![Genetic analysis of photomorphogenic mutants in tomato = [Genetische analyse van fotomorfogenese mutanten in tomaat]](/search/themes/bootstrap3/images/libros.png)
Genetic analysis of photomorphogenic mutants in tomato = [Genetische analyse van fotomorfogenese mutanten in tomaat]
To sense light quality and quantity plants possess different groups of photoreceptors. This thesis describes the isolation and characterization of several photomorphogenic mutants in the model plant tomato. The use of a genetic approach to determine the roles of the different photoreceptors, in photomorphogenesis and to study their mode of action, is one of the most promising approaches used in photomorphogenic research. M 2 populations were screened for aberrant seedling phenotypes in blue and/or red light (R). This resulted in the isolation of two allelic mutants ( fri 1 and fti 2) that resembled the phytochrome A (phyA)-deficient mutants of Arabidopsis in their far-red light (FR) insensitivity. Immunochemically detectable phyA polypeptide is absent as is the bulk of the spectrophotometrically detectable labile phytochrome pool in etiolated fri seedlings. The fri locus mapped to chromosome 10 at a position similar to that of the PhyA locus on the RFLP map. Four allelic mutants, that had longer hypocotyls under continuous R, were isolated. These mutants are only insensitive to R during the first two days upon transition from darkness to R and were designated tri 1 to tri4 (temporarily led light insensitive). Immunochemically detectable phyB1 protein is either absent, reduced or truncated. The tri mutants differ from phyB-deficient mutants found in other species in their relatively normal end-of-day FR and supplementary daytime FR responses. The tri mutant gene and the PhyB1 gene were mapped to the same position on the RFLP map of chromosome 1. The nature of the mutations in au and yg-2 was analysed by crossing both mutants with a transgenic tomato line that overexpresses oat phyA-3. Immunochemically detectable oat PHYA-3 is present in both the au,PhyA-3 and yg-2,PhyA-3 'double mutant'. However, spectrophotometrical analysis revealed that it is non active, as indicated by the long-hypocotyl phenotype of the 'double' mutants. The results were consistent with both mutants being disturbed in the phytochrome chromophore biosynthesis. The three remaining phytochrome genes (PhyB2, E and F ), for which no mutants have been found thus far, have also been mapped to the RFLP map of chromosomes 5, 2 and 7, respectively. In addition, it has been proved that there are two distinct hp loci, each with several alleles. The hp-2 gene has been located on both the genetic and molecular linkage maps of chromosome 1.
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| Format: | Doctoral thesis biblioteca |
| Language: | English |
| Published: |
Landbouwuniversiteit Wageningen
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| Subjects: | molecular genetics, moleculaire genetica, |
| Online Access: | https://research.wur.nl/en/publications/genetic-analysis-of-photomorphogenic-mutants-in-tomato-genetische |
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| Summary: | To sense light quality and quantity plants possess different groups of photoreceptors. This thesis describes the isolation and characterization of several photomorphogenic mutants in the model plant tomato. The use of a genetic approach to determine the roles of the different photoreceptors, in photomorphogenesis and to study their mode of action, is one of the most promising approaches used in photomorphogenic research. M 2 populations were screened for aberrant seedling phenotypes in blue and/or red light (R). This resulted in the isolation of two allelic mutants ( fri 1 and fti 2) that resembled the phytochrome A (phyA)-deficient mutants of Arabidopsis in their far-red light (FR) insensitivity. Immunochemically detectable phyA polypeptide is absent as is the bulk of the spectrophotometrically detectable labile phytochrome pool in etiolated fri seedlings. The fri locus mapped to chromosome 10 at a position similar to that of the PhyA locus on the RFLP map. Four allelic mutants, that had longer hypocotyls under continuous R, were isolated. These mutants are only insensitive to R during the first two days upon transition from darkness to R and were designated tri 1 to tri4 (temporarily led light insensitive). Immunochemically detectable phyB1 protein is either absent, reduced or truncated. The tri mutants differ from phyB-deficient mutants found in other species in their relatively normal end-of-day FR and supplementary daytime FR responses. The tri mutant gene and the PhyB1 gene were mapped to the same position on the RFLP map of chromosome 1. The nature of the mutations in au and yg-2 was analysed by crossing both mutants with a transgenic tomato line that overexpresses oat phyA-3. Immunochemically detectable oat PHYA-3 is present in both the au,PhyA-3 and yg-2,PhyA-3 'double mutant'. However, spectrophotometrical analysis revealed that it is non active, as indicated by the long-hypocotyl phenotype of the 'double' mutants. The results were consistent with both mutants being disturbed in the phytochrome chromophore biosynthesis. The three remaining phytochrome genes (PhyB2, E and F ), for which no mutants have been found thus far, have also been mapped to the RFLP map of chromosomes 5, 2 and 7, respectively. In addition, it has been proved that there are two distinct hp loci, each with several alleles. The hp-2 gene has been located on both the genetic and molecular linkage maps of chromosome 1. |
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