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
[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
[Objective] The aim of this study was to study on expression of Bt protein in transgenic pest-resistant rice. [Method] Enzyme-linked immunosorbent assay （ELISA） was used to measure Bt protein expression in different...[Objective] The aim of this study was to study on expression of Bt protein in transgenic pest-resistant rice. [Method] Enzyme-linked immunosorbent assay （ELISA） was used to measure Bt protein expression in different tissues of transgenic pest-resistant rice at same growth stage. [Result] Absolute content of Bt protein from high to low was as follows： leaves 〉 immature seeds and glumes 〉 roots 〉 stems in different tissues of transgenic rice in grain-filling stage; Bt protein content of trans- genic rice changed a little in different growth stages （including tillering stage, booting stage, and grain-filling stage）; in general, its level declined a little in later growth stage, but the resistibility would not be influenced significantly. [Conclusion] The ex- periment is significant for pest prevention and transgenic rice breeding.展开更多
Higher boll worm survival rates were detected after high temperature presented during square period in Bt cotton. The objective of this study was to investigate the effects of high temperature level on the Bt efficacy...Higher boll worm survival rates were detected after high temperature presented during square period in Bt cotton. The objective of this study was to investigate the effects of high temperature level on the Bt efficacy of two different types of Bt cotton cultivars at squaring stage. During the 2011 to 2013 cotton growth seasons, high temperature treatments ranged from 34 to 44°C in climate chambers, and field experiments under high temperature weather with various temperature levels were conducted to investigate the effects of the high temperature level on square Bt protein concentration and nitrogen metabolism. The climate chamber experiments showed that the square insecticidal protein contents reduced after 24 h elevated temperature treatments for both cultivars, whereas significant declines of the square insecticidal protein contents were detected at temperature 〉38°C, and only slightly numerical reductions were observed when temperature below 38°C. Similar high temperature responses were also observed at the two field experimental sites in 2013. Correspondingly, high temperature below 38°C seems have little effect on the square amino acid concentrations, soluble protein contents, glutamic-pyruvic transaminase（GPT） and glutamic-oxalacetic transaminase（GOT） activities as well as protease and peptidase activities; however, when the temperature was above 38°C, reduced soluble protein contents, enhanced amino acid concentrations, decreased GPT and GOT activities, bolstered protease and peptidase activities in square were detected. In general, the higher the temperature is（〉38°C）, the larger the changes for the above compound contents and key enzymes activities of the square protein cycle. The findings indicated that the unstable insect resistance of the square was related to high temperature level during square stage.展开更多
[Objective] The paper was to study the temporal and spatial dynamics of Bt protein expression in transgenic Bt cotton and to determine the inner relationship of Bt protein expression and transgenic Bt cotton. [Method]...[Objective] The paper was to study the temporal and spatial dynamics of Bt protein expression in transgenic Bt cotton and to determine the inner relationship of Bt protein expression and transgenic Bt cotton. [Method] With transgenic cotton cultivar（ GK19） as the test material,Bt protein contents in different organs,main stem functional leaves at different growth stages and different positions of main stem leaves at different growth stages were studied by enzyme-linked immunosorbent assay. [Result] There were differences in Bt protein content among different organs of transgenic Bt cotton; the Bt protein content of leaves at seedling stage was the highest,followed by flowers,bubs and bolls,and those of roots and stems were relatively low. The Bt protein content of main stem function leaves gradually decreased with the progressing development. There were great differences in Bt protein content among different positions of main stem leaves at different growth stages; the Bt protein content of the 1^（st）-7^（th） top leaves at seedling stage and full budding stage gradually decreased,while those at full flowering stage and full bolling stage first slowly increased then gradually stabilized. [Conclusion] Bt protein expression was found in all organs of transgenic cotton at all growth stages,and the expression level presented temporal and spatial dynamics.展开更多
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
[Objective] This study aimed to investigate the spatial-temporal dynamics of Bt toxic protein expression in insect-resistant transgenic cotton and its degradation in soil. [Method] Btcry1Ac toxic protein expression in...[Objective] This study aimed to investigate the spatial-temporal dynamics of Bt toxic protein expression in insect-resistant transgenic cotton and its degradation in soil. [Method] Btcry1Ac toxic protein expression in roots, stems and leaves of transgenic cotton Guoshen GK45 at different developmental stages and the annual average content of BtCry1Ac toxin protein in the topsoil, rhizosphere soil and following cotton-growing area were explored and analyzed by using enzyme linked immuno sorbed assay (ELISA). [Result] The content of exogenous BtCry1Ac toxin protein decreased during the growth process of insect-resistant transgenic cotton; to be specific, the content of BtCry1Ac toxin protein in cotton stems and leaves decreased more slowly and always maintained a high level, while that in roots decreased rapidly and reached a minimum level to the following plant growth and development stage. BtCry1Ac toxin protein was detected in topsoil of both non-transgenic and transgenic cotton-growing areas, and the content of BtCry1Ac toxin protein increased in topsoil of following cotton-growing area, which was very low in rhizosphere soil. [Conclusion] Determination of Btcry1Ac toxic protein provides scientific basis for the risk assessment of the cultivation of genetically modified crops and the safety evaluation of soil ecosystem.展开更多
Background:Low insecticidal protein expression at reproductive organs affect insect resistance in Bt transgenic cotton.In order to enhance flower insecticidal protein expression,the conventional cultivar Sikang1(S1)an...Background:Low insecticidal protein expression at reproductive organs affect insect resistance in Bt transgenic cotton.In order to enhance flower insecticidal protein expression,the conventional cultivar Sikang1(S1)and the hybrid cultivar Sikang3(S3)were used as experimental materials;the applications of selected 5 types of amino acids and 21 types of amino acids were sprayed on the flowers in 2016 and 2017 cotton growing seasons.Results:The flower Bt protein contents increased significantly under the two amino acid treatments in both cultivars,the Bt protein concentration increased by 15.2 to 25.8%compared with the control.However,no significant differences were detected between the two treatments of amino acid application.Increased amino acid and soluble protein contents,enhanced GPT,GOT,protease,and peptidase activities were observed under the amino acid application at the flowering stage.Conclusions:These results suggest that exterior application of the amino acids treatments could bolster the flower insecticidal protein expression.展开更多
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, ...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.展开更多
This study was conducted to investigate the effects of alternating high temperature on CrylAc protein content on Bt cotton cultivars Sikang 1 （SK-1, a conventional cultivar） and Sikang 3 （SK-3, a hybrid cultivar）....This study was conducted to investigate the effects of alternating high temperature on CrylAc protein content on Bt cotton cultivars Sikang 1 （SK-1, a conventional cultivar） and Sikang 3 （SK-3, a hybrid cultivar）. In 2011 and 2012, cotton plants were subjected to high temperature treatments ranging from 32 to 40℃ in climate chambers to investigate the effects of high temperature on boll shell insecticidal protein expression. The experiments showed that significant decline of the boll shell insecticidal protein was detected at temperatures higher than 38℃ after 24 h. Based on the results, the cotton plants were treated with the threshold temperature of 38℃ from 6：00 a.m. to 6：00 p.m. followed by a normal temperature of 27℃ during the remaining night hours （DH/NN） in 2012 and 2013. These treatments were conducted at peak boll growth stage for both cultivars in study periods of 0, 4, 7, and 10 d. Temperature treatment of 32℃ from 6：00 a.m. to 6：00 p.m. and 27℃ in the remaining hours was set as control. The results showed that, compared with the control, after the DH/NN stress treatment applied for 7 d, the boll shell CrylAc protein content level was significantly decreased by 19.1 and 17.5% for SK-1 and by 15.3 and 13.7% for SK-3 in 2012 and 2013, respectively. Further analysis of nitrogen metabolic physiology under DH/NN showed that the soluble protein content and the glutamic pyruvic transaminase （GPT） activities decreased slightly after 4 d, and then decreased sharply after 7 d. The free amino acid content and the protease content increased sharply after 7 d. The changes in SK-1 were greater than those in SK-3. These results suggest that under DH/NN stress, boll shell CrylAc protein content decline was delayed. Reduced protein synthesis and increased protein degradation in the boll shell decreased protein content, including Bt protein, which may reduce resistance to the cotton bollworm.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.
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.
基金Transgenic cry1C Novel Materials of Japonica Rice Resistant Against Snout Moth’s Larva Cultivated with Biotechnology (201205068)The National Program of Transgenic Variety Development of China (2011ZX08001-001)~~
文摘[Objective] The aim of this study was to study on expression of Bt protein in transgenic pest-resistant rice. [Method] Enzyme-linked immunosorbent assay （ELISA） was used to measure Bt protein expression in different tissues of transgenic pest-resistant rice at same growth stage. [Result] Absolute content of Bt protein from high to low was as follows： leaves 〉 immature seeds and glumes 〉 roots 〉 stems in different tissues of transgenic rice in grain-filling stage; Bt protein content of trans- genic rice changed a little in different growth stages （including tillering stage, booting stage, and grain-filling stage）; in general, its level declined a little in later growth stage, but the resistibility would not be influenced significantly. [Conclusion] The ex- periment is significant for pest prevention and transgenic rice breeding.
基金supported by the National Natural Science Foundation of China (31171479, 31301263 and 31471435)the Doctoral Advisor Foundation of Ministry of Education of China (20113250110001)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions, China (PAPD)the Three New Technology Foundation of Agriculture in Jiangsu Province, China (SXGC(2014)317)
文摘Higher boll worm survival rates were detected after high temperature presented during square period in Bt cotton. The objective of this study was to investigate the effects of high temperature level on the Bt efficacy of two different types of Bt cotton cultivars at squaring stage. During the 2011 to 2013 cotton growth seasons, high temperature treatments ranged from 34 to 44°C in climate chambers, and field experiments under high temperature weather with various temperature levels were conducted to investigate the effects of the high temperature level on square Bt protein concentration and nitrogen metabolism. The climate chamber experiments showed that the square insecticidal protein contents reduced after 24 h elevated temperature treatments for both cultivars, whereas significant declines of the square insecticidal protein contents were detected at temperature 〉38°C, and only slightly numerical reductions were observed when temperature below 38°C. Similar high temperature responses were also observed at the two field experimental sites in 2013. Correspondingly, high temperature below 38°C seems have little effect on the square amino acid concentrations, soluble protein contents, glutamic-pyruvic transaminase（GPT） and glutamic-oxalacetic transaminase（GOT） activities as well as protease and peptidase activities; however, when the temperature was above 38°C, reduced soluble protein contents, enhanced amino acid concentrations, decreased GPT and GOT activities, bolstered protease and peptidase activities in square were detected. In general, the higher the temperature is（〉38°C）, the larger the changes for the above compound contents and key enzymes activities of the square protein cycle. The findings indicated that the unstable insect resistance of the square was related to high temperature level during square stage.
基金Supported by Genetic Engineering Project of Sichuan Province(2014LWJJ-011)
文摘[Objective] The paper was to study the temporal and spatial dynamics of Bt protein expression in transgenic Bt cotton and to determine the inner relationship of Bt protein expression and transgenic Bt cotton. [Method] With transgenic cotton cultivar（ GK19） as the test material,Bt protein contents in different organs,main stem functional leaves at different growth stages and different positions of main stem leaves at different growth stages were studied by enzyme-linked immunosorbent assay. [Result] There were differences in Bt protein content among different organs of transgenic Bt cotton; the Bt protein content of leaves at seedling stage was the highest,followed by flowers,bubs and bolls,and those of roots and stems were relatively low. The Bt protein content of main stem function leaves gradually decreased with the progressing development. There were great differences in Bt protein content among different positions of main stem leaves at different growth stages; the Bt protein content of the 1^（st）-7^（th） top leaves at seedling stage and full budding stage gradually decreased,while those at full flowering stage and full bolling stage first slowly increased then gradually stabilized. [Conclusion] Bt protein expression was found in all organs of transgenic cotton at all growth stages,and the expression level presented temporal and spatial dynamics.
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.
文摘[Objective] This study aimed to investigate the spatial-temporal dynamics of Bt toxic protein expression in insect-resistant transgenic cotton and its degradation in soil. [Method] Btcry1Ac toxic protein expression in roots, stems and leaves of transgenic cotton Guoshen GK45 at different developmental stages and the annual average content of BtCry1Ac toxin protein in the topsoil, rhizosphere soil and following cotton-growing area were explored and analyzed by using enzyme linked immuno sorbed assay (ELISA). [Result] The content of exogenous BtCry1Ac toxin protein decreased during the growth process of insect-resistant transgenic cotton; to be specific, the content of BtCry1Ac toxin protein in cotton stems and leaves decreased more slowly and always maintained a high level, while that in roots decreased rapidly and reached a minimum level to the following plant growth and development stage. BtCry1Ac toxin protein was detected in topsoil of both non-transgenic and transgenic cotton-growing areas, and the content of BtCry1Ac toxin protein increased in topsoil of following cotton-growing area, which was very low in rhizosphere soil. [Conclusion] Determination of Btcry1Ac toxic protein provides scientific basis for the risk assessment of the cultivation of genetically modified crops and the safety evaluation of soil ecosystem.
基金The Projects#2017YFD0201306,#2018YFD0100406 supported by the National Key R&D Program of China#31671613 supported by National Natural Science Foundation of China+1 种基金Project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China(PAPD)Project#2016PCTS-1 supported by the Chinese academy of agricultural sciences’engineering science and technology innovation fund
文摘Background:Low insecticidal protein expression at reproductive organs affect insect resistance in Bt transgenic cotton.In order to enhance flower insecticidal protein expression,the conventional cultivar Sikang1(S1)and the hybrid cultivar Sikang3(S3)were used as experimental materials;the applications of selected 5 types of amino acids and 21 types of amino acids were sprayed on the flowers in 2016 and 2017 cotton growing seasons.Results:The flower Bt protein contents increased significantly under the two amino acid treatments in both cultivars,the Bt protein concentration increased by 15.2 to 25.8%compared with the control.However,no significant differences were detected between the two treatments of amino acid application.Increased amino acid and soluble protein contents,enhanced GPT,GOT,protease,and peptidase activities were observed under the amino acid application at the flowering stage.Conclusions:These results suggest that exterior application of the amino acids treatments could bolster the flower insecticidal protein expression.
基金This study was financially supported by the National Natural Science Foundation of China （30070500） to Cheng Jiaan.
文摘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.
基金supported by the National Natural Science Foundation of China(31471435,31671613,and 31301263)the China Postdoctoral Science Foundation Grant(2016M591934)+3 种基金the Postdoctoral Science Foundation Grant in Jiangsu Province,China(1601116C)the Key Projects of Natural Science Research in Colleges and Universities of Jiangsu,China(17KJA210003)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China(PAPD)the Practice Innovation Training Project for College Students in Jiangsu Province,China
文摘This study was conducted to investigate the effects of alternating high temperature on CrylAc protein content on Bt cotton cultivars Sikang 1 （SK-1, a conventional cultivar） and Sikang 3 （SK-3, a hybrid cultivar）. In 2011 and 2012, cotton plants were subjected to high temperature treatments ranging from 32 to 40℃ in climate chambers to investigate the effects of high temperature on boll shell insecticidal protein expression. The experiments showed that significant decline of the boll shell insecticidal protein was detected at temperatures higher than 38℃ after 24 h. Based on the results, the cotton plants were treated with the threshold temperature of 38℃ from 6：00 a.m. to 6：00 p.m. followed by a normal temperature of 27℃ during the remaining night hours （DH/NN） in 2012 and 2013. These treatments were conducted at peak boll growth stage for both cultivars in study periods of 0, 4, 7, and 10 d. Temperature treatment of 32℃ from 6：00 a.m. to 6：00 p.m. and 27℃ in the remaining hours was set as control. The results showed that, compared with the control, after the DH/NN stress treatment applied for 7 d, the boll shell CrylAc protein content level was significantly decreased by 19.1 and 17.5% for SK-1 and by 15.3 and 13.7% for SK-3 in 2012 and 2013, respectively. Further analysis of nitrogen metabolic physiology under DH/NN showed that the soluble protein content and the glutamic pyruvic transaminase （GPT） activities decreased slightly after 4 d, and then decreased sharply after 7 d. The free amino acid content and the protease content increased sharply after 7 d. The changes in SK-1 were greater than those in SK-3. These results suggest that under DH/NN stress, boll shell CrylAc protein content decline was delayed. Reduced protein synthesis and increased protein degradation in the boll shell decreased protein content, including Bt protein, which may reduce resistance to the cotton bollworm.
