As an important group of plant cellular organelles, the molecular mechanism of plastid division is poorly understood. Recent studies have revealed that the homologs of ftsZ gene, an essential prokaryotic cell division...As an important group of plant cellular organelles, the molecular mechanism of plastid division is poorly understood. Recent studies have revealed that the homologs of ftsZ gene, an essential prokaryotic cell division gene, are involved in plastid division process of plant cells. Antisense and sense expression constructions were employed to investigate the functions of the two ftsZ genes, NtFtsZ1 and NtFtsZ2, in transgenic Nicotiana tabacum L. plants. Although antisense expression of,NtFtsZs reduced the native protein level obviously, the size and number of chloroplasts in transgenic tobacco plants had no effect. In contrast, overexpression of NtFtsZs in transgenic plants strikingly changed the number and morphology of chloroplasts. Even only 1 - 2 huge chloroplasts could be seen in the mesophyll cells of some overexpression transgenic plants. Analyses of chloroplast ultrastructures and chlorophyll content of different transgenic plants suggested that NtFtsZs gene have no direct influence on the normal development and function of chloroplasts. ne changes in chloroplast morphology must be a compensation for the change in chloroplast number. The different phenotypes of chloroplasts in antisense and sense transgenic plants implied that different members from the same ftsZ gene family may have similar function in controlling plastid division. Meanwhile, the changes of chloroplast morphology in sense transgenic plants represented the possible plastoskeleton function of ftsZ in higher plant.展开更多
Two plastid division genes, NtFtsZ1 and NtFtsZ2 isolated from Nicotiana tabacum L. were fused with gfp and expressed in Escherichia coli . The regular localizations of full length NtFtsZs∶GFP along the fil...Two plastid division genes, NtFtsZ1 and NtFtsZ2 isolated from Nicotiana tabacum L. were fused with gfp and expressed in Escherichia coli . The regular localizations of full length NtFtsZs∶GFP along the filamentous bacteria indicated that the NtFtsZs could recognize the potential division sites in E. coli and be polymerized with heterogeneous FtsZ from bacteria. The overexpression of NtFtsZs ∶ gfp inhibited the division of host strain cells and resulted in the long filamentous bacterial morphology. These results suggested that eukaryotic ftsZs have similar function to their prokaryotic homologs. Meanwhile, the different deletions of motifs of NtFtsZs are also employed to investigate the functions of these proteins in E. coli . The results showed that the C_terminal domains of NtFtsZs were related to the correct localization of NtFtsZs in E. coli and the N_terminal domains of NtFtsZs were responsible for the polymerization of homogeneous and heterogeneous FtsZ proteins. The significance of these results in understanding the functions of NtFtsZs in plastid division were discussed.展开更多
An in vitro shoot regeneration procedure was developed in pepper （ Capsicum annuum L. ） cytoplasmic male sterility （CMS） lines 9704A and 8214A using cotyledon as explant. The callus and bud cluster derived from co...An in vitro shoot regeneration procedure was developed in pepper （ Capsicum annuum L. ） cytoplasmic male sterility （CMS） lines 9704A and 8214A using cotyledon as explant. The callus and bud cluster derived from cotyledon tissue explants were proliferated on Murashige and Skoog （MS） medium supplemented with different combinations of 6-benzladenine （6-BA）, indole-3-acetic acid （IAA）, gibberellic acid （GA3） and silver nitrate （AgNO3）. From the formula of MS appended with 5.0 mg/L 6-BA, 1.0 mg/L IAA and 5.0 mg/L AgNO3, for the explants callus and bud cluster, the maximum differentiation rates （ respectively 100.0% and 58.3% ） and average number of adventitious bud from each explant （respectively 18.8 and 13.2） were obtained. The optimum medium combination for the elongation of adventitious bud was determined to be： MS ＋ 3.0 mg/L 6-BA ＋ 1.0 mg/L IAA ＋ 5.0 mg/L AgNO3 ＋ 2.0 mg/L GA3, from which the elongation rates of buds from callus and bud cluster were both 100%, and the average number of per explant adventitious bud number reached 6.3 and 5.8, respectively. And all the elongated shoots were successfully rooted on half-strength MS medium supplemented with 0.3-0.5 mg/L IAA.展开更多
The combined lines having both phKL and Ph2-deficiency were obtained in the genetic background of common wheat (Triticum aestivum L.) landrace. These lines had normal fertility. In the wheat combined lines X Aegilops ...The combined lines having both phKL and Ph2-deficiency were obtained in the genetic background of common wheat (Triticum aestivum L.) landrace. These lines had normal fertility. In the wheat combined lines X Aegilops variabilis Eig. (or rye), a significant increase in the chiasmata of homoeologous pairing was shown by the phKL+Ph2(-) plants with respect to their phKL+Ph2 sibs, which indicates that Ph2-deficiency and phKL showed an additive effect on promoting pairing. The effects were shown in the increment of rod bivalents, ring bivalents and trivalents and reduction of univalents, of which, reduction of univalents was mainly due to the increment of rod bivalents. The combined lines are probably more desirable materials for alien gene transferring than phKL or Ph2(-) lines alone. In comparison with that of ph1b X Ae. variabilis (or rye), phKL+Ph2(-) X Ae. variabilis (or rye) show higher (or similar) numbers of rod bivalents, while the total chromosome pairing level significantly reduced that ascribed to the decrement in ring bivalents and multivalents. These results probably indicate the different genetic mechanisms for Ph1 and Ph2 or phKL on controlling homoeologous pairing.展开更多
[Objective] Pollen mother cell miosis and male gametophyte development of pumpkin were observed in this study, to provide some cytological basis for pumpkin anther or microspore culture. [Method] Ehrlich＇s hematoxyli...[Objective] Pollen mother cell miosis and male gametophyte development of pumpkin were observed in this study, to provide some cytological basis for pumpkin anther or microspore culture. [Method] Ehrlich＇s hematoxylin staining-methyl salicylate clearing technique was used for observation and research of the variation of cell structure and chromosomal behavior during pollen mother cell miosis and male gametophyte development of ‘Tianhong＇ pumpkin. [Result] The meiosis in pollen moth- er cells of pumpkin was simultaneous cytokinesis. In the process of nuclear division, nuclear membrane and nucleolus of pumpkin pollen mother cells gradually disappeared in the metaphase I and reappeared in telophase I , phragmoplast formed between the two generated crescent-shaped nuclei without cell wall, the phragmoplast gradually disappeared in the metaphase II and reappeared in telophase II. Phragmoplast spread outward from the center of spindle during the second division was connected with that formed on the central interface of two nuclei during the first division, cell wall of microspores generated from periphery to center. Most of the tetrads contained four sub-cells while a few contained extra small cells. During the period of uniuclete microspore at periphery, the single nucleolus split into 2-3 or more small nucleoli, mature pollen grain was two-celled. Mononucleate pollen cells were mostly appeared in the flower buds with length of 1.0-2.0 cm, which could be used as an important indicator to collect materials for anther or microspore culture. [Conclusion] This study laid the foundation for research of the cytogenetics of pumpkin.展开更多
The behavior of wheat-rye translocation chromosome and alien chromosome including Thinopyrum and Haynaldia chromosome at meiosis was investigated in two hybrids by fluorescence in situ hybridization (FISH). Misdivisio...The behavior of wheat-rye translocation chromosome and alien chromosome including Thinopyrum and Haynaldia chromosome at meiosis was investigated in two hybrids by fluorescence in situ hybridization (FISH). Misdivision of translocation chromosome at anaphase I and rye chromatin micronucleus at tetrad stage were observed, A plant with one normal 1BL/1RS translocation chromosome and one 1BL/1RS translocation chromosome deleted about 1/3 of rye chromosome arm in length was identified. One plant with wheat-Thinopyrum non-Robertson translocation chromosome was also detected in the F-2 population of Yi4212 x Yi4095. That could be the results of unequal misdivision of wheat-rye 1BL/1RS translocation chromosome and Thinopyrum chromosome during meiosis. No interaction between translocation chromosome and alien chromosome at meiosis was supported by the data of the distribution frequencies of translocation chromosome and Thinopyrum or Haynaldia chromosome in the progeny of two hybrids. The results may be useful to cultivate new germplasms with different length of rye 1R short arm and wheat-alien non-Robertson translocation tines under wheat background.展开更多
A nucleus-encoded MinE gene, designated PpMinE, from Physcomitrella patens was identified using RT-PCR. The presence of both N- and C-terminal extensions in PpMinE protein suggested its cyanobacterial origin. The tran...A nucleus-encoded MinE gene, designated PpMinE, from Physcomitrella patens was identified using RT-PCR. The presence of both N- and C-terminal extensions in PpMinE protein suggested its cyanobacterial origin. The transient expression of PpMinE using green fluorescent protein fusion in tobacco （Nicotiana tabacum L.） indicated that the PpMinE was a chloroplast-targeted protein. Overexpression of PpMinE in Escherichia coli caused division site misplacement and minicell formation, suggesting evolutionary functional conservation of MinE during plant phylogenesis. According to the phylogenetic tree, PpMinE protein has a close relationship with the highland plants, which suggests that the transfer events of MinE gene from plastid to nucleus might have occurred before the origin of the land plants.展开更多
文摘As an important group of plant cellular organelles, the molecular mechanism of plastid division is poorly understood. Recent studies have revealed that the homologs of ftsZ gene, an essential prokaryotic cell division gene, are involved in plastid division process of plant cells. Antisense and sense expression constructions were employed to investigate the functions of the two ftsZ genes, NtFtsZ1 and NtFtsZ2, in transgenic Nicotiana tabacum L. plants. Although antisense expression of,NtFtsZs reduced the native protein level obviously, the size and number of chloroplasts in transgenic tobacco plants had no effect. In contrast, overexpression of NtFtsZs in transgenic plants strikingly changed the number and morphology of chloroplasts. Even only 1 - 2 huge chloroplasts could be seen in the mesophyll cells of some overexpression transgenic plants. Analyses of chloroplast ultrastructures and chlorophyll content of different transgenic plants suggested that NtFtsZs gene have no direct influence on the normal development and function of chloroplasts. ne changes in chloroplast morphology must be a compensation for the change in chloroplast number. The different phenotypes of chloroplasts in antisense and sense transgenic plants implied that different members from the same ftsZ gene family may have similar function in controlling plastid division. Meanwhile, the changes of chloroplast morphology in sense transgenic plants represented the possible plastoskeleton function of ftsZ in higher plant.
文摘Two plastid division genes, NtFtsZ1 and NtFtsZ2 isolated from Nicotiana tabacum L. were fused with gfp and expressed in Escherichia coli . The regular localizations of full length NtFtsZs∶GFP along the filamentous bacteria indicated that the NtFtsZs could recognize the potential division sites in E. coli and be polymerized with heterogeneous FtsZ from bacteria. The overexpression of NtFtsZs ∶ gfp inhibited the division of host strain cells and resulted in the long filamentous bacterial morphology. These results suggested that eukaryotic ftsZs have similar function to their prokaryotic homologs. Meanwhile, the different deletions of motifs of NtFtsZs are also employed to investigate the functions of these proteins in E. coli . The results showed that the C_terminal domains of NtFtsZs were related to the correct localization of NtFtsZs in E. coli and the N_terminal domains of NtFtsZs were responsible for the polymerization of homogeneous and heterogeneous FtsZ proteins. The significance of these results in understanding the functions of NtFtsZs in plastid division were discussed.
基金Supported by "863" High Tech Project of China (2001AA241121-10) Natural Science Foundation of Yunnan Province (2005C0023Q)~~
文摘An in vitro shoot regeneration procedure was developed in pepper （ Capsicum annuum L. ） cytoplasmic male sterility （CMS） lines 9704A and 8214A using cotyledon as explant. The callus and bud cluster derived from cotyledon tissue explants were proliferated on Murashige and Skoog （MS） medium supplemented with different combinations of 6-benzladenine （6-BA）, indole-3-acetic acid （IAA）, gibberellic acid （GA3） and silver nitrate （AgNO3）. From the formula of MS appended with 5.0 mg/L 6-BA, 1.0 mg/L IAA and 5.0 mg/L AgNO3, for the explants callus and bud cluster, the maximum differentiation rates （ respectively 100.0% and 58.3% ） and average number of adventitious bud from each explant （respectively 18.8 and 13.2） were obtained. The optimum medium combination for the elongation of adventitious bud was determined to be： MS ＋ 3.0 mg/L 6-BA ＋ 1.0 mg/L IAA ＋ 5.0 mg/L AgNO3 ＋ 2.0 mg/L GA3, from which the elongation rates of buds from callus and bud cluster were both 100%, and the average number of per explant adventitious bud number reached 6.3 and 5.8, respectively. And all the elongated shoots were successfully rooted on half-strength MS medium supplemented with 0.3-0.5 mg/L IAA.
文摘The combined lines having both phKL and Ph2-deficiency were obtained in the genetic background of common wheat (Triticum aestivum L.) landrace. These lines had normal fertility. In the wheat combined lines X Aegilops variabilis Eig. (or rye), a significant increase in the chiasmata of homoeologous pairing was shown by the phKL+Ph2(-) plants with respect to their phKL+Ph2 sibs, which indicates that Ph2-deficiency and phKL showed an additive effect on promoting pairing. The effects were shown in the increment of rod bivalents, ring bivalents and trivalents and reduction of univalents, of which, reduction of univalents was mainly due to the increment of rod bivalents. The combined lines are probably more desirable materials for alien gene transferring than phKL or Ph2(-) lines alone. In comparison with that of ph1b X Ae. variabilis (or rye), phKL+Ph2(-) X Ae. variabilis (or rye) show higher (or similar) numbers of rod bivalents, while the total chromosome pairing level significantly reduced that ascribed to the decrement in ring bivalents and multivalents. These results probably indicate the different genetic mechanisms for Ph1 and Ph2 or phKL on controlling homoeologous pairing.
基金Supported by Project of Jiangsu Provincial Department of Education (JHZD06-7)Qing Lan Project of Colleges and Universities in Jiangsu Province (2008 No.30)~~
文摘[Objective] Pollen mother cell miosis and male gametophyte development of pumpkin were observed in this study, to provide some cytological basis for pumpkin anther or microspore culture. [Method] Ehrlich＇s hematoxylin staining-methyl salicylate clearing technique was used for observation and research of the variation of cell structure and chromosomal behavior during pollen mother cell miosis and male gametophyte development of ‘Tianhong＇ pumpkin. [Result] The meiosis in pollen moth- er cells of pumpkin was simultaneous cytokinesis. In the process of nuclear division, nuclear membrane and nucleolus of pumpkin pollen mother cells gradually disappeared in the metaphase I and reappeared in telophase I , phragmoplast formed between the two generated crescent-shaped nuclei without cell wall, the phragmoplast gradually disappeared in the metaphase II and reappeared in telophase II. Phragmoplast spread outward from the center of spindle during the second division was connected with that formed on the central interface of two nuclei during the first division, cell wall of microspores generated from periphery to center. Most of the tetrads contained four sub-cells while a few contained extra small cells. During the period of uniuclete microspore at periphery, the single nucleolus split into 2-3 or more small nucleoli, mature pollen grain was two-celled. Mononucleate pollen cells were mostly appeared in the flower buds with length of 1.0-2.0 cm, which could be used as an important indicator to collect materials for anther or microspore culture. [Conclusion] This study laid the foundation for research of the cytogenetics of pumpkin.
文摘The behavior of wheat-rye translocation chromosome and alien chromosome including Thinopyrum and Haynaldia chromosome at meiosis was investigated in two hybrids by fluorescence in situ hybridization (FISH). Misdivision of translocation chromosome at anaphase I and rye chromatin micronucleus at tetrad stage were observed, A plant with one normal 1BL/1RS translocation chromosome and one 1BL/1RS translocation chromosome deleted about 1/3 of rye chromosome arm in length was identified. One plant with wheat-Thinopyrum non-Robertson translocation chromosome was also detected in the F-2 population of Yi4212 x Yi4095. That could be the results of unequal misdivision of wheat-rye 1BL/1RS translocation chromosome and Thinopyrum chromosome during meiosis. No interaction between translocation chromosome and alien chromosome at meiosis was supported by the data of the distribution frequencies of translocation chromosome and Thinopyrum or Haynaldia chromosome in the progeny of two hybrids. The results may be useful to cultivate new germplasms with different length of rye 1R short arm and wheat-alien non-Robertson translocation tines under wheat background.
基金This work was supported by the National Natural Science Foundation of China (No. 30470879).
文摘A nucleus-encoded MinE gene, designated PpMinE, from Physcomitrella patens was identified using RT-PCR. The presence of both N- and C-terminal extensions in PpMinE protein suggested its cyanobacterial origin. The transient expression of PpMinE using green fluorescent protein fusion in tobacco （Nicotiana tabacum L.） indicated that the PpMinE was a chloroplast-targeted protein. Overexpression of PpMinE in Escherichia coli caused division site misplacement and minicell formation, suggesting evolutionary functional conservation of MinE during plant phylogenesis. According to the phylogenetic tree, PpMinE protein has a close relationship with the highland plants, which suggests that the transfer events of MinE gene from plastid to nucleus might have occurred before the origin of the land plants.
