Expression of insecticidal protein for transgenic Bacillus thuringiensis （Bt） cotton is unstable and related to nitrogen metabolism. The objective of this study was to investigate the relationship between leaf carbo...Expression of insecticidal protein for transgenic Bacillus thuringiensis （Bt） cotton is unstable and related to nitrogen metabolism. The objective of this study was to investigate the relationship between leaf carbon nitrogen ratio （C/N） and insecticidal efficacy of two Bt cotton cultivars. C/N ratio and Bt protein content were both measured at peak square period and peak boll period respectively under 5-7 d high temperature and different nitrogen fertilizer rates on the Yangzhou University Farm and the Ludong Cotton Farm, China. All plants were grown in field. The results showed that the C/N ratio enhanced slightly and the Bt protein content remained stable at peak square period, but significant increases for the C/N ratio and decreases markedly for the leaf Bt protein concentration were detected at the peak boll period. The similar patterns at the two growth periods were found for the leaf C/N ratio and Bt protein content by different N fertilizer treatments. When nitrogen rate was from 0 to 600 kg ha-l, the C/N ratio was reduced by 0.017 and 0.006 for Sikang 1 and Sikang 3 at peak square period, compared to the 1.350 to 1.143 reduction for Sikang 1 and Sikang 3 at peak boll period, respectively. Correspondingly, the leaf Bt protein contents were bolstered by 2.6-11.8 and 26.9-36.9% at the two different growth periods, respectively. The results suggested that enhanced C/N ratio by high temperature and nitrogen application may result in the reduction of inseetiocidal efficacy in Bt cotton, especially in peak boll period.展开更多
To clarify the effect of the N deficit on the amount of square Bt insecticidal protein, different N application rates(0, 75, 150, 225, and 300 kg ha^–1) were imposed on the conventional cultivar Sikang 1(SK-1) and hy...To clarify the effect of the N deficit on the amount of square Bt insecticidal protein, different N application rates(0, 75, 150, 225, and 300 kg ha^–1) were imposed on the conventional cultivar Sikang 1(SK-1) and hybrid cultivar Sikang 3(SK-3) during 2015–2016 cotton growth seasons. Under different N application rates, the square number per plant, square volume and square dry weight reduced when the N rates decreased from conventional rate(300 kg ha^–1) to 0 kg ha^–1. And the square Bt protein content decreased accordingly. The analysis of N metabolism showed that soluble protein content, GPT and GOT activities decreased, free amino acid, peptidase and protease activities increased under N deficit. Correlation analysis indicated that the reduced Bt protein content under N deficit was related to altered N metabolism. In conclusion, square development and the amount of square Bt toxin both decreased under N deficit, indicating that promoting the square development under appropriate N application rate would also promote the insect resistance during squaring stage.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
We investigated the inheritance and expression of cry1A gene in transgenic maize ( Zea mays L.) by Southern blotting analysis and enzyme_linked immunosorbent assays (ELISA). The results showed that cry1A ha...We investigated the inheritance and expression of cry1A gene in transgenic maize ( Zea mays L.) by Southern blotting analysis and enzyme_linked immunosorbent assays (ELISA). The results showed that cry1A had been transmitted to progeny of transgenic maize as a single gene. Contents of cry1A insecticidal protein were significantly different among transgenic maize lines and various tissues of the same transgenic lines. High expression of cry1A protein occurred in green tissues, such as leaf and husk leaf, and low expression occurred in pith, tassel, ear pith, pollen and silk. The results also showed that the contents of cry1A insecticidal protein in leaves of transgenic maize increased with the advance of development and there was no significant difference in cry1A expression level among various generations of transgenic maize.展开更多
Microbially derived,protein-based biopesticides have become a vital element in pest management strategies.Vip3 family proteins from Bacillus thuringiensis have distinct characteristics from known insecticidal Cry toxi...Microbially derived,protein-based biopesticides have become a vital element in pest management strategies.Vip3 family proteins from Bacillus thuringiensis have distinct characteristics from known insecticidal Cry toxins and show efficient insecticidal activity against several detrimental lepidopteran pests.They are considered to be a promising toxic candidate for the management of various detrimental pests.In this study,we found that in addition to the preliminary digestion sites lysine,there are multiple cleavage activation sites in the linker region between domain I(DI)and DII of Vip3Aa.We further demonstrated that by adding more cleavage sites between DI and DII of Vip3Aa,its proteolysis efficiency by midgut proteases can be significantly increased,and correspondingly enhance its insecticidal activity against Spodoptera frugiperda and Helicoverpa armigera larvae.Our study promotes the understanding of the insecticidal mechanism of Vip3 proteins and illustrates an eas-ily implementable strategy to increase the insecticidal potency of Vip3Aa.This facilitates their potential future development and efficient application for sustainable agriculture.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(31171479)the Key Laboratory Foundation of Jiangsu Province,China(10KJA210057)+2 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions,China,the Doctoral Advisor Foundation of Education Department of China(20113250110001)the Project of National Agricultural Modern Industrial Technology System Post Experts,China(CARS-18-20)the Graduate Student Scientific Research Innovation Projects of Jiangsu Province,China(CXLX11_1019)
文摘Expression of insecticidal protein for transgenic Bacillus thuringiensis （Bt） cotton is unstable and related to nitrogen metabolism. The objective of this study was to investigate the relationship between leaf carbon nitrogen ratio （C/N） and insecticidal efficacy of two Bt cotton cultivars. C/N ratio and Bt protein content were both measured at peak square period and peak boll period respectively under 5-7 d high temperature and different nitrogen fertilizer rates on the Yangzhou University Farm and the Ludong Cotton Farm, China. All plants were grown in field. The results showed that the C/N ratio enhanced slightly and the Bt protein content remained stable at peak square period, but significant increases for the C/N ratio and decreases markedly for the leaf Bt protein concentration were detected at the peak boll period. The similar patterns at the two growth periods were found for the leaf C/N ratio and Bt protein content by different N fertilizer treatments. When nitrogen rate was from 0 to 600 kg ha-l, the C/N ratio was reduced by 0.017 and 0.006 for Sikang 1 and Sikang 3 at peak square period, compared to the 1.350 to 1.143 reduction for Sikang 1 and Sikang 3 at peak boll period, respectively. Correspondingly, the leaf Bt protein contents were bolstered by 2.6-11.8 and 26.9-36.9% at the two different growth periods, respectively. The results suggested that enhanced C/N ratio by high temperature and nitrogen application may result in the reduction of inseetiocidal efficacy in Bt cotton, especially in peak boll period.
基金supported by the National Natural Science Foundation of China (31901462 and 31671613)the National Key Research and Development Program of China (2018YFD0100406 and 2018YFD1000907)+1 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions,China (18KJB210013 and 17KJA210003)the Natural Science Foundation of Jiangsu Province,China (BK20191439)。
文摘To clarify the effect of the N deficit on the amount of square Bt insecticidal protein, different N application rates(0, 75, 150, 225, and 300 kg ha^–1) were imposed on the conventional cultivar Sikang 1(SK-1) and hybrid cultivar Sikang 3(SK-3) during 2015–2016 cotton growth seasons. Under different N application rates, the square number per plant, square volume and square dry weight reduced when the N rates decreased from conventional rate(300 kg ha^–1) to 0 kg ha^–1. And the square Bt protein content decreased accordingly. The analysis of N metabolism showed that soluble protein content, GPT and GOT activities decreased, free amino acid, peptidase and protease activities increased under N deficit. Correlation analysis indicated that the reduced Bt protein content under N deficit was related to altered N metabolism. In conclusion, square development and the amount of square Bt toxin both decreased under N deficit, indicating that promoting the square development under appropriate N application rate would also promote the insect resistance during squaring stage.
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.
文摘We investigated the inheritance and expression of cry1A gene in transgenic maize ( Zea mays L.) by Southern blotting analysis and enzyme_linked immunosorbent assays (ELISA). The results showed that cry1A had been transmitted to progeny of transgenic maize as a single gene. Contents of cry1A insecticidal protein were significantly different among transgenic maize lines and various tissues of the same transgenic lines. High expression of cry1A protein occurred in green tissues, such as leaf and husk leaf, and low expression occurred in pith, tassel, ear pith, pollen and silk. The results also showed that the contents of cry1A insecticidal protein in leaves of transgenic maize increased with the advance of development and there was no significant difference in cry1A expression level among various generations of transgenic maize.
基金supported by the National Natural Science Foundation of China(3190194332122007,and 32272610)the Shandong Provincial Natural Science Foundation(ZR2021JQ09)+3 种基金the Major Basic Program of Natural Science Foundation of Shandong Province(ZR2019ZD21)the Key R&D Program of Shandong Province(2020CXGC011305)the Youth Interdisciplinary Innovative Research Group of Shandong Univer-sity(2020QNQT009)the China Postdoctoral Science Foundation funded project(2019T120585 and 2019M652370).
文摘Microbially derived,protein-based biopesticides have become a vital element in pest management strategies.Vip3 family proteins from Bacillus thuringiensis have distinct characteristics from known insecticidal Cry toxins and show efficient insecticidal activity against several detrimental lepidopteran pests.They are considered to be a promising toxic candidate for the management of various detrimental pests.In this study,we found that in addition to the preliminary digestion sites lysine,there are multiple cleavage activation sites in the linker region between domain I(DI)and DII of Vip3Aa.We further demonstrated that by adding more cleavage sites between DI and DII of Vip3Aa,its proteolysis efficiency by midgut proteases can be significantly increased,and correspondingly enhance its insecticidal activity against Spodoptera frugiperda and Helicoverpa armigera larvae.Our study promotes the understanding of the insecticidal mechanism of Vip3 proteins and illustrates an eas-ily implementable strategy to increase the insecticidal potency of Vip3Aa.This facilitates their potential future development and efficient application for sustainable agriculture.
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.
