Proline is one of the most important and widespread osmolyte which functions in adaptation to adverse environmental stresses in many organisms. Also it is an important carbon and nitrogen resource in higher plants. Me...Proline is one of the most important and widespread osmolyte which functions in adaptation to adverse environmental stresses in many organisms. Also it is an important carbon and nitrogen resource in higher plants. Metabolism of proline has been elucidated in many plant species. However, transport of proline was poorly characterized although transport system plays an important role in proline distribution in different tissues. We isolated one full_length cDNA encoding proline transporter from the typical halophyte: Atriplex hortensis L. through cDNA library screening and 5′_RACE. The deduced amino acid sequence had eleven transmembrane domains, showed 60%-69% similarities to other ProTs and the gene was designated AhProT1. In the phylogenetic tree, higher plants' ProTs, e.g. AhProT1, showed more similar to ProP from microorganisms than ProT from mammalians. AhProT1 gene was transformed into Arabidopsis thaliana under 35S promoter. In MS medium containing [U_ 14 C] proline, AhProT1 + plants were able to accumulate much more radiolabeled proline in the roots than control plants. In MS medium containing different concentrations of NaCl, AhProT1 + plants could endure 200 mmol/L NaCl and keep development and biomass increase with proline supply, whereas control plants died back at 150 mmol/L NaCl.展开更多
An 888-bp ful-length ascorbate peroxidase （APX） complementary DNA （cDNA） gene was cloned from Anthurium andraeanum, and designated as AnAPX. It contains a 110-bp 5′-noncoding region, a 28-bp 3′-noncoding region,...An 888-bp ful-length ascorbate peroxidase （APX） complementary DNA （cDNA） gene was cloned from Anthurium andraeanum, and designated as AnAPX. It contains a 110-bp 5′-noncoding region, a 28-bp 3′-noncoding region, and a 750-bp open reading frame （ORF）. This protein is hydrophilic with an aliphatic index of 81.64 and its structure consisting ofα-helixes,β-turns, and random coils. The AnAPX protein showed 93%, 87%, 87%, 87%, and 86% similarities to the APX homologs from Zantedeschia aethiopica, Vitis pseudoreticulata, Gossypium hirsutum, Elaeis guineensis, and Zea mays, respectively. AnAPX gene transcript was measured non-significantly in roots, stems, leaves, spathes, and spadices by real-time polymerase chain reaction （RT-PCR） analysis. Interestingly, this gene expression was remarkably up-regulated in response to a cold stress under 6 °C, implying that AnAPX might play an important role in A. andraeanum tolerance to cold stress. To confirm this function we overexpressed AnAPX in tobacco plants by transformation with an AnAPX expression construct driven by CaMV 35S promoter. The transformed tobacco seedlings under 4 °C showed less electrolyte leakage （EL） and malondialdehyde （MDA） content than the control. The content of MDA was correlated with chilling tolerance in these transgenic plants. These results show that AnAPX can prevent the chilling challenged plant from cellmembrane damage and ultimately enhance the plant cold tolerance.展开更多
Research in the field of somatic cell nuclear transfer （SCNT） and transgenic cloning in pigs has become a global hotspot, because porcine organs probably can be the first source of donor organs for human xenotranspl...Research in the field of somatic cell nuclear transfer （SCNT） and transgenic cloning in pigs has become a global hotspot, because porcine organs probably can be the first source of donor organs for human xenotransplantation. In recent years, though great progress has been made in porcine SCNT, the efficiency of nuclear transfer remains very low （ 〈 1% ）. Thus, it is necessary to improve the procedure of nuclear transfer and to investigate some basic problems further. Recent progress and the related problems of SCNT in pigs are reviewed and analyzed so as to offer some beneficial illumination to researchers.展开更多
Connected individuals(ramets)of clonal plants are frequently fragmented due to disturbance,and such clonal fragmentation may influence their growth.However,it is unclear whether different patterns of clonal fragmentat...Connected individuals(ramets)of clonal plants are frequently fragmented due to disturbance,and such clonal fragmentation may influence their growth.However,it is unclear whether different patterns of clonal fragmentation produce differential effects on plant growth and whether such differences vary with genotypes.We collected one group of connected ramets of the stoloniferous floating invasive macrophyte Pistia stratiotes from each of six provinces(Guangdong,Guangxi,Hubei,Jiangsu,Sichuan and Yunnan Provinces)of China,and assumed that these ramets belonged to different genotypes.After several generations of vegetative propagation to remove potential parental effects,new ramets(hereafter referred to as parent ramets)from each of these assumed genotypes were subjected to four patterns of clonal fragmentation,i.e.,all offspring ramets produced during the experiment remained connected to their parent ramet(control),or the primary(1°),secondary(2°)or tertiary(3°)offspring ramets were disconnected from their parent ramet.We found significant growth differences among the assumed genotypes,confirming that the ramets sampled from these six provinces were from different genotypes.Compared with the control,disconnecting the 1°,2°or 3°ramets did not significantly affect biomass of the whole clone(i.e.,the parent ramet plus all offspring ramets)of P.stratiotes.Disconnecting the 1°ramets significantly increased biomass of the parental ramet of all six genotypes compared with the control.However,disconnecting the 2°or 3°ramets had little effect on biomass of the parent ramet for all genotypes except the Guangxi genotype,for which disconnecting the 2°ramets decreased biomass of the parent ramet.Disconnecting the 1°,2°or 3°ramets had no impact on biomass or number of the 1°or the 3°ramets for any of the genotypes.However,disconnecting the 1°ramets decreased biomass of the 2°ramets for the Guangdong and Yunnan genotypes,but had no effect for the other four genotypes.We conclude that different patterns of clonal fragmentation can have different impacts on parent and offspring ramets of P.stratiotes and such an impact may vary with genotypes.展开更多
文摘Proline is one of the most important and widespread osmolyte which functions in adaptation to adverse environmental stresses in many organisms. Also it is an important carbon and nitrogen resource in higher plants. Metabolism of proline has been elucidated in many plant species. However, transport of proline was poorly characterized although transport system plays an important role in proline distribution in different tissues. We isolated one full_length cDNA encoding proline transporter from the typical halophyte: Atriplex hortensis L. through cDNA library screening and 5′_RACE. The deduced amino acid sequence had eleven transmembrane domains, showed 60%-69% similarities to other ProTs and the gene was designated AhProT1. In the phylogenetic tree, higher plants' ProTs, e.g. AhProT1, showed more similar to ProP from microorganisms than ProT from mammalians. AhProT1 gene was transformed into Arabidopsis thaliana under 35S promoter. In MS medium containing [U_ 14 C] proline, AhProT1 + plants were able to accumulate much more radiolabeled proline in the roots than control plants. In MS medium containing different concentrations of NaCl, AhProT1 + plants could endure 200 mmol/L NaCl and keep development and biomass increase with proline supply, whereas control plants died back at 150 mmol/L NaCl.
基金supported by the Science and Technology Key Project ofZhejiang Province(No.2009C12095)the National NaturalScience Foundation of China(No.31200527)
文摘An 888-bp ful-length ascorbate peroxidase （APX） complementary DNA （cDNA） gene was cloned from Anthurium andraeanum, and designated as AnAPX. It contains a 110-bp 5′-noncoding region, a 28-bp 3′-noncoding region, and a 750-bp open reading frame （ORF）. This protein is hydrophilic with an aliphatic index of 81.64 and its structure consisting ofα-helixes,β-turns, and random coils. The AnAPX protein showed 93%, 87%, 87%, 87%, and 86% similarities to the APX homologs from Zantedeschia aethiopica, Vitis pseudoreticulata, Gossypium hirsutum, Elaeis guineensis, and Zea mays, respectively. AnAPX gene transcript was measured non-significantly in roots, stems, leaves, spathes, and spadices by real-time polymerase chain reaction （RT-PCR） analysis. Interestingly, this gene expression was remarkably up-regulated in response to a cold stress under 6 °C, implying that AnAPX might play an important role in A. andraeanum tolerance to cold stress. To confirm this function we overexpressed AnAPX in tobacco plants by transformation with an AnAPX expression construct driven by CaMV 35S promoter. The transformed tobacco seedlings under 4 °C showed less electrolyte leakage （EL） and malondialdehyde （MDA） content than the control. The content of MDA was correlated with chilling tolerance in these transgenic plants. These results show that AnAPX can prevent the chilling challenged plant from cellmembrane damage and ultimately enhance the plant cold tolerance.
文摘Research in the field of somatic cell nuclear transfer （SCNT） and transgenic cloning in pigs has become a global hotspot, because porcine organs probably can be the first source of donor organs for human xenotransplantation. In recent years, though great progress has been made in porcine SCNT, the efficiency of nuclear transfer remains very low （ 〈 1% ）. Thus, it is necessary to improve the procedure of nuclear transfer and to investigate some basic problems further. Recent progress and the related problems of SCNT in pigs are reviewed and analyzed so as to offer some beneficial illumination to researchers.
基金We thank the three anonymous reviewers for their valuable comments and the support from the National Natural Science Foundation of China(grant 31800341).
文摘Connected individuals(ramets)of clonal plants are frequently fragmented due to disturbance,and such clonal fragmentation may influence their growth.However,it is unclear whether different patterns of clonal fragmentation produce differential effects on plant growth and whether such differences vary with genotypes.We collected one group of connected ramets of the stoloniferous floating invasive macrophyte Pistia stratiotes from each of six provinces(Guangdong,Guangxi,Hubei,Jiangsu,Sichuan and Yunnan Provinces)of China,and assumed that these ramets belonged to different genotypes.After several generations of vegetative propagation to remove potential parental effects,new ramets(hereafter referred to as parent ramets)from each of these assumed genotypes were subjected to four patterns of clonal fragmentation,i.e.,all offspring ramets produced during the experiment remained connected to their parent ramet(control),or the primary(1°),secondary(2°)or tertiary(3°)offspring ramets were disconnected from their parent ramet.We found significant growth differences among the assumed genotypes,confirming that the ramets sampled from these six provinces were from different genotypes.Compared with the control,disconnecting the 1°,2°or 3°ramets did not significantly affect biomass of the whole clone(i.e.,the parent ramet plus all offspring ramets)of P.stratiotes.Disconnecting the 1°ramets significantly increased biomass of the parental ramet of all six genotypes compared with the control.However,disconnecting the 2°or 3°ramets had little effect on biomass of the parent ramet for all genotypes except the Guangxi genotype,for which disconnecting the 2°ramets decreased biomass of the parent ramet.Disconnecting the 1°,2°or 3°ramets had no impact on biomass or number of the 1°or the 3°ramets for any of the genotypes.However,disconnecting the 1°ramets decreased biomass of the 2°ramets for the Guangdong and Yunnan genotypes,but had no effect for the other four genotypes.We conclude that different patterns of clonal fragmentation can have different impacts on parent and offspring ramets of P.stratiotes and such an impact may vary with genotypes.
