Pelargonium nurseries in Europe encounter rooting problems due to the low quality of the cuttings... more Pelargonium nurseries in Europe encounter rooting problems due to the low quality of the cuttings supplied during the winter. The problem may be due to the poor quality of the stock plants from which the cuttings are harvested. The main problem that growers have is the prolonged shipping period and its effect on the viability and rootability of the cuttings once they arrive in Europe. We tested the effect of water stressing the stock plants grown grown in random block design in a commercial nursery and checked the rootability of cuttings after storage and the susceptibility of cuttings to rot. We assumed that mild water stress could harden the stock plant and thus the cuttings, and they would survive the journey better. Mild water stress improved the rooting ability of some Pelargonium varieties after days of storage compared to unstressed plants. Cuttings from water-stressed stock plants showed less decay after prolonged storage than unstressed stock plants as measured by percent r...
Flavonoids are natural pigments occurring in plants and are present in fruits, leaves, stems, roo... more Flavonoids are natural pigments occurring in plants and are present in fruits, leaves, stems, roots, and flowers. Tobacco plants transformed with an MYB regulatory gene from either Solanum chilense (Sc) or S. lycopersicum (Sl) demonstrate that ScANT1 induces a higher level of anthocyanin accumulation in comparison to SlANT1 and that this gene is sufficient to promote increased anthocyanin levels. We compared the aptitude of ScANT1 protein to induce anthocyanin accumulation to that of SlANT1 protein in tobacco plants. We also tested the effect of amino acid substitutions in ScANT1 and SlANT1. We examined these synthetic alleles' effect following the overexpression of additional anthocyanin synthesis regulators, such as the tomato bHLH (SlJAF13) protein. Our results show that the amino acid changes that differentiate ScANT1 from SlANT1 are the main contributors to the advantage that ScANT1 has over SlANT1 in anthocyanin accumulation per transcript unit. We further demonstrated that altering the amino acid composition of SlANT1 could increase anthocyanin accumulation, while reciprocally modifying ScANT1 lowers the anthocyanin level. These results confirm the increased anthocyanin level in tobacco is attributed to the amino acid differences between ScANT1 and SlANT1. We also show that the coexpression of SlJAF13 with SlANT1 in tobacco plants represses the anthocyanin production. 1 | INTRODUCTION Flavonoids are polyphenolic compounds that occur naturally in most plants and are present in fruits, leaves, stems, roots, and flowers. There are about 8000 different flavonoids that, based on their core structure, can be categorized into five major groups: chalcones, flavanones, dihydroflavonols, flavonols, and anthocyanins. Flavonoids are involved in many aspects of plant growth and survival, including pathogen resistance, recruitment of pollinators via floral pigmentation, UV light protection, pollen germination, modulation of auxin transport,
Ruscus is an evergreen shrub that offers dark-green glossy foliage used as green additions to bou... more Ruscus is an evergreen shrub that offers dark-green glossy foliage used as green additions to bouquets and flower arrangements. One of the most significant ways to obtain new varieties of crop and ornamental plants is to induce mutations by radiation. Gamma radiation is most commonly used to obtain mutants in commercial food as well as feed crops and ornamental plants. In this study, we developed tissue culture methods for Ruscus proliferation from rhizomes to obtain rhizomes clusters. These clusters were subsequently irradiated with Gamma rays to obtain unique phenotypes, such as: elongated narrow phylloclades modified stem symmetry and dwarfed growth habit. Such Ruscus types can contribute to the expansion of the floral industry.
Shoot regeneration is a key tool of modern plant biotechnology. While many researchers use this p... more Shoot regeneration is a key tool of modern plant biotechnology. While many researchers use this process empirically, very little is known about the early molecular genetic factors and signaling events that lead to shoot regeneration. Using tobacco as a model system, we found that the inductive events required for shoot regeneration occur in the first 4–5 days following incubation on regeneration medium. Leaf segments placed on regeneration medium did not produce shoots if removed from the medium before four days indicating this time frame is crucial for the induction of shoot regeneration. Leaf segments placed on regeneration medium for longer than five days maintain the capacity to produce shoots when removed from the regeneration medium. Analysis of gene expression during the early days of incubation on regeneration medium revealed many changes occurring with no single expression pattern evident among major gene families previously implicated in developmental processes. For exampl...
Plant Cell, Tissue and Organ Culture (PCTOC), 2009
A protocol for plantlet regeneration through shoot formation was developed for the neotropical sh... more A protocol for plantlet regeneration through shoot formation was developed for the neotropical shrub Brunfelsia calycina. This shrub is unique in its change in flower color from dark purple to white. Explants from young and mature leaves were incubated on MS medium (pH 5.7, 30 g/l sucrose, 7.5 g/l agar) with various combinations of Indole-3-acetic acid (IAA) and 6-Benzyladenine (BA) under a 16 h photoperiod at a constant temperature of 25°C. Shoot emergence was best at 4.44 lM BA and 2.85 lM IAA for young leaf explants, and at 8.88 lM BA, 2.85 lM IAA for mature leaf explants. When shoots were transferred to MS medium supplemented with 1.23-2.46 lM indole butrytic acid (IBA), they developed roots.
Macromolecule and cytosolic signal distribution throughout the plant employs a unique cellular an... more Macromolecule and cytosolic signal distribution throughout the plant employs a unique cellular and intracellular mechanism called plasmodesmata (PD). Plant viruses spread throughout plants via PD using their movement proteins (MPs). Viral MPs induce changes in plasmodesmata’s structure and alter their ability to move macromolecule and cytosolic signals. The developmental distribution of a family member of proteins termed plasmodesmata located proteins number 5 (PDLP5) conjugated to GFP (PDLP5-GFP) is described here. The GFP enables the visual localization of PDLP5 in the cell via confocal microscopy. We observed that PDLP5-GFP protein is present in seed protein bodies and immediately after seed imbibition in the plasma membrane. The effect of three different plant viruses, the tobacco mosaic virus (TMV), tomato brown rugose fruit virus (ToBRFV, tobamoviruses), and tomato yellow leaf curl virus (TYLCV, begomoviruses), on PDLP5-GFP accumulation at the plasmodesmata was tested. In toba...
Current Plant Science and Biotechnology in Agriculture, 1993
Cytoplasmic male sterility (CMS) is economically important and used for the production of hybrid ... more Cytoplasmic male sterility (CMS) is economically important and used for the production of hybrid seeds. The seeds will be male sterile unless the nuclear genome of the pollen parent carries nuclear male fertility restoration (MFR) alleles. A mitochondrial (mt) chimeric locus (S-Pcf) was found to be strongly associated with CMS in petunia. The S-Pcf locus contains an unidentified reading frame which is termed urf-s. The origin of this unique sequence is not known.
Echinops Asteraceae/Compositae is widespread throughout southern Europe and Asia. It is a native ... more Echinops Asteraceae/Compositae is widespread throughout southern Europe and Asia. It is a native plant in Israel and usually found as a weed in wheat fields. Due to the need of the plants for vernalization, horticultural practice is to chill the crowns for 2 month before planting to achieve early flowering. A method for the propagation of Echinops through axillary buds
... Dalia Evenor and S. Izhar Department of Plant Genetics and Breeding, Agricultural Research Or... more ... Dalia Evenor and S. Izhar Department of Plant Genetics and Breeding, Agricultural Research Organization, The Volcani Center, Bet Dagan 50250 ... Mol Gen Genet 190: 459-467 Boeshore M, Hanson MR, Lifshitz I, Izhar S Cytoplasmic male sterility-associated mitochondrial DNA ...
Light has an important role in morphogenesis of cultured plant tissue. Morphogenesis depends on b... more Light has an important role in morphogenesis of cultured plant tissue. Morphogenesis depends on both photoperiod and spectrum. Thus, the effect of light on regeneration of shoots from several petunia species leaves was studied. Sterilized leaves of petunia were placed on MS medium supplemented with 5.7 lM IAA and 2.25 lM Zeatin. Leaf tissue was exposed to varying durations of light or darkness and regeneration was recorded. Petunia hybrida cultivar R did not regenerate in darkness while P. axillaris did regenerate in darkness. P. hybrida and P. axillaris regenerated in light. P. hybrida leaves on MS regeneration medium that were exposed to light, needed a minimum of 6 days of irradiation to induced shoot regeneration. Dark-developing shoots were etiolated, which indicate that light was needed for induction of shoot morphogenesis. Crosses between P. hybrida and P. axillaris showed that there is a single dominant locus that is needed for regeneration in darkness and two loci for regeneration in light.
In the present study we examined the possibility that viruses, viroids or dsRNA are associated wi... more In the present study we examined the possibility that viruses, viroids or dsRNA are associated with cytoplasmic male sterile (cms) petunia. The assumption was made that if viruses or viroids were present, the treatments for elimination of viruses and viroids would produce "healthy" fertile plants. Male sterile plants were subjected to heat and cold treatments for 10 weeks and/ or for 5 months, after which apical meristems were isolated and cultured with the addition of antiviral factors. The mother plants, the regenerated plants and their progeny were sterile. These treatments did not affect sterility in sterile plants or the fertility of fertile plants. No dsRNA was found in cms petunia by gel electrophoresis. Thus, our data suggest that there are no viruses, viroids or dsRNA associated with eros petunia. Our data are in agreement with recent data, which suggests that the mitochondrial DNA is the site of the cytoplasmic male sterile gene in petunia.
Flower color is determined by two major factors, pigments present in the vacuole, and intra-vacuo... more Flower color is determined by two major factors, pigments present in the vacuole, and intra-vacuolar environment (vacuolar pH and metal ion content). Several reports demonstrate the importance of vacuolar pH in determining flower color, and show that increase in vacuolar pH changes the color of the petal. We study vacuolar pH in petunia flower as a model system, and the H + pumps (H + -ATPase and H + -PPase) using flower pH mutants. Two lines of petunia are being used in this study, a red line (R) with a low vacuolar pH (flower sap pH 5.6) and a purple line (P) with a high vacuolar pH (flower sap pH 6.1). ATP hydrolyzing activity of the tonoplast H + -ATPase of petals from the R line was three times higher than that from the P line. Western blot analysis showed similar amounts of the 70 kD and 58 kD subunits of vacuolar H + -ATPase in the two lines; however, subunit E amounts differed between the lines. The difference in the pH of the flower sap manifested with higher amounts of subunit E in the R line. The two lines did not differ in their organic acids synthesis. Genetic analysis of R and P lines showed that vacuolar pH is partially controlled by a single dominant gene (Ph gene).
Tomato yellow leaf curl virus (TYLCV) is a devastating disease of tomato (Solanum lycopersicum) t... more Tomato yellow leaf curl virus (TYLCV) is a devastating disease of tomato (Solanum lycopersicum) that can be effectively controlled by the deployment of resistant cultivars. The TYLCV-resistant line TY172 carries a major recessive locus for TYLCV resistance, designated ty-5, on chromosome 4. In this study, the association between 27 polymorphic DNA markers, spanning the ty-5 locus, and the resistance characteristics of individual plants inoculated with TYLCV in 51 segregating recombinant populations were analyzed. These analyses localized ty-5 into a 425 bp region containing two transversions: one in the first exon of a gene encoding the tomato homolog of the messenger RNA surveillance factor Pelota (Pelo), and a second in its proximal promoter. Analyses of susceptible and resistant lines revealed that the relative transcript level of the gene remained unchanged, regardless of whether the plants were infected with TYLCV or not. This suggests that the polymorphism discovered in the co...
Annual and perennial plants represent two different evolutionary strategies based on differential... more Annual and perennial plants represent two different evolutionary strategies based on differential synchronization of their reproductive development. The mobile signal protein FLOWERING LOCUS T (FT) plays a central role in mediating the onset of reproduction in both plant types. Two novel FT-like genes from pear (Pyrus communis)-PcFT1 and PcFT2-were isolated, and their expression profiles were determined for one annual cycle. The effects of PcFT2 on flowering were investigated in annual (tobacco) and perennial (apple) plants by means of grafting and generating transgenic plants. Long-distance graft transmission of PcFT2 in both annual and perennial plants was confirmed using a 35S::PcFT2-YFP construct. Ectopic overexpression of PcFT2 caused early flowering in tobacco but not in apple. Transgenic apples were less sensitive to short-day-induced dormancy, and this phenotype was also observed in wild-type apples grafted onto the transgenic plants. Comparison of PcFT2 protein structure to the paralogous FT proteins from apple and pear showed alterations that could influence protein structure and thus the florigen-activation complex. PcFT2 protein seems to function by promoting flowering as all other FT proteins in the annual plant tobacco while in the perennial plant apple PcFT2 does not promote flowering but delays senescence. This observation may hint to a modified function of FT2 in perennial plants.
This paper describes the relationship between the restorer gene and the gene for male sterility i... more This paper describes the relationship between the restorer gene and the gene for male sterility in the background of normal cytoplasm. We combined these two traits by crosses in one plant, thus making genetic analysis possible. Two main conclusions can be drawn: 1. The restorer gene and the gene for male sterility are located at different loci which segregate independently one from the other. 2. The Rf allele does not affect the expression of the e allele.
Pelargonium nurseries in Europe encounter rooting problems due to the low quality of the cuttings... more Pelargonium nurseries in Europe encounter rooting problems due to the low quality of the cuttings supplied during the winter. The problem may be due to the poor quality of the stock plants from which the cuttings are harvested. The main problem that growers have is the prolonged shipping period and its effect on the viability and rootability of the cuttings once they arrive in Europe. We tested the effect of water stressing the stock plants grown grown in random block design in a commercial nursery and checked the rootability of cuttings after storage and the susceptibility of cuttings to rot. We assumed that mild water stress could harden the stock plant and thus the cuttings, and they would survive the journey better. Mild water stress improved the rooting ability of some Pelargonium varieties after days of storage compared to unstressed plants. Cuttings from water-stressed stock plants showed less decay after prolonged storage than unstressed stock plants as measured by percent r...
Flavonoids are natural pigments occurring in plants and are present in fruits, leaves, stems, roo... more Flavonoids are natural pigments occurring in plants and are present in fruits, leaves, stems, roots, and flowers. Tobacco plants transformed with an MYB regulatory gene from either Solanum chilense (Sc) or S. lycopersicum (Sl) demonstrate that ScANT1 induces a higher level of anthocyanin accumulation in comparison to SlANT1 and that this gene is sufficient to promote increased anthocyanin levels. We compared the aptitude of ScANT1 protein to induce anthocyanin accumulation to that of SlANT1 protein in tobacco plants. We also tested the effect of amino acid substitutions in ScANT1 and SlANT1. We examined these synthetic alleles' effect following the overexpression of additional anthocyanin synthesis regulators, such as the tomato bHLH (SlJAF13) protein. Our results show that the amino acid changes that differentiate ScANT1 from SlANT1 are the main contributors to the advantage that ScANT1 has over SlANT1 in anthocyanin accumulation per transcript unit. We further demonstrated that altering the amino acid composition of SlANT1 could increase anthocyanin accumulation, while reciprocally modifying ScANT1 lowers the anthocyanin level. These results confirm the increased anthocyanin level in tobacco is attributed to the amino acid differences between ScANT1 and SlANT1. We also show that the coexpression of SlJAF13 with SlANT1 in tobacco plants represses the anthocyanin production. 1 | INTRODUCTION Flavonoids are polyphenolic compounds that occur naturally in most plants and are present in fruits, leaves, stems, roots, and flowers. There are about 8000 different flavonoids that, based on their core structure, can be categorized into five major groups: chalcones, flavanones, dihydroflavonols, flavonols, and anthocyanins. Flavonoids are involved in many aspects of plant growth and survival, including pathogen resistance, recruitment of pollinators via floral pigmentation, UV light protection, pollen germination, modulation of auxin transport,
Ruscus is an evergreen shrub that offers dark-green glossy foliage used as green additions to bou... more Ruscus is an evergreen shrub that offers dark-green glossy foliage used as green additions to bouquets and flower arrangements. One of the most significant ways to obtain new varieties of crop and ornamental plants is to induce mutations by radiation. Gamma radiation is most commonly used to obtain mutants in commercial food as well as feed crops and ornamental plants. In this study, we developed tissue culture methods for Ruscus proliferation from rhizomes to obtain rhizomes clusters. These clusters were subsequently irradiated with Gamma rays to obtain unique phenotypes, such as: elongated narrow phylloclades modified stem symmetry and dwarfed growth habit. Such Ruscus types can contribute to the expansion of the floral industry.
Shoot regeneration is a key tool of modern plant biotechnology. While many researchers use this p... more Shoot regeneration is a key tool of modern plant biotechnology. While many researchers use this process empirically, very little is known about the early molecular genetic factors and signaling events that lead to shoot regeneration. Using tobacco as a model system, we found that the inductive events required for shoot regeneration occur in the first 4–5 days following incubation on regeneration medium. Leaf segments placed on regeneration medium did not produce shoots if removed from the medium before four days indicating this time frame is crucial for the induction of shoot regeneration. Leaf segments placed on regeneration medium for longer than five days maintain the capacity to produce shoots when removed from the regeneration medium. Analysis of gene expression during the early days of incubation on regeneration medium revealed many changes occurring with no single expression pattern evident among major gene families previously implicated in developmental processes. For exampl...
Plant Cell, Tissue and Organ Culture (PCTOC), 2009
A protocol for plantlet regeneration through shoot formation was developed for the neotropical sh... more A protocol for plantlet regeneration through shoot formation was developed for the neotropical shrub Brunfelsia calycina. This shrub is unique in its change in flower color from dark purple to white. Explants from young and mature leaves were incubated on MS medium (pH 5.7, 30 g/l sucrose, 7.5 g/l agar) with various combinations of Indole-3-acetic acid (IAA) and 6-Benzyladenine (BA) under a 16 h photoperiod at a constant temperature of 25°C. Shoot emergence was best at 4.44 lM BA and 2.85 lM IAA for young leaf explants, and at 8.88 lM BA, 2.85 lM IAA for mature leaf explants. When shoots were transferred to MS medium supplemented with 1.23-2.46 lM indole butrytic acid (IBA), they developed roots.
Macromolecule and cytosolic signal distribution throughout the plant employs a unique cellular an... more Macromolecule and cytosolic signal distribution throughout the plant employs a unique cellular and intracellular mechanism called plasmodesmata (PD). Plant viruses spread throughout plants via PD using their movement proteins (MPs). Viral MPs induce changes in plasmodesmata’s structure and alter their ability to move macromolecule and cytosolic signals. The developmental distribution of a family member of proteins termed plasmodesmata located proteins number 5 (PDLP5) conjugated to GFP (PDLP5-GFP) is described here. The GFP enables the visual localization of PDLP5 in the cell via confocal microscopy. We observed that PDLP5-GFP protein is present in seed protein bodies and immediately after seed imbibition in the plasma membrane. The effect of three different plant viruses, the tobacco mosaic virus (TMV), tomato brown rugose fruit virus (ToBRFV, tobamoviruses), and tomato yellow leaf curl virus (TYLCV, begomoviruses), on PDLP5-GFP accumulation at the plasmodesmata was tested. In toba...
Current Plant Science and Biotechnology in Agriculture, 1993
Cytoplasmic male sterility (CMS) is economically important and used for the production of hybrid ... more Cytoplasmic male sterility (CMS) is economically important and used for the production of hybrid seeds. The seeds will be male sterile unless the nuclear genome of the pollen parent carries nuclear male fertility restoration (MFR) alleles. A mitochondrial (mt) chimeric locus (S-Pcf) was found to be strongly associated with CMS in petunia. The S-Pcf locus contains an unidentified reading frame which is termed urf-s. The origin of this unique sequence is not known.
Echinops Asteraceae/Compositae is widespread throughout southern Europe and Asia. It is a native ... more Echinops Asteraceae/Compositae is widespread throughout southern Europe and Asia. It is a native plant in Israel and usually found as a weed in wheat fields. Due to the need of the plants for vernalization, horticultural practice is to chill the crowns for 2 month before planting to achieve early flowering. A method for the propagation of Echinops through axillary buds
... Dalia Evenor and S. Izhar Department of Plant Genetics and Breeding, Agricultural Research Or... more ... Dalia Evenor and S. Izhar Department of Plant Genetics and Breeding, Agricultural Research Organization, The Volcani Center, Bet Dagan 50250 ... Mol Gen Genet 190: 459-467 Boeshore M, Hanson MR, Lifshitz I, Izhar S Cytoplasmic male sterility-associated mitochondrial DNA ...
Light has an important role in morphogenesis of cultured plant tissue. Morphogenesis depends on b... more Light has an important role in morphogenesis of cultured plant tissue. Morphogenesis depends on both photoperiod and spectrum. Thus, the effect of light on regeneration of shoots from several petunia species leaves was studied. Sterilized leaves of petunia were placed on MS medium supplemented with 5.7 lM IAA and 2.25 lM Zeatin. Leaf tissue was exposed to varying durations of light or darkness and regeneration was recorded. Petunia hybrida cultivar R did not regenerate in darkness while P. axillaris did regenerate in darkness. P. hybrida and P. axillaris regenerated in light. P. hybrida leaves on MS regeneration medium that were exposed to light, needed a minimum of 6 days of irradiation to induced shoot regeneration. Dark-developing shoots were etiolated, which indicate that light was needed for induction of shoot morphogenesis. Crosses between P. hybrida and P. axillaris showed that there is a single dominant locus that is needed for regeneration in darkness and two loci for regeneration in light.
In the present study we examined the possibility that viruses, viroids or dsRNA are associated wi... more In the present study we examined the possibility that viruses, viroids or dsRNA are associated with cytoplasmic male sterile (cms) petunia. The assumption was made that if viruses or viroids were present, the treatments for elimination of viruses and viroids would produce "healthy" fertile plants. Male sterile plants were subjected to heat and cold treatments for 10 weeks and/ or for 5 months, after which apical meristems were isolated and cultured with the addition of antiviral factors. The mother plants, the regenerated plants and their progeny were sterile. These treatments did not affect sterility in sterile plants or the fertility of fertile plants. No dsRNA was found in cms petunia by gel electrophoresis. Thus, our data suggest that there are no viruses, viroids or dsRNA associated with eros petunia. Our data are in agreement with recent data, which suggests that the mitochondrial DNA is the site of the cytoplasmic male sterile gene in petunia.
Flower color is determined by two major factors, pigments present in the vacuole, and intra-vacuo... more Flower color is determined by two major factors, pigments present in the vacuole, and intra-vacuolar environment (vacuolar pH and metal ion content). Several reports demonstrate the importance of vacuolar pH in determining flower color, and show that increase in vacuolar pH changes the color of the petal. We study vacuolar pH in petunia flower as a model system, and the H + pumps (H + -ATPase and H + -PPase) using flower pH mutants. Two lines of petunia are being used in this study, a red line (R) with a low vacuolar pH (flower sap pH 5.6) and a purple line (P) with a high vacuolar pH (flower sap pH 6.1). ATP hydrolyzing activity of the tonoplast H + -ATPase of petals from the R line was three times higher than that from the P line. Western blot analysis showed similar amounts of the 70 kD and 58 kD subunits of vacuolar H + -ATPase in the two lines; however, subunit E amounts differed between the lines. The difference in the pH of the flower sap manifested with higher amounts of subunit E in the R line. The two lines did not differ in their organic acids synthesis. Genetic analysis of R and P lines showed that vacuolar pH is partially controlled by a single dominant gene (Ph gene).
Tomato yellow leaf curl virus (TYLCV) is a devastating disease of tomato (Solanum lycopersicum) t... more Tomato yellow leaf curl virus (TYLCV) is a devastating disease of tomato (Solanum lycopersicum) that can be effectively controlled by the deployment of resistant cultivars. The TYLCV-resistant line TY172 carries a major recessive locus for TYLCV resistance, designated ty-5, on chromosome 4. In this study, the association between 27 polymorphic DNA markers, spanning the ty-5 locus, and the resistance characteristics of individual plants inoculated with TYLCV in 51 segregating recombinant populations were analyzed. These analyses localized ty-5 into a 425 bp region containing two transversions: one in the first exon of a gene encoding the tomato homolog of the messenger RNA surveillance factor Pelota (Pelo), and a second in its proximal promoter. Analyses of susceptible and resistant lines revealed that the relative transcript level of the gene remained unchanged, regardless of whether the plants were infected with TYLCV or not. This suggests that the polymorphism discovered in the co...
Annual and perennial plants represent two different evolutionary strategies based on differential... more Annual and perennial plants represent two different evolutionary strategies based on differential synchronization of their reproductive development. The mobile signal protein FLOWERING LOCUS T (FT) plays a central role in mediating the onset of reproduction in both plant types. Two novel FT-like genes from pear (Pyrus communis)-PcFT1 and PcFT2-were isolated, and their expression profiles were determined for one annual cycle. The effects of PcFT2 on flowering were investigated in annual (tobacco) and perennial (apple) plants by means of grafting and generating transgenic plants. Long-distance graft transmission of PcFT2 in both annual and perennial plants was confirmed using a 35S::PcFT2-YFP construct. Ectopic overexpression of PcFT2 caused early flowering in tobacco but not in apple. Transgenic apples were less sensitive to short-day-induced dormancy, and this phenotype was also observed in wild-type apples grafted onto the transgenic plants. Comparison of PcFT2 protein structure to the paralogous FT proteins from apple and pear showed alterations that could influence protein structure and thus the florigen-activation complex. PcFT2 protein seems to function by promoting flowering as all other FT proteins in the annual plant tobacco while in the perennial plant apple PcFT2 does not promote flowering but delays senescence. This observation may hint to a modified function of FT2 in perennial plants.
This paper describes the relationship between the restorer gene and the gene for male sterility i... more This paper describes the relationship between the restorer gene and the gene for male sterility in the background of normal cytoplasm. We combined these two traits by crosses in one plant, thus making genetic analysis possible. Two main conclusions can be drawn: 1. The restorer gene and the gene for male sterility are located at different loci which segregate independently one from the other. 2. The Rf allele does not affect the expression of the e allele.
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Papers by Dalia Evenor