Alfalfa （Medicago sativa L.） is an important forage crop in the world and it is of great signiifcance for the improvement of its salt tolerance. To improve salt tolerance in alfalfa, a rice ascorbate peroxidase gene...Alfalfa （Medicago sativa L.） is an important forage crop in the world and it is of great signiifcance for the improvement of its salt tolerance. To improve salt tolerance in alfalfa, a rice ascorbate peroxidase gene （OsAPX2） was introduced into alfalfa using Agrobacterium tumefaciens-mediated transformation with marker gene bar. The different T-DNA insertions in T1 transgenic alfalfa were identiifed by Southern hybridization. Three independent T2 transgenic lines were selected for stress analysis and the results showed that all of them were salt tolerant compared with wild-type plants. The transgenic plants had low levels of H2O2, malondialdehyde and relative electrical conductivity under salt and drought stresses. Moreover, the contents of chlorophyll and proline, and APX activity were high in transgenic plants under salt and drought stresses. Taken together, the overexpression of OsAPX2 enhances salt tolerance in alfalfa through scavenging reactive oxygen species.展开更多
Ascorbate peroxidase(APX) plays a key role in scavenging reactive oxygen species(ROS) in higher plants. However, there is very little information available on the APXs in kiwifruit(Actinidia), which is an economically...Ascorbate peroxidase(APX) plays a key role in scavenging reactive oxygen species(ROS) in higher plants. However, there is very little information available on the APXs in kiwifruit(Actinidia), which is an economically and nutritionally important horticultural crop with exceptionally high ascorbic acid(AsA) accumulation. This study aims to identify and characterize two cytosolic APX genes(AcAPX1 and AcAPX2) derived from A. chinensis ‘Hongyang’. The constitutive expression pattern was determined for both AcAPX1 and AcAPX2, and showed relatively higher expression abundances of AcAPX1 in leaf and AcAPX2 in root. Transcript levels of AcAPX1 and AcAPX2 were increased in kiwifruit roots treated with Na Cl. Subcellular localization assays using GFP-fusion proteins in Arabidopsis protoplasts showed that both AcAPX1 and AcAPX2 are targeted to the cytosol. Recombinant AcAPX1 or AcAPX2 proteins were successfully expressed in the prokaryotic expression system and their individual ascorbate peroxidase activities were determined. Finally, constitutive over-expression of AcAPX1 or AcAPX2 could dramatically increase total As A, glutathione level and salinity tolerance under Na Cl stress in Arabidopsis thaliana. Our findings revealed that cytosolic AcAPX1/2 may play an important protective role in the responses to unfavorable environmental stimuli in kiwifruit.展开更多
[Objective] The research aimed to study the correlations between catalase（CAT） and ascorbate peroxidase（ASP） and the growth and development of rice roots under cadmium stress.[Method] Taking rice variety Zhonghua ...[Objective] The research aimed to study the correlations between catalase（CAT） and ascorbate peroxidase（ASP） and the growth and development of rice roots under cadmium stress.[Method] Taking rice variety Zhonghua No.11 as materials,the changes of rice seedlings under the treatment conditions of Cd,Cd＋CAT inhibitor,Cd＋APX inhibitor were studied.[Result] Under Cd stress,inhibition of CAT activity caused the significant inhibition on the growth of aerial parts,decreased the number of adventitious roots and lateral roots,but it can significant promote the elongation growth of adventitious roots and lateral roots.Moreover,the length of the first lateral root from root tip on the primary roots and adventitious roots was also increased than control.When APX activity was inhibited,the growth changes of rice were similar with that treated by CAT inhibitor.[Conclusion] CAT and APX may play important roles in the regulation of rice root system growth in both non-stress and Cd-stressed rice展开更多
Ascorbate peroxidases （APX）, localized in the cytosol, peroxisome, mitochondria, and chloroplasts of plant cells, catalyze the reduction of H2O2 to water by using ascorbic acid as the specific electron donor. To det...Ascorbate peroxidases （APX）, localized in the cytosol, peroxisome, mitochondria, and chloroplasts of plant cells, catalyze the reduction of H2O2 to water by using ascorbic acid as the specific electron donor. To determine the role of peroxisomal type ascorbate peroxidase （pAPX）, an antioxidant enzyme, in protection against salt-induced oxidative stress, transgenic Arabidopsis thaliana plant carrying a pAPX gene （HvAPX1） from barley （Hordeum vulgate L.） was analyzed. The transgenic line pAPX3 was found to be more tolerant to salt stress than the wild type. Irrespective of salt stress, there were no significant differences in Na^＋, K^＋, Ca^2＋, and Mg^2＋ contents and the ratio of K^＋ to Na^＋ between pAPX3 and the wild type. Clearly, the salt tolerance in pAPX3 was not due to the maintenance and reestablishment of cellular ion homeostasis. However, the degree of H2O2 and lipid peroxidation （measured as the levels of malondialdehyde） accumulation under salt stress was higher in the wild type than in pAPX3. The mechanism of salt tolerance in transgenic pAPX3 can thus be explained by reduction of oxidative stress injury. Under all conditions tested, activities of superoxide, glutathione reductase, and catalase were not significantly different between pAPX3 and the wild type. In contrast, the activity of APX was significantly higher in the transgenic plant than in wild type under salt stress. These results suggested that in higher plants, HvAPX1 played an important role in salt tolerance and was a candidate gene for developing salttolerant crop plants.展开更多
Superoxide dismutase (SOD) and ascorbate peroxidase (APX) play central roles in the pathway for scavenging reactive oxygen species in plants, thereby contributing to the tolerance against abiotic stress. Here we repor...Superoxide dismutase (SOD) and ascorbate peroxidase (APX) play central roles in the pathway for scavenging reactive oxygen species in plants, thereby contributing to the tolerance against abiotic stress. Here we report the responses of cytosolic SOD (cSOD; sodCc1 and sodCc2) and cytosolic APX (cAPX; OsAPX1 and OsAPX2) genes to oxidative and abiotic stress in rice. RNA blot analyses revealed that methyl viologen treatment caused a more prominent induction of cAPXs compared with cSODs, and hydrogen peroxide treatment induced the expression of cAPXs whereas cSODs were not affected. These results suggest that cAPXs play more important roles in defense against oxidative stress compared with cSODs. It is noted that cSODs and cAPXs showed coordinate response to abscisic acid treatment which induced both sodCc1 and OsAPX2. However, cSODs and cAPXs responded differentially to drought, salt and chilling stress, which indicates that cSOD and cAPX genes are expressed differentially in response to oxidative and abiotic stress in rice.展开更多
基金supported by the National 973 Program of China (2014CB138700)
文摘Alfalfa （Medicago sativa L.） is an important forage crop in the world and it is of great signiifcance for the improvement of its salt tolerance. To improve salt tolerance in alfalfa, a rice ascorbate peroxidase gene （OsAPX2） was introduced into alfalfa using Agrobacterium tumefaciens-mediated transformation with marker gene bar. The different T-DNA insertions in T1 transgenic alfalfa were identiifed by Southern hybridization. Three independent T2 transgenic lines were selected for stress analysis and the results showed that all of them were salt tolerant compared with wild-type plants. The transgenic plants had low levels of H2O2, malondialdehyde and relative electrical conductivity under salt and drought stresses. Moreover, the contents of chlorophyll and proline, and APX activity were high in transgenic plants under salt and drought stresses. Taken together, the overexpression of OsAPX2 enhances salt tolerance in alfalfa through scavenging reactive oxygen species.
基金funded by the National Natural Science Foundation of China (31972474)the Natural Science Research Program of Universities of Anhui Province, China (K1832004)+2 种基金the Leading Talent Group Funding of Anhui Province, China (WRMR-2020-75)the Natural Science Foundation of Anhui Province, China (19232002)the Anhui Agriculture University Shennong Scholar Project, China (RC321901)。
文摘Ascorbate peroxidase(APX) plays a key role in scavenging reactive oxygen species(ROS) in higher plants. However, there is very little information available on the APXs in kiwifruit(Actinidia), which is an economically and nutritionally important horticultural crop with exceptionally high ascorbic acid(AsA) accumulation. This study aims to identify and characterize two cytosolic APX genes(AcAPX1 and AcAPX2) derived from A. chinensis ‘Hongyang’. The constitutive expression pattern was determined for both AcAPX1 and AcAPX2, and showed relatively higher expression abundances of AcAPX1 in leaf and AcAPX2 in root. Transcript levels of AcAPX1 and AcAPX2 were increased in kiwifruit roots treated with Na Cl. Subcellular localization assays using GFP-fusion proteins in Arabidopsis protoplasts showed that both AcAPX1 and AcAPX2 are targeted to the cytosol. Recombinant AcAPX1 or AcAPX2 proteins were successfully expressed in the prokaryotic expression system and their individual ascorbate peroxidase activities were determined. Finally, constitutive over-expression of AcAPX1 or AcAPX2 could dramatically increase total As A, glutathione level and salinity tolerance under Na Cl stress in Arabidopsis thaliana. Our findings revealed that cytosolic AcAPX1/2 may play an important protective role in the responses to unfavorable environmental stimuli in kiwifruit.
基金Supported by National Natural Science Foundation of China(30671126)~~
文摘[Objective] The research aimed to study the correlations between catalase（CAT） and ascorbate peroxidase（ASP） and the growth and development of rice roots under cadmium stress.[Method] Taking rice variety Zhonghua No.11 as materials,the changes of rice seedlings under the treatment conditions of Cd,Cd＋CAT inhibitor,Cd＋APX inhibitor were studied.[Result] Under Cd stress,inhibition of CAT activity caused the significant inhibition on the growth of aerial parts,decreased the number of adventitious roots and lateral roots,but it can significant promote the elongation growth of adventitious roots and lateral roots.Moreover,the length of the first lateral root from root tip on the primary roots and adventitious roots was also increased than control.When APX activity was inhibited,the growth changes of rice were similar with that treated by CAT inhibitor.[Conclusion] CAT and APX may play important roles in the regulation of rice root system growth in both non-stress and Cd-stressed rice
基金a grant of CAS (Chinese Academy of Sciences) Research Program on Soil Biosystems and Agro-Product Safety (No.CXTD-Z2005-4)the Knowledge Innovation Project of CAS (No.KZCX3-SW-439).
文摘Ascorbate peroxidases （APX）, localized in the cytosol, peroxisome, mitochondria, and chloroplasts of plant cells, catalyze the reduction of H2O2 to water by using ascorbic acid as the specific electron donor. To determine the role of peroxisomal type ascorbate peroxidase （pAPX）, an antioxidant enzyme, in protection against salt-induced oxidative stress, transgenic Arabidopsis thaliana plant carrying a pAPX gene （HvAPX1） from barley （Hordeum vulgate L.） was analyzed. The transgenic line pAPX3 was found to be more tolerant to salt stress than the wild type. Irrespective of salt stress, there were no significant differences in Na^＋, K^＋, Ca^2＋, and Mg^2＋ contents and the ratio of K^＋ to Na^＋ between pAPX3 and the wild type. Clearly, the salt tolerance in pAPX3 was not due to the maintenance and reestablishment of cellular ion homeostasis. However, the degree of H2O2 and lipid peroxidation （measured as the levels of malondialdehyde） accumulation under salt stress was higher in the wild type than in pAPX3. The mechanism of salt tolerance in transgenic pAPX3 can thus be explained by reduction of oxidative stress injury. Under all conditions tested, activities of superoxide, glutathione reductase, and catalase were not significantly different between pAPX3 and the wild type. In contrast, the activity of APX was significantly higher in the transgenic plant than in wild type under salt stress. These results suggested that in higher plants, HvAPX1 played an important role in salt tolerance and was a candidate gene for developing salttolerant crop plants.
基金supported by the Grants-in-Aid for Scientific Research (Grant No. 10460149 to K.T. and Grant No. 11740448 to S.M.) from the Ministry of Education, Culture, Sports, Science and Technology of Japana grant from the Rice Genome Research Program (Grant No. MP2106 to K.T.) from the Ministry of Agriculture, Forestry and Fisheries of Japan
文摘Superoxide dismutase (SOD) and ascorbate peroxidase (APX) play central roles in the pathway for scavenging reactive oxygen species in plants, thereby contributing to the tolerance against abiotic stress. Here we report the responses of cytosolic SOD (cSOD; sodCc1 and sodCc2) and cytosolic APX (cAPX; OsAPX1 and OsAPX2) genes to oxidative and abiotic stress in rice. RNA blot analyses revealed that methyl viologen treatment caused a more prominent induction of cAPXs compared with cSODs, and hydrogen peroxide treatment induced the expression of cAPXs whereas cSODs were not affected. These results suggest that cAPXs play more important roles in defense against oxidative stress compared with cSODs. It is noted that cSODs and cAPXs showed coordinate response to abscisic acid treatment which induced both sodCc1 and OsAPX2. However, cSODs and cAPXs responded differentially to drought, salt and chilling stress, which indicates that cSOD and cAPX genes are expressed differentially in response to oxidative and abiotic stress in rice.
