossypium hirsutum,namely the hybrid Sikang 3 and the conventional Sikang 1,were used as test materials.Three treatments were applied at the peak flowering period:CK(the control),T1(amino acids),and T2(amino acids and EDTA).The results show that,in comparison to the CK group,the Bt protein contents were significantly increased in both cotton bolls and their subtending leaves under the T1 and T2 treatments.The maximum levels of increase observed were 67.5%in cotton bolls and 21.7%in leaves.Moreover,the disparity in Bt protein content between cotton bolls and their subtending leaves notably decreased by 31.2%.Correlation analysis suggested that the primary physiological mechanisms for augmenting Bt protein content involve increased protein synthesis and reduced protein catabolism,which are independent of Bt gene expression levels.Stepwise regression and path analysis revealed that elevating the soluble protein content and transaminase activity,while reducing the catabolic enzyme activities,are instrumental in enhancing the Bt protein content.Consequently,the coordinated application of amino acids and EDTA emerges as a strategy that can improve the overall resistance of Bt cotton and mitigate the spatiotemporal variations in Bt toxin concentrations in both cotton bolls and leaves.
基金National Natural Science Foundation of China(32372229)。
文摘Bacillus thuringiensis Berliner(Bt)cotton was widely grown in China from 1997.Since then,it has resulted in many misunderstandings and concerns about Bt cotton.However,extensive research and practical experience over the past 28 years in China have led to the resolution of many of these concerns.This short review explores how the concerns has been resolved,and provides valuable insights for the future utilization of genetically modified products.
文摘[Objectives]To determine the biological safety of BT protein from Bacillus thuringiensis(Bt)fermentation broth to mammals at high doses.[Methods]Healthy mice were randomly divided into 4 groups with 10 mice in each group.The experimental groups were fed with Bt fermentation supernatant at 0.2,0.6 and 1.0 mL/kg,respectively,once a day for 7 consecutive days.The blank control group was fed normally without intragastric administration.[Results]There was no significant difference in blood routine and blood biochemical analysis between the experimental group and the control group.After intragastric administration,the mice were dissected,and no obvious pathological changes were found;the heart,liver,spleen,lung and kidney were taken to make tissue sections,and no pathological changes were found by microscopic observation.[Conclusions]Mice can tolerate high doses of BT protein from B.thuringiensis fermentation broth.
文摘Cotton plays a crucial role in shaping Indian economy and rural livelihoods.The cotton crop is prone to numerous insect pests,necessitating insecticidal application,which increases production costs.The advent of the expression of Bacillus thuringiensis(Bt)insecticidal protein in cotton has significantly reduced the burden of pest without compromising environmental or human health.After the introduction of transgenic cotton,the cultivated area expanded to 22 million hectares,with a 64% increase in adoption by farmers worldwide.Currently,Bt cotton accounts for 93% of the cultivated cotton area in India.However,extensive use of Bt cotton has accelerated resistance development in pests like the pink bollworm.Furthermore,the overreliance on Bt cotton has reduced the use of broad-spectrum pesticides,favouring the emergence of secondary pests with significant challenges.This emphasizes the urgent necessity for developing novel pest management strategies.The high-dose and refuge strategy was initially effective for managing pest resistance in Bt cotton,but its implementation in India faced challenges due to misunderstandings about the use of non-Bt refuge crops.Although gene pyramiding was introduced as a solution,combining mono toxin also led to instances of cross-resistance.Therefore,there is a need for further exploration of biotechnological approaches to manage insect resistance in Bt cotton.Advanced biotechnological strategies,such as sterile insect release,RNA interference(RNAi)-mediated gene silencing,stacking Bt with RNAi,and genome editing using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein(CRISPR-Cas),offer promising tools for identifying and managing resistance genes in insects.Additionally,CRISPR-mediated gene drives and the development of novel biopesticides present potential avenues for effective pest management in cotton cultivation.These innovative approaches could significantly enhance the sustainability and efficacy of pest resistance management in Bt cotton.
