Application of virus-free sweetpotato is a breakthrough of sweetpotato production. Several popular varieties were adopted to study their yield increase potential and their use in breeding in this research. The results...Application of virus-free sweetpotato is a breakthrough of sweetpotato production. Several popular varieties were adopted to study their yield increase potential and their use in breeding in this research. The results showed that after virus-elimination, all varieties had a yield increase ranging from 14.95% - 91. 61% and marketable quality improvement, despite the changes in location and season. The changes of dry matter content and disease resistance were not significant. Virus-free sweetpotato performed vigorous vine growth and strong dry matter assimilation ability. Virus-free parents had a slightly high seed setting percentage, but its flowering ability and performance of off-springs were similar to that of its check plants.展开更多
This study was to develop the real-time fluorescence quantitative PCR technique for detecting the ratoon stunting disease （RSD） in virus-free seedcane seedlings. Healthy tissue culture seedlings were obtained from s...This study was to develop the real-time fluorescence quantitative PCR technique for detecting the ratoon stunting disease （RSD） in virus-free seedcane seedlings. Healthy tissue culture seedlings were obtained from six plants of sugarcane ROC22, which had been confirmed RSD-positive by detecting the sugarcane juice, by employing the sugarcane seedlings production protocol. Real-time fluorescence quantitative PCR was used to detect RSD pathogens in tissue culture sam- pies. The results showed that target fragment of RSD pathogens was not found in all 10 samples in real-time fluorescence quantitative PCR, with the Ct values of 37 - 39. The healthy tissue culture sugarcane seedlings do not carry RSD pathogens, indicating that adopting healthy seedcane seedlings production technique could thoroughly get rid of RSD pathogens.展开更多
[ Objective] This study aimed to investigate the tissue culture and rapid propagation techniques of Benihoppe strawberry. [ Method] Shoot tips of new stolons of Benihoppe strawberry were used as experimental materials...[ Objective] This study aimed to investigate the tissue culture and rapid propagation techniques of Benihoppe strawberry. [ Method] Shoot tips of new stolons of Benihoppe strawberry were used as experimental materials to analyze the effects of media type, cytokinin type and concentration, carbon source type and concentration, and light intensity on tissue culture and propagation of Benihoppe strawberry. [ Result] MS was the optimal media for plantlet propagation. In the media containing 1.2 ing/L BA （with addition of 0.1 mg/L NAA）, fresh weight, dry weight and propagation coefficient of strawberry plantlets reached the maxi- mum, which were 2.259 g, 0. 221 g and 12.4, respectively. The optimal carbon source was 30 g/L sucrose, and the optimal light intensity was 1 600 lx. [ Conclu- sion] The best media for tissue culture and rapid propagation of Benihoppe strawberry was MS ＋ BA 1.2 mg/L ＋ NAA 0. 1 mg/L ＋ sucrose 30 g/L ＋ agar 8 g/L. This study provided scientific basis for large-scale production of Benihoppe strawberry.展开更多
Virus-free sugarcane seedlings have improved biomass and sucrose content compared with ordinary seedlings, and sucrose invertases are key enzymes regulating sugarcane growth and sucrose accumulation. In this study, th...Virus-free sugarcane seedlings have improved biomass and sucrose content compared with ordinary seedlings, and sucrose invertases are key enzymes regulating sugarcane growth and sucrose accumulation. In this study, the differences in the expression levels of 3 invertase genes, CWI, SAI and NI, between virus- free and ordinary sugarcane seedlings were analyzed. Compared with ordinary sugarcane plants, the expression of CWI was mainly up-regulated in immature leaves and stems at elongation stage and leaves and immature internodes at maturation stage, and especially, greatly up-regulated in immature interuedes at maturation stage of virus-free plants. The expression of SAI and NI were mainly up-regnlated in leaves and immature internedes of virus-free plants at maturation stage, which might be beneficial to sugar accumulation and rapid utilization of monosaccharide in the stalks of virus-free plants. It is further indicated that virus-free treatment could significantly improve the expression of sucrose invertases at late growth period, and might facilitate the increase of plant biomass.展开更多
It is the simplest,fastest and effective way to improve the yield level of potato by selecting high quality virus-free seed potato for field production and maintaining the original characters of virus-free minituber. ...It is the simplest,fastest and effective way to improve the yield level of potato by selecting high quality virus-free seed potato for field production and maintaining the original characters of virus-free minituber. Microtuber is featured by small volume,no pathogen,convenient storage and transportation,which can be induced in summer with high temperature and humidity,and overcome a series of problems such as poor survival rate of transplanted test-tube plantlets,and easy pollution of cutting tips. Therefore,it can replace conventional test-tube plantlets directly for reproduction. Meantime,if minitubers are sown ahead of time using cold frame,the growth stage of potato minituber will avoid the occurrence period of aphids. The use of gauze cover for insect prevention has good effect on maintaining the excellent characters of microtuber. The yield and quality of virus-free potato are greatly improved by means of virus-free culture of shoot tip seedlings,subculture propagation of virus-free seedlings,induction of microtubers by dark culture,cultivation of breeder’s seeds in greenhouse and screenhouse to preserve the characters of potato.展开更多
At the end of potato plants vegetation virus in-fection induced both decrease in maximum amplitude of delayed fluorescence maximal amplitude and increase half time of its decrease, as well as reduction in the amount o...At the end of potato plants vegetation virus in-fection induced both decrease in maximum amplitude of delayed fluorescence maximal amplitude and increase half time of its decrease, as well as reduction in the amount of stems, plants’ height and assimilation area surface, yield, acceleration of plants development and their early die-off. The differences of DF pa-rameters and yields between strongly and weakly infected plants increase in case of a combined virus infection. In industrial test of the selection of virus-free planting potato by the use of DF parameter, a rise in the yield and de-crease degree of viral infection of crops was obtained.展开更多
THIS year＇s International AIDS Society Conference on HIV Pathogenesis, Treatment and Preven-／tion, held in Kuala Lumpur, Malaysia, made major headlines when Timothy Hendch, an American doctor, announced that two mor...THIS year＇s International AIDS Society Conference on HIV Pathogenesis, Treatment and Preven-／tion, held in Kuala Lumpur, Malaysia, made major headlines when Timothy Hendch, an American doctor, announced that two more cancer patients may have been cured of HIV after receiving bone-marrow transplants to treat lymphoma. Both patients had been taking retroviral medication, and continued to do so after the transplants as their viral levels sank until doctors were unable to find any traces of HIV in the patients＇ blood.展开更多
In order to accelerate the development of sowing mechanization of virus-free potato minituber,a conical diversion virus-free potato minituber precision seed-metering Device was designed according to the structural cha...In order to accelerate the development of sowing mechanization of virus-free potato minituber,a conical diversion virus-free potato minituber precision seed-metering Device was designed according to the structural characteristics and agronomic requirements of virus-free potato minituber.The device is mainly composed of conical turntable,transmission shaft,outer baffle of seed-metering Device,baffle,seed outlet,seed cleaning device,type hole,etc.The working principle of conical diversion precision seed-metering device for virus-free potato minituber was expounded,and the stress analysis of virus-free potato minituber in each region was carried out.By EDEM discrete element simulation software,the structure of the type hole is optimized to determine the optimal structure of the type hole and according to the physical characteristics of virus-free potato minituber,the single factor experiments of the effects of length of type hole,cone disc speed and cone disc angle on seed filling performance were completed.The orthogonal regression test was carried out with the length of type hole,cone disc speed,and cone disc angle as the test objects,and the leakage rate and qualified rate as the response indexes.The regression models of leakage rate,replay rate,and qualified rate were established,and the parameters of the regression model were optimized.The optimal parameter combination is that the length of type hole is 33.61 mm,the cone disc speed is 6.35 r/min,and the cone disc angle is 26.59°.Bench test was carried out under the optimal conditions,the leakage rate was 3.80%,the replay rate was 0.80%,and the qualified rate was 95.40%,which was basically consistent with the prediction results of the regression model,and met the requirements of precision sowing of virus-free potato minituber.展开更多
We study a proposed model describing the propagation of computer virus in the network with antidote in vulnerable system. Mathematical analysis shows that dynamics of the spread of computer viruses is determined by th...We study a proposed model describing the propagation of computer virus in the network with antidote in vulnerable system. Mathematical analysis shows that dynamics of the spread of computer viruses is determined by the threshold Ro. If Ro 〈 1, the virusfree equilibrium is globally asymptotically stable, and if R0 〉 1, the endemic equilibrium is globally asymptotically stable. Lyapunov functional method as well as geometric approach are used for proving the global stability of equilibria. A numerical investigation is carried out to confirm the analytical results. Through parameter analysis, some effective strategies for eliminating viruses are suggested.展开更多
Sweet potato virus disease is a serious biological threat to sweet potato,which seriously affects the development of sweet potato industry in China.This paper gives a brief introduction to the main defensive measures ...Sweet potato virus disease is a serious biological threat to sweet potato,which seriously affects the development of sweet potato industry in China.This paper gives a brief introduction to the main defensive measures of sweet potato virus disease,such as cutting of virus infection source,killing of viral transmission media,cultivation and application of virus-free sweet potato,use of antiviral agents,breeding of varieties with virus resistance,and mild strain cross protection,so as to provide some reference for this field.展开更多
[ Objective ] The paper was to explore effects of Tomato aspermy virus （TAV） -free on chlorophyll content and nitrogen metabolism of Chrysanthemum morifolium Ramat. ＇Huaibai＇, in order to provide a theoretical bas...[ Objective ] The paper was to explore effects of Tomato aspermy virus （TAV） -free on chlorophyll content and nitrogen metabolism of Chrysanthemum morifolium Ramat. ＇Huaibai＇, in order to provide a theoretical basis for field popularization and application of TAV-free ＇ Huai bai＇ plantlets. [ Method] With previously acquired TAV-free test-tube plantlets of ＇ Huaibai＇ as the experimental materials and its ordinary test-tube plantlets as the control （CK）, chlorophyll content and some indexes related to nitrogen metabolism in leaves were determined during subculture. [ Result] During subculture, the contents of chlorophyll a and chlorophyll b in leaves of CK and TAV-free ＇ Huaibai＇ test-tube plantlets increased with the subculture days. Both realized the largest increase at the 22＇h day of subculture, and their increase amplitudes were 5.24% and 41.69%, respectively. Compared with CK, the chlorophyll a and chlorophyll b contents of TAV-free test-tube plantlets increased at the same time point of subculture, with significant difference （P 〈0.05） or extremely significant difference （P 〈0.01 ）. Further- more, the nitrate reductase （NR） activity, free proline and soluble protein contents of TAV-free ＇ Huaibai＇ were all significantly higher than those of CK, and the highest increase amplitudes were 27.99% （ subculture for 22 d）, 28.10% （ subculture for 22 d） and 5.89% （ subculture for 38 d）, respectively. [ Conclusion] TAV-free could effectively improve chlorophyll content and nitrogen metabolism level of ＇ Huaibai＇ , and was conducive to its growth and development.展开更多
Background: Viruses can cause different diseases in plants. To prevent viral infections, plants are treated with chemical compounds and antiviral agents. Chemical antiviral agents usually have narrow specificity, whic...Background: Viruses can cause different diseases in plants. To prevent viral infections, plants are treated with chemical compounds and antiviral agents. Chemical antiviral agents usually have narrow specificity, which limits their wide application. Alternative antiviral strategy is associated with the use of microbial enzymes, which are less toxic and are readily decomposed without accumulation of harmful substances. The aim of this work is to study the effect of Bacillus pumilus ribonuclease on various phytopathogenic viruses with specific focus on the ability of enzyme to eliminate them from plant explants in vitro. Materials and methods: Extracellular ribonuclease of B. pumilus is tested as an antiviral agent. To study the antiviral effect of RNase, depending on concentration and the time of application several plant-virus model systems are used. Virus detection is conducted by serological testing and RT-PCR. Results: Bacillus pumilus ribonuclease possesses antiviral activity against plant Rna-viruses RCMV (red clover mottle virus), PVX (Potato Virus X) and AMV (Alfalfa Mosaic Virus). The maximum inhibitory effect against actively replicating viruses is observed when plants are treated with the enzyme in the concentration of 100 ug/ml prior to infection. In case of local necrosis ribonuclease in the concentration of 1 ug/ml completely inhibits the development of RCMV virus on bean plants. The enzyme is able to penetrate plants and inhibit the development of viral infection, inhibiting effect for untreated surfaces decreased on average for 20%. It is also found that B. pumilus ribonuclease protects apical explants of sprouts of potato tubers from PVM and PVS viruses. Conclusion: B. pumilus ribonuclease possesses antiviral activity against plant Rna-viruses and produces viruses-free plants in the apical meristem culture.展开更多
文摘Application of virus-free sweetpotato is a breakthrough of sweetpotato production. Several popular varieties were adopted to study their yield increase potential and their use in breeding in this research. The results showed that after virus-elimination, all varieties had a yield increase ranging from 14.95% - 91. 61% and marketable quality improvement, despite the changes in location and season. The changes of dry matter content and disease resistance were not significant. Virus-free sweetpotato performed vigorous vine growth and strong dry matter assimilation ability. Virus-free parents had a slightly high seed setting percentage, but its flowering ability and performance of off-springs were similar to that of its check plants.
基金Supported by Special Funds for Basic Scientific Research of Guangxi Sugarcane Research Institute(G2009006,G2010006,G2009015)Sci-tech Research and Development Program of Guangxi Academy of Agricultural Sciences(200805)
文摘This study was to develop the real-time fluorescence quantitative PCR technique for detecting the ratoon stunting disease （RSD） in virus-free seedcane seedlings. Healthy tissue culture seedlings were obtained from six plants of sugarcane ROC22, which had been confirmed RSD-positive by detecting the sugarcane juice, by employing the sugarcane seedlings production protocol. Real-time fluorescence quantitative PCR was used to detect RSD pathogens in tissue culture sam- pies. The results showed that target fragment of RSD pathogens was not found in all 10 samples in real-time fluorescence quantitative PCR, with the Ct values of 37 - 39. The healthy tissue culture sugarcane seedlings do not carry RSD pathogens, indicating that adopting healthy seedcane seedlings production technique could thoroughly get rid of RSD pathogens.
文摘[ Objective] This study aimed to investigate the tissue culture and rapid propagation techniques of Benihoppe strawberry. [ Method] Shoot tips of new stolons of Benihoppe strawberry were used as experimental materials to analyze the effects of media type, cytokinin type and concentration, carbon source type and concentration, and light intensity on tissue culture and propagation of Benihoppe strawberry. [ Result] MS was the optimal media for plantlet propagation. In the media containing 1.2 ing/L BA （with addition of 0.1 mg/L NAA）, fresh weight, dry weight and propagation coefficient of strawberry plantlets reached the maxi- mum, which were 2.259 g, 0. 221 g and 12.4, respectively. The optimal carbon source was 30 g/L sucrose, and the optimal light intensity was 1 600 lx. [ Conclu- sion] The best media for tissue culture and rapid propagation of Benihoppe strawberry was MS ＋ BA 1.2 mg/L ＋ NAA 0. 1 mg/L ＋ sucrose 30 g/L ＋ agar 8 g/L. This study provided scientific basis for large-scale production of Benihoppe strawberry.
基金Supported by"863"Program(2013AA102604-1)Natural Science Foundation of Hainan Province(20163124)+1 种基金Basal Research Fund for Central Public-interest Scientific Institute(ITBB140503)Earmarked Fund for China Agriculture Research System(CARS-20-2-5)
文摘Virus-free sugarcane seedlings have improved biomass and sucrose content compared with ordinary seedlings, and sucrose invertases are key enzymes regulating sugarcane growth and sucrose accumulation. In this study, the differences in the expression levels of 3 invertase genes, CWI, SAI and NI, between virus- free and ordinary sugarcane seedlings were analyzed. Compared with ordinary sugarcane plants, the expression of CWI was mainly up-regulated in immature leaves and stems at elongation stage and leaves and immature internodes at maturation stage, and especially, greatly up-regulated in immature interuedes at maturation stage of virus-free plants. The expression of SAI and NI were mainly up-regnlated in leaves and immature internedes of virus-free plants at maturation stage, which might be beneficial to sugar accumulation and rapid utilization of monosaccharide in the stalks of virus-free plants. It is further indicated that virus-free treatment could significantly improve the expression of sucrose invertases at late growth period, and might facilitate the increase of plant biomass.
基金Supported by Special Project of Potato Industry Research System in Shandong Province (SDAIT-14)。
文摘It is the simplest,fastest and effective way to improve the yield level of potato by selecting high quality virus-free seed potato for field production and maintaining the original characters of virus-free minituber. Microtuber is featured by small volume,no pathogen,convenient storage and transportation,which can be induced in summer with high temperature and humidity,and overcome a series of problems such as poor survival rate of transplanted test-tube plantlets,and easy pollution of cutting tips. Therefore,it can replace conventional test-tube plantlets directly for reproduction. Meantime,if minitubers are sown ahead of time using cold frame,the growth stage of potato minituber will avoid the occurrence period of aphids. The use of gauze cover for insect prevention has good effect on maintaining the excellent characters of microtuber. The yield and quality of virus-free potato are greatly improved by means of virus-free culture of shoot tip seedlings,subculture propagation of virus-free seedlings,induction of microtubers by dark culture,cultivation of breeder’s seeds in greenhouse and screenhouse to preserve the characters of potato.
文摘At the end of potato plants vegetation virus in-fection induced both decrease in maximum amplitude of delayed fluorescence maximal amplitude and increase half time of its decrease, as well as reduction in the amount of stems, plants’ height and assimilation area surface, yield, acceleration of plants development and their early die-off. The differences of DF pa-rameters and yields between strongly and weakly infected plants increase in case of a combined virus infection. In industrial test of the selection of virus-free planting potato by the use of DF parameter, a rise in the yield and de-crease degree of viral infection of crops was obtained.
文摘THIS year＇s International AIDS Society Conference on HIV Pathogenesis, Treatment and Preven-／tion, held in Kuala Lumpur, Malaysia, made major headlines when Timothy Hendch, an American doctor, announced that two more cancer patients may have been cured of HIV after receiving bone-marrow transplants to treat lymphoma. Both patients had been taking retroviral medication, and continued to do so after the transplants as their viral levels sank until doctors were unable to find any traces of HIV in the patients＇ blood.
基金The work was financially supported by the Major Science and Technology Special Plan of Yunnan Province Subproject(Grant No.2018ZC001-302)the National Innovation Method Work Special Project(Grant No.2018IM030106)the Talent Support Plan in Henan Province(Grant No.ZYQNBJRC2021-04).
文摘In order to accelerate the development of sowing mechanization of virus-free potato minituber,a conical diversion virus-free potato minituber precision seed-metering Device was designed according to the structural characteristics and agronomic requirements of virus-free potato minituber.The device is mainly composed of conical turntable,transmission shaft,outer baffle of seed-metering Device,baffle,seed outlet,seed cleaning device,type hole,etc.The working principle of conical diversion precision seed-metering device for virus-free potato minituber was expounded,and the stress analysis of virus-free potato minituber in each region was carried out.By EDEM discrete element simulation software,the structure of the type hole is optimized to determine the optimal structure of the type hole and according to the physical characteristics of virus-free potato minituber,the single factor experiments of the effects of length of type hole,cone disc speed and cone disc angle on seed filling performance were completed.The orthogonal regression test was carried out with the length of type hole,cone disc speed,and cone disc angle as the test objects,and the leakage rate and qualified rate as the response indexes.The regression models of leakage rate,replay rate,and qualified rate were established,and the parameters of the regression model were optimized.The optimal parameter combination is that the length of type hole is 33.61 mm,the cone disc speed is 6.35 r/min,and the cone disc angle is 26.59°.Bench test was carried out under the optimal conditions,the leakage rate was 3.80%,the replay rate was 0.80%,and the qualified rate was 95.40%,which was basically consistent with the prediction results of the regression model,and met the requirements of precision sowing of virus-free potato minituber.
文摘We study a proposed model describing the propagation of computer virus in the network with antidote in vulnerable system. Mathematical analysis shows that dynamics of the spread of computer viruses is determined by the threshold Ro. If Ro 〈 1, the virusfree equilibrium is globally asymptotically stable, and if R0 〉 1, the endemic equilibrium is globally asymptotically stable. Lyapunov functional method as well as geometric approach are used for proving the global stability of equilibria. A numerical investigation is carried out to confirm the analytical results. Through parameter analysis, some effective strategies for eliminating viruses are suggested.
基金Supported by Hunan Agricultural Science and Technology Innovation Fund(2017XC13)Changsha Sweet Potato Engineering and Technology Research Center(kq1701024)+1 种基金Hunan Sweet Potato Engineering and Technology Research Center(2018TP2032)China Agriculture Research System of Sweet Potato(CARS-11-C-16)
文摘Sweet potato virus disease is a serious biological threat to sweet potato,which seriously affects the development of sweet potato industry in China.This paper gives a brief introduction to the main defensive measures of sweet potato virus disease,such as cutting of virus infection source,killing of viral transmission media,cultivation and application of virus-free sweet potato,use of antiviral agents,breeding of varieties with virus resistance,and mild strain cross protection,so as to provide some reference for this field.
基金Supported by National Natural Science Foundation of China(31372105)Subproject of Special Research of National Traditional Chinese Medicine Industry(201407005-08)+1 种基金Support Project of Science and Technology Innovation Teams in Colleges and Universities of Henan Province(15IRTSTHN020)Project for Construction of Innovative Science and Technology Talent Team in Henan Province(C20130037)
文摘[ Objective ] The paper was to explore effects of Tomato aspermy virus （TAV） -free on chlorophyll content and nitrogen metabolism of Chrysanthemum morifolium Ramat. ＇Huaibai＇, in order to provide a theoretical basis for field popularization and application of TAV-free ＇ Huai bai＇ plantlets. [ Method] With previously acquired TAV-free test-tube plantlets of ＇ Huaibai＇ as the experimental materials and its ordinary test-tube plantlets as the control （CK）, chlorophyll content and some indexes related to nitrogen metabolism in leaves were determined during subculture. [ Result] During subculture, the contents of chlorophyll a and chlorophyll b in leaves of CK and TAV-free ＇ Huaibai＇ test-tube plantlets increased with the subculture days. Both realized the largest increase at the 22＇h day of subculture, and their increase amplitudes were 5.24% and 41.69%, respectively. Compared with CK, the chlorophyll a and chlorophyll b contents of TAV-free test-tube plantlets increased at the same time point of subculture, with significant difference （P 〈0.05） or extremely significant difference （P 〈0.01 ）. Further- more, the nitrate reductase （NR） activity, free proline and soluble protein contents of TAV-free ＇ Huaibai＇ were all significantly higher than those of CK, and the highest increase amplitudes were 27.99% （ subculture for 22 d）, 28.10% （ subculture for 22 d） and 5.89% （ subculture for 38 d）, respectively. [ Conclusion] TAV-free could effectively improve chlorophyll content and nitrogen metabolism level of ＇ Huaibai＇ , and was conducive to its growth and development.
文摘Background: Viruses can cause different diseases in plants. To prevent viral infections, plants are treated with chemical compounds and antiviral agents. Chemical antiviral agents usually have narrow specificity, which limits their wide application. Alternative antiviral strategy is associated with the use of microbial enzymes, which are less toxic and are readily decomposed without accumulation of harmful substances. The aim of this work is to study the effect of Bacillus pumilus ribonuclease on various phytopathogenic viruses with specific focus on the ability of enzyme to eliminate them from plant explants in vitro. Materials and methods: Extracellular ribonuclease of B. pumilus is tested as an antiviral agent. To study the antiviral effect of RNase, depending on concentration and the time of application several plant-virus model systems are used. Virus detection is conducted by serological testing and RT-PCR. Results: Bacillus pumilus ribonuclease possesses antiviral activity against plant Rna-viruses RCMV (red clover mottle virus), PVX (Potato Virus X) and AMV (Alfalfa Mosaic Virus). The maximum inhibitory effect against actively replicating viruses is observed when plants are treated with the enzyme in the concentration of 100 ug/ml prior to infection. In case of local necrosis ribonuclease in the concentration of 1 ug/ml completely inhibits the development of RCMV virus on bean plants. The enzyme is able to penetrate plants and inhibit the development of viral infection, inhibiting effect for untreated surfaces decreased on average for 20%. It is also found that B. pumilus ribonuclease protects apical explants of sprouts of potato tubers from PVM and PVS viruses. Conclusion: B. pumilus ribonuclease possesses antiviral activity against plant Rna-viruses and produces viruses-free plants in the apical meristem culture.
