251
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Esumi T, Tao R, Yonemori K. Expression Analysis of the LFY and TFL1 Homologs in Floral Buds of Japanese Pear (Pyrus pyrifolia Nakai) and Quince (Cydonia oblonga Mill.). ACTA ACUST UNITED AC 2008. [DOI: 10.2503/jjshs1.77.128] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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252
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Sharma A, Zhang L, Niño-Liu D, Ashrafi H, Foolad MR. A Solanum lycopersicum x Solanum pimpinellifolium linkage map of tomato displaying genomic locations of R-genes, RGAs, and candidate resistance/defense-response ESTs. INTERNATIONAL JOURNAL OF PLANT GENOMICS 2008; 2008:926090. [PMID: 19223983 PMCID: PMC2639683 DOI: 10.1155/2008/926090] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2008] [Accepted: 10/20/2008] [Indexed: 05/21/2023]
Abstract
We have identified an accession (LA2093) within the tomato wild species Solanum pimpinellifolium with many desirable characteristics, including biotic and abiotic stress tolerance and good fruit quality. To utilize the full genetic potential of LA2093 in tomato breeding, we have developed a linkage map based on an F(2) population of a cross between LA2093 and a tomato breeding line, using 115 RFLP, 94 EST, and 41 RGA markers. The map spanned 1002.4 cM of the 12 tomato chromosomes with an average marker distance of 4.0 cM. The length of the map and linear order of the markers were in good agreement with the published maps of tomato. The ESTs were chosen based on their sequence similarities with known resistance or defense-response genes, signal-transduction factors, transcriptional regulators, and genes encoding pathogenesis-related proteins. Locations of several ESTs and RGAs coincided with locations of several known tomato resistance genes and quantitative resistance loci (QRLs), suggesting that candidate-gene approach may be effective in identifying and mapping new R genes. This map will be useful for marker-assisted exploitation of desirable traits in LA2093 and other S. pimpinellifolium accessions, and possibly for utilization of genetic variation within S. lycopersicum.
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Affiliation(s)
- Arun Sharma
- Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843, USA
| | - Liping Zhang
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - David Niño-Liu
- Monsanto Canada Inc., 3-75 Scurfield Boulevard Winnipeg, Manitoba, Canada R3Y 1P6
| | - Hamid Ashrafi
- Department of Plant Sciences, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Majid R. Foolad
- Department of Horticulture, The Intercollege Graduate Degree Program in Genetics, The Pennsylvania State University, University Park, PA 16802, USA
- *Majid R. Foolad:
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253
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Avila CM, Atienza SG, Moreno MT, Torres AM. Development of a new diagnostic marker for growth habit selection in faba bean (Vicia faba L.) breeding. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2007; 115:1075-82. [PMID: 17828523 DOI: 10.1007/s00122-007-0633-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Accepted: 08/10/2007] [Indexed: 05/17/2023]
Abstract
Faba bean varieties with determinacy of the apical meristem are relevant to green production. A diagnostic CAPS (cleavage amplification polymorphic sequence) marker for determinate growth habit (ti) in faba bean was previously developed by Avila et al. (Mol Breed 17:185-190, 2006) but was effective only on a limited range of cultivars or genotypes. In this study, we studied the reasons for this limited application and developed a new marker useful for most faba bean-breeding programs. By designing a new set of primers, the complete genomic Vf_TFL1 sequences from different genotypes contrasting for the character were obtained and additional base changes associated with the ti phenotype were identified. The comparison among faba bean sequences showed that the previous CAPS marker was based on a SNP (single nucleotide polymorphism) at position 469 in the intron 2-3, a silent mutation. On the contrary, a SNP at position 26 that distinguishes determinate and indeterminate growth habit genotypes lead to an amino acid change (Leu-9 to Arg) in the determinate growth habit genotypes that could account for the ti phenotype. A dCAPS marker based on this SNP that creates a TaqI site in the ti allele was developed. The marker was 100% successful in predicting ti phenotypes in a broad range of faba bean germplasm representing all major cultivars historically grown in Europe. The outcome confirms the utility of the new dCAPS in worldwide marker-assisted selection programs.
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Affiliation(s)
- C M Avila
- Departamento de Genética-ETSIAM, Universidad de Córdoba, Edificio Mendel, Campus de Rabanales, 14071 Córdoba, Spain.
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254
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Lippman ZB, Semel Y, Zamir D. An integrated view of quantitative trait variation using tomato interspecific introgression lines. Curr Opin Genet Dev 2007; 17:545-52. [PMID: 17723293 DOI: 10.1016/j.gde.2007.07.007] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Accepted: 07/17/2007] [Indexed: 02/02/2023]
Abstract
Resolving natural phenotypic variation into genetic and molecular components is a major objective in biology. Over the past decade, tomato interspecific introgression lines (ILs), each carrying a single 'exotic' chromosome segment from a wild species, have exposed thousands of quantitative trait loci (QTL) affecting plant adaptation, morphology, yield, metabolism, and gene expression. QTL for fruit size and sugar composition were isolated by map-based cloning, while others were successfully implemented in marker-assisted breeding programs. More recently, integrating the multitude of IL-QTL into a single database has unraveled some unifying principles about the architecture of complex traits in plants.
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Affiliation(s)
- Zachary B Lippman
- The Hebrew University of Jerusalem, Faculty of Agriculture, Institute of Plant Sciences, Rehovot, Israel.
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255
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Smart CD, Tanksley SD, Mayton H, Fry WE. Resistance to Phytophthora infestans in Lycopersicon pennellii. PLANT DISEASE 2007; 91:1045-1049. [PMID: 30780440 DOI: 10.1094/pdis-91-8-1045] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
To determine if the desert tomato, Lycopersicon pennellii, possesses resistance to late blight, caused by Phytophthora infestans, two plant populations were analyzed. Resistance was identified through assessments of disease progress in an F2 mapping population (L. esculentum × L. pennellii) and in a series of introgression lines (L. pennellii into L. esculentum). Levels of resistance varied widely among individuals within each population. However, the response of individuals to different strains of P. infestans was consistent. In the mapping population, a quantitative trait locus (QTL) was detected near marker T1556 on chromosome 6. This QTL accounted for 25% of the phenotypic variance in the population. The occurrence of this QTL was confirmed from analysis of the introgression lines (ILs), where IL 6-2 (containing marker T1556) was the most resistant IL in 2002 and the second most resistant IL in 2001. The identification of an additional QTL for resistance to late blight in tomato will aid in the development of durable resistance to this devastating disease.
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Affiliation(s)
| | | | - Hilary Mayton
- Department of Plant Pathology, Cornell University, Ithaca, NY 14853
| | - William E Fry
- Department of Plant Pathology, Cornell University, Ithaca, NY 14853
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256
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Welty N, Radovich C, Meulia T, van der Knaap E. Inflorescence development in two tomato species. ACTA ACUST UNITED AC 2007. [DOI: 10.1139/b06-154] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The inflorescence of tomato has been characterized as either a cyme or raceme. Cymose inflorescences are determinate, whereas racemose inflorescences are indeterminate. In this study, we addressed the discrepancy in inflorescence architecture by analyzing the morphology of a wild relative of tomato Solanum pimpinellifolium L. and four domesticated Solanum lycopersicum L. lines. Careful observation of developing inflorescences of both species showed a bifurcation of the meristem into a determinate floral and an indeterminate inflorescence meristem. Interestingly, higher fruit carpel number was associated with delayed floral development, which might give the impression of determinate growth in some of the lines. Nevertheless, our results demonstrated that tomato inflorescences are indeterminate in nature regardless of the line studied. Floral buds were formed concomitantly with the development of the inflorescence meristem and not on the flanks of the peduncle, a characteristic of racemose growth. Thus, tomato inflorescences should be classified as a cyme with the note that the inflorescence meristem does not terminate into a flower and, in fact, maintains indeterminacy. In addition, S. pimpinellifolium produced many more flowers in a highly regular manner when compared with the cultivated types. This demonstrated the usefulness of wild relatives of tomato as a tool to further understand flower and fruit development in this crop species.
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Affiliation(s)
- N. Welty
- Horticulture and Crop Sciences, The Ohio State University – Ohio Agricultural Research and Development Center (OARDC), Wooster OH 44691, USA
- Molecular and Cellular Imaging Center, The Ohio State University – Ohio Agricultural Research and Development Center (OARDC), Wooster OH 44691, USA
| | - C. Radovich
- Horticulture and Crop Sciences, The Ohio State University – Ohio Agricultural Research and Development Center (OARDC), Wooster OH 44691, USA
- Molecular and Cellular Imaging Center, The Ohio State University – Ohio Agricultural Research and Development Center (OARDC), Wooster OH 44691, USA
| | - T. Meulia
- Horticulture and Crop Sciences, The Ohio State University – Ohio Agricultural Research and Development Center (OARDC), Wooster OH 44691, USA
- Molecular and Cellular Imaging Center, The Ohio State University – Ohio Agricultural Research and Development Center (OARDC), Wooster OH 44691, USA
| | - E. van der Knaap
- Horticulture and Crop Sciences, The Ohio State University – Ohio Agricultural Research and Development Center (OARDC), Wooster OH 44691, USA
- Molecular and Cellular Imaging Center, The Ohio State University – Ohio Agricultural Research and Development Center (OARDC), Wooster OH 44691, USA
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257
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Churchman ML, Brown ML, Kato N, Kirik V, Hülskamp M, Inzé D, De Veylder L, Walker JD, Zheng Z, Oppenheimer DG, Gwin T, Churchman J, Larkin JC. SIAMESE, a plant-specific cell cycle regulator, controls endoreplication onset in Arabidopsis thaliana. THE PLANT CELL 2006; 18:3145-57. [PMID: 17098811 PMCID: PMC1693949 DOI: 10.1105/tpc.106.044834] [Citation(s) in RCA: 183] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Recessive mutations in the SIAMESE (SIM) gene of Arabidopsis thaliana result in multicellular trichomes harboring individual nuclei with a low ploidy level, a phenotype strikingly different from that of wild-type trichomes, which are single cells with a nuclear DNA content of approximately 16C to 32C. These observations suggested that SIM is required to suppress mitosis as part of the switch to endoreplication in trichomes. Here, we demonstrate that SIM encodes a nuclear-localized 14-kD protein containing a cyclin binding motif and a motif found in ICK/KRP (for Interactors of Cdc2 kinase/Kip-related protein) cell cycle inhibitor proteins. Accordingly, SIM was found to associate with D-type cyclins and CDKA;1. Homologs of SIM were detected in other dicots and in monocots but not in mammals or fungi. SIM proteins are expressed throughout the shoot apical meristem, in leaf primordia, and in the elongation zone of the root and are localized to the nucleus. Plants overexpressing SIM are slow-growing and have narrow leaves and enlarged epidermal cells with an increased DNA content resulting from additional endocycles. We hypothesize that SIM encodes a plant-specific CDK inhibitor with a key function in the mitosis-to-endoreplication transition.
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Affiliation(s)
- Michelle L Churchman
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, USA
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258
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Hsu CY, Liu Y, Luthe DS, Yuceer C. Poplar FT2 shortens the juvenile phase and promotes seasonal flowering. THE PLANT CELL 2006; 18:1846-61. [PMID: 16844908 PMCID: PMC1533980 DOI: 10.1105/tpc.106.041038] [Citation(s) in RCA: 185] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2006] [Revised: 05/10/2006] [Accepted: 06/19/2006] [Indexed: 05/10/2023]
Abstract
Many woody perennials, such as poplar (Populus deltoides), are not able to form flower buds during the first several years of their life cycle. They must undergo a transition from the juvenile phase to the reproductive phase to be competent to produce flower buds. After this transition, trees begin to form flower buds in the spring of each growing season. The genetic factors that control flower initiation, ending the juvenile phase, are unknown in poplar. The factors that regulate seasonal flower bud formation are also unknown. Here, we report that poplar FLOWERING LOCUS T2 (FT2), a relative of the Arabidopsis thaliana flowering-time gene FT, controls first-time and seasonal flowering in poplar. The FT2 transcript is rare during the juvenile phase of poplar. When juvenile poplar is transformed with FT2 and transcript levels are increased, flowering is induced within 1 year. During the transition between vegetative and reproductive growth in mature trees, FT2 transcripts are abundant during reproductive growth under long days. Subsequently, floral meristems emerge on flanks of the axillary inflorescence shoots. These findings suggest that FT2 is part of the flower initiation pathway in poplar and plays an additional role in regulating seasonal flower initiation that is integrated with the poplar perennial growth habit.
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Affiliation(s)
- Chuan-Yu Hsu
- Department of Forestry, Mississippi State University, Mississippi State, Mississippi 39762, USA
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259
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Ben-Naim O, Eshed R, Parnis A, Teper-Bamnolker P, Shalit A, Coupland G, Samach A, Lifschitz E. The CCAAT binding factor can mediate interactions between CONSTANS-like proteins and DNA. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2006; 46:462-76. [PMID: 16623906 DOI: 10.1111/j.1365-313x.2006.02706.x] [Citation(s) in RCA: 201] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
CONSTANS-Like (COL) proteins are plant-specific nuclear regulators of gene expression but do not contain a known DNA-binding motif. We tested whether a common DNA-binding protein can deliver these proteins to specific cis-acting elements. We screened for proteins that interact with two members of a subgroup of COL proteins. These COL proteins were Tomato COL1 (TCOL1), which does not seem to be involved in the control of flowering time, and the Arabidopsis thaliana CONSTANS (AtCO) protein which mediates photoperiodic induction of flowering. We show that the C-terminal plant-specific CCT (CO, CO-like, TIMING OF CAB EXPRESSION 1) domain of both proteins binds the trimeric CCAAT binding factor (CBF) via its HAP5/NF-YC component. Chromatin immunoprecipitation demonstrated that TCOL is recruited to the CCAAT motifs of the yeast CYC1 and HEM1 promoters by HAP5. In Arabidopsis, each of the three CBF components is encoded by several different genes that are highly transcribed. Under warm long days, high levels of expression of a tomato HAP5 (THAP5a) gene can reduce the flowering time of Arabidopsis. A mutation in the CCT domain of TCOL1 disrupts the interaction with THAP5 and the analogous mutation in AtCO impairs its function and delays flowering. CBFs are therefore likely to recruit COL proteins to their DNA target motifs in planta.
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Affiliation(s)
- Orna Ben-Naim
- Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
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260
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Lifschitz E, Eviatar T, Rozman A, Shalit A, Goldshmidt A, Amsellem Z, Alvarez JP, Eshed Y. The tomato FT ortholog triggers systemic signals that regulate growth and flowering and substitute for diverse environmental stimuli. Proc Natl Acad Sci U S A 2006; 103:6398-403. [PMID: 16606827 PMCID: PMC1458889 DOI: 10.1073/pnas.0601620103] [Citation(s) in RCA: 412] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The systemic model for floral induction, dubbed florigen, was conceived in photoperiod-sensitive plants but implies, in its ultimate form, a graft-transmissible signal that, although activated by different stimuli in different flowering systems, is common to all plants. We show that SFT (SINGLE-FLOWER TRUSS), the tomato ortholog of FLOWERING LOCUS T (FT), induces flowering in day-neutral tomato and tobacco plants and is encoded by SFT. sft tomato mutant plants are late-flowering, with altered architecture and flower morphology. SFT-dependent graft-transmissible signals complement all developmental defects in sft plants and substitute for long-day stimuli in Arabidopsis, short-day stimuli in Maryland Mammoth tobacco, and light-dose requirements in tomato uniflora mutant plants. The absence of donor SFT RNA from flowering receptor shoots and the localization of the protein in leaf nuclei implicate florigen-like messages in tomato as a downstream pathway triggered by cell-autonomous SFT RNA transcripts. Flowering in tomato is synonymous with termination of the shoot apical meristems, and systemic SFT messages attenuate the growth of apical meristems before and independent of floral production. Floral enhancement by systemic SFT signals is therefore one pleiotropic effect of FT orthologs.
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Affiliation(s)
- Eliezer Lifschitz
- Department of Biology, Technion Israel Institute of Technology, Haifa 32000, Israel.
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261
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Blázquez MA, Ferrándiz C, Madueño F, Parcy F. How floral meristems are built. PLANT MOLECULAR BIOLOGY 2006; 60:855-70. [PMID: 16724257 DOI: 10.1007/s11103-006-0013-z] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2005] [Accepted: 01/18/2006] [Indexed: 05/09/2023]
Abstract
The formation of flowers involves the activity of a genetic network that acts in meristems to specify floral identity. The main output of this network is the initiation of a developmental patterning program for the generation of floral organs. The first characteristic of meristem identity genes is their capacity to integrate the environmental and endogenous cues that regulate the onset of flowering. This mechanism synchronizes temporal and spatial information, ensuring that flowers arise in the correct location at the appropriate time. The second characteristic of this network is the mutual regulatory interactions established between meristem identity genes. These interactions provide flexibility and robustness against environmental noise and prevent reversion once the decision to flower has been made. Finally, the third feature is the overlap between the meristem identity and other developmental programs that operate simultaneously to regulate different aspects of the construction of flowers.
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Affiliation(s)
- Miguel A Blázquez
- Instituto de Biología Molecular y Celular de Plantas (UPV-CSIC), Universidad Politécnica de Valencia, Avda de los Naranjos s/n, Valencia, 46022, Spain.
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262
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Schauer N, Semel Y, Roessner U, Gur A, Balbo I, Carrari F, Pleban T, Perez-Melis A, Bruedigam C, Kopka J, Willmitzer L, Zamir D, Fernie AR. Comprehensive metabolic profiling and phenotyping of interspecific introgression lines for tomato improvement. Nat Biotechnol 2006; 24:447-54. [PMID: 16531992 DOI: 10.1038/nbt1192] [Citation(s) in RCA: 443] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2005] [Accepted: 01/05/2006] [Indexed: 11/08/2022]
Abstract
Tomato represents an important source of fiber and nutrients in the human diet and is a central model for the study of fruit biology. To identify components of fruit metabolic composition, here we have phenotyped tomato introgression lines (ILs) containing chromosome segments of a wild species in the genetic background of a cultivated variety. Using this high-diversity population, we identify 889 quantitative fruit metabolic loci and 326 loci that modify yield-associated traits. The mapping analysis indicates that at least 50% of the metabolic loci are associated with quantitative trait loci (QTLs) that modify whole-plant yield-associated traits. We generate a cartographic network based on correlation analysis that reveals whole-plant phenotype associated and independent metabolic associations, including links with metabolites of nutritional and organoleptic importance. The results of our genomic survey illustrate the power of genome-wide metabolic profiling and detailed morphological analysis for uncovering traits with potential for crop breeding.
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Affiliation(s)
- Nicolas Schauer
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Golm, Germany
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263
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Guo X, Zhao Z, Chen J, Hu X, Luo D. A putative CENTRORADIALIS/TERMINAL FLOWER 1-like gene, Ljcen1, plays a role in phase transition in Lotus japonicus. JOURNAL OF PLANT PHYSIOLOGY 2006; 163:436-44. [PMID: 16455357 DOI: 10.1016/j.jplph.2005.04.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2005] [Accepted: 04/27/2005] [Indexed: 05/06/2023]
Abstract
CENTRORADIALIS/TERMINAL FLOWER 1 (CEN/TFL1) genes play an important role in the phase transition of plant flowering. Here we characterized the expression pattern of a CEN/TFL1-like gene, Ljcen1, from Lotus japonicus. Sequence analysis revealed that Ljcen1 shared 67-76% identity to its homologs from a variety of plant species. Ljcen1 transcripts could be detected at the young root tip and reproductive shoot apical meristem of L. japonicus. RNA in situ hybridization analysis revealed that Ljcen1 was continuously expressed in the sub-domain of the primary inflorescence meristem and transiently expressed in the secondary inflorescence meristem. The ectopic expression of Ljcen1 in Arabidopsis driven by double CaMV 35S promoter delayed the flowering. These results suggested that Ljcen1 gene was involved in a conserved CEN/TFL1 pathway that functions in phase transition of shoot apical meristem in L. japonicus.
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Affiliation(s)
- Xizhi Guo
- National Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences.
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264
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Ahn JH, Miller D, Winter VJ, Banfield MJ, Lee JH, Yoo SY, Henz SR, Brady RL, Weigel D. A divergent external loop confers antagonistic activity on floral regulators FT and TFL1. EMBO J 2006; 25:605-14. [PMID: 16424903 PMCID: PMC1383534 DOI: 10.1038/sj.emboj.7600950] [Citation(s) in RCA: 319] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Accepted: 12/19/2005] [Indexed: 01/07/2023] Open
Abstract
The Arabidopsis genes FT and TERMINAL FLOWER1 (TFL1) encode related proteins with similarity to human Raf kinase inhibitor protein. FT, and likely also TFL1, is recruited to the promoters of floral genes through interaction with FD, a bZIP transcription factor. FT, however, induces flowering, while TFL1 represses flowering. Residues responsible for the opposite activities of FT and TFL1 were mapped by examining plants that overexpress chimeric proteins. A region important in vivo localizes to a 14-amino-acid segment that evolves very rapidly in TFL1 orthologs, but is almost invariant in FT orthologs. Crystal structures show that this segment forms an external loop of variable conformation. The only residue unambiguously distinguishing the FT and TFL1 loops makes a hydrogen bond with a residue near the entrance of a potential ligand-binding pocket in TFL1, but not in FT. This pocket is contacted by a C-terminal peptide, which also contributes to the opposite FT and TFL1 activities. In combination, these results identify a molecular surface likely to be recognized by FT- and/or TFL1-specific interactors.
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Affiliation(s)
- Ji Hoon Ahn
- Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
- College of Life Sciences and Biotechnology, Korea University, Seoul, Korea
| | - David Miller
- Department of Biochemistry, University of Bristol, Bristol, UK
| | | | - Mark J Banfield
- Department of Biochemistry, University of Bristol, Bristol, UK
| | - Jeong Hwan Lee
- College of Life Sciences and Biotechnology, Korea University, Seoul, Korea
| | - So Yeon Yoo
- College of Life Sciences and Biotechnology, Korea University, Seoul, Korea
| | - Stefan R Henz
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Robert Leo Brady
- Department of Biochemistry, University of Bristol, Bristol, UK
- Department of Biochemistry, University of Bristol, Bristol BS8 1TD, UK. Tel.: +44 117 928 7436; Fax: +44 117 928 8274; E-mail:
| | - Detlef Weigel
- Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen 72076, Germany. Tel.: +49 7071 601 1411; Fax: +49 7071 601 1412; E-mail:
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265
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Boss PK, Sreekantan L, Thomas MR. A grapevine TFL1 homologue can delay flowering and alter floral development when overexpressed in heterologous species. FUNCTIONAL PLANT BIOLOGY : FPB 2006; 33:31-41. [PMID: 32689212 DOI: 10.1071/fp05191] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2005] [Accepted: 09/14/2005] [Indexed: 06/11/2023]
Abstract
Grapevines (Vitis vinifera L.) have unusual plant architecture in that the shoot apical meristem produces both vegetative structures and primordia that are capable of forming inflorescences at regular intervals. These primordia are termed 'uncommitted' and differentiate into inflorescences or tendrils depending on the environment in which they are produced. To investigate the molecular relationship between tendrils and inflorescences and vine architecture, we cloned a TFL1 homologue from grapevine (VvTFL1). VvTFL1 is expressed in shoot apices early in latent bud development and in buds soon after bud burst. The grapevine homologue of LEAFY, VFL, is expressed at the same stages as VvTFL1 as well as in the later stages of inflorescence development. Neither VvTFL1 nor VFL were detected in tendrils. VvTFL1 was overexpressed in tobacco and Arabidopsis to confirm that it was functionally similar to TFL1 and not the close homologue FT. Flowering was delayed significantly in tobacco and Arabidopsis transformants overexpressing VvTFL1. However, an unexpected phenotype was observed in some of the transgenic Arabidopsis lines where the floral meristem became indeterminate and a new inflorescence would emerge from within the developing silique. Our findings suggest that VvTFL1 is a repressor of floral development. The nucleotide sequence reported in this paper has been submitted to GenBank under the accession number AF378127 (VvTFL1).
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Affiliation(s)
- Paul K Boss
- Cooperative Research Centre for Viticulture, CSIRO Plant Industry, Horticulture Unit, PO Box 350, Glen Osmond, SA 5064, Australia
| | - Lekha Sreekantan
- Cooperative Research Centre for Viticulture, CSIRO Plant Industry, Horticulture Unit, PO Box 350, Glen Osmond, SA 5064, Australia
| | - Mark R Thomas
- Cooperative Research Centre for Viticulture, CSIRO Plant Industry, Horticulture Unit, PO Box 350, Glen Osmond, SA 5064, Australia
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266
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Rodríguez-Falcón M, Bou J, Prat S. Seasonal control of tuberization in potato: conserved elements with the flowering response. ANNUAL REVIEW OF PLANT BIOLOGY 2006; 57:151-80. [PMID: 16669759 DOI: 10.1146/annurev.arplant.57.032905.105224] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Fluctuations in day length determine the time to flower in many plants and in potato are critical to promote differentiation of tubers. Day length is perceived in the leaves and under inductive conditions these synthesize a systemic signal that is transported to the underground stolons to induce tuber development. Flowering tobacco shoots grafted into potato stocks promote tuberization in the stocks, indicating that the floral and tuber-inducing signals might be similar. We describe recent progress in the identification of the molecular mechanisms underlying day-length recognition in potato. Evidence has been obtained for a conserved function of the potato orthologs of the CONSTANS (CO) and FLOWERING LOCUS T (FT) proteins in tuberization control under short days (SDs). These observations indicate that common regulatory pathways are involved in both flowering and tuberization photoperiodic responses in plants.
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Affiliation(s)
- Mariana Rodríguez-Falcón
- Departamento Genética Molecular de Plantas, Centro Nacional de Biotecnología-CSIC, Campus Universidad Autónoma de Madrid, 28049 Madrid, Spain
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267
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Quinet M, Dielen V, Batoko H, Boutry M, Havelange A, Kinet JM. Genetic interactions in the control of flowering time and reproductive structure development in tomato (Solanum lycopersicum). THE NEW PHYTOLOGIST 2006; 170:701-10. [PMID: 16684232 DOI: 10.1111/j.1469-8137.2006.01717.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Different tomato (Solanum lycopersicum) mutants, affected in flowering time, reproductive structure or plant architecture, were crossed to produce double mutants in order to investigate gene interactions in flowering regulation in this autonomous species with a sympodial growth habit. The compound inflorescence: uniflora, uniflora: self pruning, uniflora: blind, and jointless: uniflora double mutants all produced solitary flowers like their uniflora parent, instead of inflorescences. All double mutants were late flowering. uniflora: blind and uniflora: self pruning had flowering times intermediate between those of their two parents. jointless: uniflora and compound inflorescence: uniflora flowered later than uniflora, the mutant with the most delayed flowering. All double mutants developed strong lateral shoots at node levels approximately corresponding to the level at which their parent cultivars initiated their first reproductive structure, which is a typical trait of uniflora. These results suggest that the UNIFLORA gene acts upstream of the other investigated genes in controlling flowering in tomato, and that floral transition of the primary shoot and floral transition of sympodial segments are regulated differently.
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Affiliation(s)
- Muriel Quinet
- Unité de Biologie Végétale, Département de Biologie et Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 5, boîte 13, B-1348 Louvain-la-Neuve, Belgium
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268
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Chardon F, Damerval C. Phylogenomic analysis of the PEBP gene family in cereals. J Mol Evol 2005; 61:579-90. [PMID: 16170456 DOI: 10.1007/s00239-004-0179-4] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2004] [Accepted: 05/24/2005] [Indexed: 10/25/2022]
Abstract
The TFL1 and FT genes, which are key genes in the control of flowering time in Arabidopsis thaliana, belong to a small multigene family characterized by a specific phosphatidylethanolamine-binding protein domain, termed the PEBP gene family. Several PEBP genes are found in dicots and monocots, and act on the control of flowering time. We investigated the evolution of the PEBP gene family in cereals. First, taking advantage of the complete rice genome sequence and EST databases, we found 19 PEBP genes in this species, 6 of which were not previously described. Ten genes correspond to five pairs of paralogs mapped on known duplicated regions of the rice genome. Phylogenetic analysis of Arabidopsis and rice genes indicates that the PEBP gene family consists of three main homology classes (the so-called TFL1-LIKE, MFT-LIKE, and FT-LIKE subfamilies), in which gene duplication and/or loss occurred independently in Arabidopsis and rice. Second, phylogenetic analyses of genomic and EST sequences from five cereal species indicate that the three subfamilies of PEBP genes have been conserved in cereals. The tree structure suggests that the ancestral grass genome had at least two MFT-like genes, two TFL1-like genes, and eight FT-like genes. A phylogenomic approach leads to some hypotheses about conservation of gene function within the subfamilies.
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Affiliation(s)
- Fabien Chardon
- Station de génétique végétale, UMR de Génétique Végétale, INRA/UPS/CNRS/INAPG, Ferme du Moulon, 91190 Gif-sur-Yvette, France
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269
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High-resolution fine mapping and fluorescence in situ hybridization analysis of sun, a locus controlling tomato fruit shape, reveals a region of the tomato genome prone to DNA rearrangements. Genetics 2005; 168:2127-40. [PMID: 15611181 DOI: 10.1534/genetics.104.031013] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The locus sun on the short arm of tomato chromosome 7 controls morphology of the fruit. Alleles from wild relatives impart a round shape, while alleles from certain cultivated varieties impart an oval shape typical of roma-type tomatoes. We fine mapped the locus in two populations and investigated the genome organization of the region spanning and flanking sun. The first high-resolution genetic map of the sun locus was constructed using a nearly isogenic F(2) population derived from a cross between Lycopersicon pennellii introgression line IL7-4 and L. esculentum cv Sun1642. The mapping combined with results from pachytene FISH experiments demonstrated that the top of chromosome 7 is inverted in L. pennellii accession LA716. sun was located close to the chromosomal breakpoint and within the inversion, thereby precluding map-based cloning of the gene using this population. The fruit-shape locus was subsequently fine mapped in a population derived from a cross between L. esculentum Sun1642 and L. pimpinellifolium LA1589. Chromosome walking using clones identified from several large genomic insert libraries resulted in two noncontiguous contigs flanking sun. Fiber-FISH analysis showed that distance between the two contigs measured 68 kb in L. esculentum Sun1642 and 38 kb in L. pimpinellifolium LA1589, respectively. The sun locus mapped between the two contigs, suggesting that allelic variation at this locus may be due to an insertion/deletion event. The results demonstrate that sun is located in a highly dynamic region of the tomato genome.
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270
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Angenent GC, Stuurman J, Snowden KC, Koes R. Use of Petunia to unravel plant meristem functioning. TRENDS IN PLANT SCIENCE 2005; 10:243-50. [PMID: 15882657 DOI: 10.1016/j.tplants.2005.03.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
In the past decade, enormous progress has been made in our understanding of the molecular and genetic control of meristem growth, maintenance and differentiation into plant organs. Several model plants have contributed to our current knowledge of meristem function. Research using Petunia has had a substantial share in this progress. Integration of information obtained from this species gives clues about the common and diverged pathways underlying the formation and functioning of plant meristems.
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Affiliation(s)
- Gerco C Angenent
- Business Unit Bioscience, Plant Research International, PO Box 16, 6700 AA Wageningen, The Netherlands.
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271
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Esumi T, Tao R, Yonemori K. Isolation of LEAFY and TERMINAL FLOWER 1 homologues from six fruit tree species in the subfamily Maloideae of the Rosaceae. ACTA ACUST UNITED AC 2005. [DOI: 10.1007/s00497-004-0239-3] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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272
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Chautard H, Jacquet M, Schoentgen F, Bureaud N, Bénédetti H. Tfs1p, a member of the PEBP family, inhibits the Ira2p but not the Ira1p Ras GTPase-activating protein in Saccharomyces cerevisiae. EUKARYOTIC CELL 2004; 3:459-70. [PMID: 15075275 PMCID: PMC387632 DOI: 10.1128/ec.3.2.459-470.2004] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Ras proteins are guanine nucleotide-binding proteins that are highly conserved among eukaryotes. They are involved in signal transduction pathways and are tightly regulated by two sets of antagonistic proteins: GTPase-activating proteins (GAPs) inhibit Ras proteins, whereas guanine exchange factors activate them. In this work, we describe Tfs1p, the first physiological inhibitor of a Ras GAP, Ira2p, in Saccharomyces cerevisiae. TFS1 is a multicopy suppressor of the cdc25-1 mutation in yeast and corresponds to the so-called Ic CPY cytoplasmic inhibitor. Moreover, Tfs1p belongs to the phosphatidylethanolamine-binding protein (PEBP) family, one member of which is RKIP, a kinase and serine protease inhibitor and a metastasis inhibitor in prostate cancer. In this work, the results of (i) a two-hybrid screen of a yeast genomic library, (ii) glutathione S-transferase pulldown experiments, (iii) multicopy suppressor tests of cdc25-1 mutants, and (iv) stress resistance tests to evaluate the activation level of Ras demonstrate that Tfs1p interacts with and inhibits Ira2p. We further show that the conserved ligand-binding pocket of Tfs1-the hallmark of the PEBP family-is important for its inhibitory activity.
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Affiliation(s)
- Hélène Chautard
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique, UPR 4301, University of Orléans and INSERM, 45071 Orléans Cedex 2, France
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273
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Mizrachy L, Dabush D, Levy Y, Aloni R, Altman A, Gafni Y. Cloning and characterization of the tomato karyopherin alpha1 gene promoter. Dev Growth Differ 2004; 46:515-22. [PMID: 15610141 DOI: 10.1111/j.1440-169x.2004.00766.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The karyopherin alpha1 (LeKAPalpha 1) gene of tomato (Lycopersicon esculentum) encodes a receptor involved in nuclear import. To analyze the expression pattern of this gene, a genomic clone containing its upstream region was isolated and sequenced. To study the promoter functionality, a 2170 bp fragment (LM1), was fused to glucuronidase (GUS) and introduced into petunia cells by particle bombardment. For further characterization of the promoter, one inverse and three deletion constructs were studied in cell suspension. To follow its expression in tobacco leaves, transgenic plants expressing GUS under the control of the LM1 promoter were made. Expression of LM1-GUS was largely restricted to actively growing leaf regions, suggesting possible involvement of active cell division and plant growth regulators in LeKAPalpha 1 expression.
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Affiliation(s)
- Liat Mizrachy
- Department of Genetics, Agricultural Research Organization, The Volcani Center, PO Box 6, Bet Dagan 50250, Israel
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274
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Pillitteri LJ, Lovatt CJ, Walling LL. Isolation and characterization of a TERMINAL FLOWER homolog and its correlation with juvenility in citrus. PLANT PHYSIOLOGY 2004; 135:1540-51. [PMID: 15235113 PMCID: PMC519069 DOI: 10.1104/pp.103.036178] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2003] [Revised: 02/27/2004] [Accepted: 02/28/2004] [Indexed: 05/19/2023]
Abstract
TERMINAL FLOWER is a key regulator of floral timing in Arabidopsis and other herbaceous species. A homolog of this gene, CsTFL, was isolated from the hybrid perennial tree crop Washington navel orange (Citrus sinensis L. Osbeck). The deduced amino acid sequence of CsTFL was 65% identical to the Arabidopsis TFL1 protein. Wild-type Arabidopsis plants ectopically expressing CsTFL showed late-flowering phenotypes similar to those described for overexpression of Arabidopsis TFL1. In addition, the 35S:CsTFL transgene complemented the tfl1-2 mutant. The severity of the overexpression phenotypes correlated with the amount of CsTFL transcript that accumulated. Unlike many model systems that have been studied, C. sinensis maintains two distinguishable CsTFL alleles. CsTFL transcripts from either allele were not detected in adult vegetative tissues using reverse transcription-PCR, but CsTFL RNAs were detected in all floral organs. In addition, real-time PCR determined that juvenility in citrus was positively correlated with CsTFL transcript accumulation and negatively correlated with the floral-regulatory genes, LEAFY and APETALA1, RNA levels.
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Affiliation(s)
- Lynn Jo Pillitteri
- Department of Botany and Plant Sciences, Center for Plant Cell Biology, University of California, Riverside, California 92521-0124, USA
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275
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Menda N, Semel Y, Peled D, Eshed Y, Zamir D. In silico screening of a saturated mutation library of tomato. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2004; 38:861-72. [PMID: 15144386 DOI: 10.1111/j.1365-313x.2004.02088.x] [Citation(s) in RCA: 154] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
A comprehensive mutant population is a basic resource for exploring gene function. We developed an isogenic tomato 'mutation library' in the genetic background of the inbred variety M82. A total of 13 000 M(2) families, derived from EMS (ethyl methane sulfonate) and fast-neutron mutagenesis, were visually phenotyped in the field and categorized into a morphological catalog that includes 15 primary and 48 secondary categories. Currently, 3417 mutations have been cataloged; among them are most of the previously described phenotypes from the monogenic mutant collection of The Tomato Genetics Resource Center, and over a thousand new mutants, with multiple alleles per locus. The phenotypic database indicates that most mutations fall into more than a single category (pleiotropic), with some organs such as leaves more prone to alterations than others. All data and images can be searched and accessed in the Solanaceae Genome Network (SGN) on a site called 'The Genes That Make Tomatoes' (http://zamir.sgn.cornell.edu/mutants/).
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Affiliation(s)
- Naama Menda
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, and the Otto Warburg Center for Agricultural Biotechnology, Faculty of Agriculture, The Hebrew University of Jerusalem, PO Box 12, Rehovot 76100, Israel
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276
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Brouwer DJ, Jones ES, St Clair DA. QTL analysis of quantitative resistance toPhytophthora infestans(late blight) in tomato and comparisons with potato. Genome 2004; 47:475-92. [PMID: 15190365 DOI: 10.1139/g04-001] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Quantitative trait loci (QTLs) for resistance to Phytophthora infestans (late blight) were mapped in tomato. Reciprocal backcross populations derived from cultivated Lycopersicon esculentum × wild Lycopersicon hirsutum (BC-E, backcross to L. esculentum; BC-H, backcross to L. hirsutum) were phenotyped in three types of replicated disease assays (detached-leaflet, whole-plant, and field). Linkage maps were constructed for each BC population with RFLPs. Resistance QTLs were identified on all 12 tomato chromosomes using composite interval mapping. Six QTLs in BC-E (lb1a, lb2a, lb3, lb4, lb5b, and lb11b) and two QTLs in BC-H (lb5ab and lb6ab) were most consistently detected in replicated experiments or across assay methods. Lycopersicon hirsutum alleles conferred resistance at all QTLs except lb2a. Resistance QTLs coincided with QTLs for inoculum droplet dispersal on leaves, a trait in L. hirsutum that may contribute to resistance, and dispersal was mainly associated with leaf resistance. Some P. infestans resistance QTLs detected in tomato coincided with chromosomal locations of previously mapped R genes and QTLs for resistance to P. infestans in potato, suggesting functional conservation of resistance within the Solanaceae.Key words: late blight, tomato, Lycopersicon hirsutum, QTL mapping, disease resistance, potato.
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Affiliation(s)
- Douglas J Brouwer
- Department of Vegetable Crops, University of California, Davis 95616, USA
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277
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Sagi M, Davydov O, Orazova S, Yesbergenova Z, Ophir R, Stratmann JW, Fluhr R. Plant respiratory burst oxidase homologs impinge on wound responsiveness and development in Lycopersicon esculentum. THE PLANT CELL 2004; 16:616-28. [PMID: 14973161 PMCID: PMC385276 DOI: 10.1105/tpc.019398] [Citation(s) in RCA: 184] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2003] [Accepted: 12/19/2003] [Indexed: 05/18/2023]
Abstract
Plant respiratory burst oxidase homologs (Rboh) are homologs of the human neutrophil pathogen-related gp91(phox). Antisense technology was employed to ascertain the biological function of Lycopersicon esculentum (tomato) Rboh. Lines with diminished Rboh activity showed a reduced level of reactive oxygen species (ROS) in the leaf, implying a role for Rboh in establishing the cellular redox milieu. Surprisingly, the antisense plants acquired a highly branched phenotype, switched from indeterminate to determinate growth habit, and had fasciated reproductive organs. Wound-induced systemic expression of proteinase inhibitor II was compromised in the antisense lines, indicating that ROS intermediates supplied by Rboh are required for this wound response. Extending these observations by transcriptome analysis revealed ectopic leaf expression of homeotic MADS box genes that are normally expressed only in reproductive organs. In addition, both Rboh-dependent and -independent wound-induced gene induction was detected as well as transcript changes related to redox maintenance. The results provide novel insights into how the steady state cellular level of ROS is controlled and portrays the role of Rboh as a signal transducer of stress and developmental responses.
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Affiliation(s)
- Moshe Sagi
- Institute for Applied Research, Ben-Gurion University, Beer Sheva 84105, Israel.
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278
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Dielen V, Quinet M, Chao J, Batoko H, Havelange A, Kinet JM. UNIFLORA, a pivotal gene that regulates floral transition and meristem identity in tomato (Lycopersicon esculentum). THE NEW PHYTOLOGIST 2004; 161:393-400. [PMID: 33873503 DOI: 10.1046/j.1469-8137.2003.00937.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
• Flowering of uniflora (uf), a tomato (Lycopersicon esculentum) mutant which consistently produces solitary flowers instead of inflorescences, is late and highly asynchronous in winter. This puzzling behaviour prompted us to further investigate flowering regulation in this mutant to improve our understanding of UNIFLORA gene function. • Growing plants under different daylengths and light intensities revealed that flowering time in uf is dependent on daily light energy integral. Transferring plants from low to high light energy integrals at different times after sowing showed that the light-conditions effect was stage dependent, suggesting that interactions between light energy integrals and endogenous regulatory pathways affect meristem sensitivity to flowering signals. • Carbohydrate analyses suggested that one of these signals could be sucrose, but other interacting factors are probably generated by the root system, as indicated by grafting experiments. • The UNIFLORA gene thus appears to have a dual role in tomato: floral transition regulation and the maintenance of inflorescence meristem identity.
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Affiliation(s)
- Vincent Dielen
- Unité de Biologie végétale, Département de Biologie et Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 5, boîte 13, B-1348 Louvain-la-Neuve, Belgium
| | - Muriel Quinet
- Unité de Biologie végétale, Département de Biologie et Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 5, boîte 13, B-1348 Louvain-la-Neuve, Belgium
| | - Jaime Chao
- Unité de Biologie végétale, Département de Biologie et Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 5, boîte 13, B-1348 Louvain-la-Neuve, Belgium
| | - Henri Batoko
- Unité de Biologie végétale, Département de Biologie et Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 5, boîte 13, B-1348 Louvain-la-Neuve, Belgium
| | - Andrée Havelange
- Laboratoire de Physiologie végétale, Département des Sciences de la Vie, Université de Liège, Bât. B 22 - Botanique, Sart Tilman, B-4000 Liège, Belgium
| | - Jean-Marie Kinet
- Unité de Biologie végétale, Département de Biologie et Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 5, boîte 13, B-1348 Louvain-la-Neuve, Belgium
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279
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Abstract
Plant architecture is species specific, indicating that it is under strict genetic control. Although it is also influenced by environmental conditions such as light, temperature, humidity and nutrient status, here we wish to focus only on the endogenous regulatory principles that control plant architecture. We summarise recent progress in the understanding of the basic patterning mechanisms involved in the regulation of leaf arrangement, the genetic regulation of meristem determinacy, i.e. the decision to stop or continue growth, and the control of branching during vegetative and generative development. Finally, we discuss the basis of leaf architecture and the role of cell division and cell growth in morphogenesis.
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280
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Goff SA, Ricke D, Lan TH, Presting G, Wang R, Dunn M, Glazebrook J, Sessions A, Oeller P, Varma H, Hadley D, Hutchison D, Martin C, Katagiri F, Lange BM, Moughamer T, Xia Y, Budworth P, Zhong J, Miguel T, Paszkowski U, Zhang S, Colbert M, Sun WL, Chen L, Cooper B, Park S, Wood TC, Mao L, Quail P, Wing R, Dean R, Yu Y, Zharkikh A, Shen R, Sahasrabudhe S, Thomas A, Cannings R, Gutin A, Pruss D, Reid J, Tavtigian S, Mitchell J, Eldredge G, Scholl T, Miller RM, Bhatnagar S, Adey N, Rubano T, Tusneem N, Robinson R, Feldhaus J, Macalma T, Oliphant A, Briggs S. A draft sequence of the rice genome (Oryza sativa L. ssp. japonica). Science 2002; 296:92-100. [PMID: 11935018 DOI: 10.1126/science.1068275] [Citation(s) in RCA: 1840] [Impact Index Per Article: 83.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The genome of the japonica subspecies of rice, an important cereal and model monocot, was sequenced and assembled by whole-genome shotgun sequencing. The assembled sequence covers 93% of the 420-megabase genome. Gene predictions on the assembled sequence suggest that the genome contains 32,000 to 50,000 genes. Homologs of 98% of the known maize, wheat, and barley proteins are found in rice. Synteny and gene homology between rice and the other cereal genomes are extensive, whereas synteny with Arabidopsis is limited. Assignment of candidate rice orthologs to Arabidopsis genes is possible in many cases. The rice genome sequence provides a foundation for the improvement of cereals, our most important crops.
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Affiliation(s)
- Stephen A Goff
- Torrey Mesa Research Institute, Syngenta, 3115 Merryfield Row, San Diego, CA 92121, USA.
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281
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Zhang LP, Khan A, Niño-Liu D, Foolad MR. A molecular linkage map of tomato displaying chromosomal locations of resistance gene analogs based on a Lycopersicon esculentum x Lycopersicon hirsutum cross. Genome 2002; 45:133-46. [PMID: 11908656 DOI: 10.1139/g01-124] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A molecular linkage map of tomato was constructed based on a BC1 population (N = 145) of a cross between Lycopersicon esculentum Mill. line NC84173 (maternal and recurrent parent) and Lycopersicon hirsutum Humb. and Bonpl. accession PI126445. NC84173 is an advanced breeding line that is resistant to several tomato diseases, not including early blight (EB) and late blight (LB). PI126445 is a self-incompatible accession that is resistant to many tomato diseases, including EB and LB. The map included 142 restriction fragment length polymorphism (RFLP) markers and 29 resistance gene analogs (RGAs). RGA loci were identified by PCR amplification of genomic DNA from the BC1 population, using ten pairs of degenerate oligonucleotide primers designed based on conserved leucine-rich repeat (LRR), nucleotide binding site (NBS), and serine (threonine) protein kinase (PtoKin) domains of known resistance genes (R genes). The PCR-amplified DNAs were separated by denaturing polyacrylamide gel electrophoresis (PAGE), which allowed separation of heterogeneous products and identification and mapping of individual RGA loci. The map spanned 1469 cM of the 12 tomato chromosomes with an average marker distance of 8.6 cM. The RGA loci were mapped to 9 of the 12 tomato chromosomes. Locations of some RGAs coincided with locations of several known tomato R genes or quantitative resistance loci (QRLs), including Cf-1, Cf-4, Cf-9, Cf-ECP2, rx-1, and Cm1.1 (chromosome 1); Tm-1 (chromosome 2); Asc (chrromosme 3); Pto, Fen, and Prf (chromosome 5); 01-1, Mi, Ty-1, Cm6.1, Cf-2, CF-5, Bw-5, and Bw-1 (chromosome 6); I-1, 1-3, and Ph-1 (chromosome 7); Tm-2a and Fr1 (chromosome 9); and Lv (chromosome 12). These co-localizations indicate that the RGA loci were either linked to or part of the known R genes. Furthermore, similar to that for many R gene families, several RGA loci were found in clusters, suggesting their potential evolutionary relationship with R genes. Comparisons of the present map with other molecular linkage maps of tomato, including the high density L. esculentum x Lycopersicon pennellii map, indicated that the lengths of the maps and linear order of RFLP markers were in good agreement, though certain chromosomal regions were less consistent than others in terms of the frequency of recombination. The present map provides a basis for identification and mapping of genes and QTLs for disease resistance and other desirable traits in PI126445 and other L. hirsutum accessions, and will be useful for marker-assisted selection and map-based gene cloning in tomato.
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Affiliation(s)
- L P Zhang
- Department of Horticulture, The Pennsylvania State University, University Park 16802, USA
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282
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Shepard KA, Purugganan MD. The genetics of plant morphological evolution. CURRENT OPINION IN PLANT BIOLOGY 2002; 5:49-55. [PMID: 11788308 DOI: 10.1016/s1369-5266(01)00227-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Considerable progress has been made in identifying genes that are involved in the evolution of plant morphologies. Elements of the ABC model of flower development are conserved throughout angiosperms, and homologous MADS-box genes function in gymnosperm reproduction. Candidate gene and mapping analyses of floral symmetry, sex determination, inflorescence architecture, and compound leaves provide intriguing glimpses into the evolution of morphological adaptations.
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Affiliation(s)
- Kristen A Shepard
- Department of Genetics, Box 7614, 3513 Gardner Hall, North Carolina State University, Raleigh, North Carolina 27695, USA.
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283
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Schmitz G, Tillmann E, Carriero F, Fiore C, Cellini F, Theres K. The tomato Blind gene encodes a MYB transcription factor that controls the formation of lateral meristems. Proc Natl Acad Sci U S A 2002; 99:1064-9. [PMID: 11805344 PMCID: PMC117430 DOI: 10.1073/pnas.022516199] [Citation(s) in RCA: 204] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The multitude of forms observed in flowering plants is largely because of their ability to establish new axes of growth during postembryonic development. This process is initiated by the formation of secondary meristems that develop into vegetative or reproductive branches. In the blind and torosa mutants of tomato, initiation of lateral meristems is blocked during shoot and inflorescence development, leading to a strong reduction in the number of lateral axes. In this study, it is shown that blind and torosa are allelic. The Blind gene has been isolated by positional cloning, and it was found that the mutant phenotype is caused by a loss of function of an R2R3 class Myb gene. RNA interference-induced blind phenocopies confirmed the identity of the isolated gene. Double mutant analysis shows that Blind acts in a novel pathway different from the one to which the previously identified Lateral suppressor gene belongs. The findings reported add a new class of transcription factors to the group of genes controlling lateral meristem initiation and reveal a previously uncharacterized function of R2R3 Myb genes.
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Affiliation(s)
- Gregor Schmitz
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829 Cologne, Germany
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284
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Kroslak T, Koch T, Kahl E, Höllt V. Human phosphatidylethanolamine-binding protein facilitates heterotrimeric G protein-dependent signaling. J Biol Chem 2001; 276:39772-8. [PMID: 11514577 DOI: 10.1074/jbc.m106991200] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In this study we report that human phosphatidylethanolamine-binding protein (hPBP) facilitates heterotrimeric G protein-coupled signaling. In Xenopus laevis oocytes, coexpression of hPBP with human mu opioid receptor, human delta opioid receptor, or human somatostatin receptor 2 evoked an agonist-induced increase in potassium conductance of G protein-activated inwardly rectifying potassium channels. This activation of heterotrimeric G protein signaling in oocytes could also be elicited by injection of bacterially overexpressed and purified hPBP. Stimulatory effect was pertussis toxin-sensitive and present even in the absence of coexpressed receptors. Additionally, an increase in G protein-mediated inhibition of adenylate cyclase activity, measured by the inhibition of forskolin-mediated cAMP accumulation, could be detected in HEK293 and NIH3T3 cells after expression of hPBP and in Xenopus oocytes after injection of hPBP. As [(35)S]guanosine 5'-3-O-(thio)triphosphate (GTPgammaS) binding to membranes prepared from hPBP-expressing cells was significantly elevated and recombinant hPBP dose-dependently stimulated [(35)S]GTPgammaS binding to native membranes, the results presented provide strong evidence that hPBP-induced effects are G protein-dependent. These data suggest a novel function of hPBP in regulating G protein and G protein-coupled receptor signaling in vivo.
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Affiliation(s)
- T Kroslak
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University of Magdeburg, Leipzigerstrasse 44, D-39120 Magdeburg, Germany
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285
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Serre L, Pereira de Jesus K, Zelwer C, Bureaud N, Schoentgen F, Bénédetti H. Crystal structures of YBHB and YBCL from Escherichia coli, two bacterial homologues to a Raf kinase inhibitor protein. J Mol Biol 2001; 310:617-34. [PMID: 11439028 DOI: 10.1006/jmbi.2001.4784] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In rat and human cells, RKIP (previously known as PEBP) was characterized as an inhibitor of the MEK phosphorylation by Raf-1. In Escherichia coli, the genes ybhb and ybcl possibly encode two RKIP homologues while in the genomes of other bacteria and archaebacteria other homologous genes of RKIP have been found. The parallel between the cellular signaling mechanisms in eukaryotes and prokaryotes suggests that these bacterial proteins could be involved in the regulation of protein phosphorylation by kinases as well. We first showed that the proteins YBHB and YBCL were present in the cytoplasm and periplasm of E. coli, respectively, after which we determined their crystallographic structures. These structures verify that YBHB and YBCL belong to the same structural family as mammalian RKIP/PEBP proteins. The general fold and the anion binding site of these proteins are extremely well conserved between mammals and bacteria and suggest functional similarities. However, the bacterial proteins also exhibit some specific structural features, like a substrate binding pocket formed by the dimerization interface and the absence of cis peptide bonds. This structural variety should correspond to the recognition of multiple cellular partners.
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Affiliation(s)
- L Serre
- Centre de Biophysique Moléculaire, C.N.R.S., U.P.R. 4301, rue Charles Sadron 45071, Orléans, Cedex 2, France.
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286
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Haag ES, True JR. Perspective: From mutants to mechanisms? Assessing the candidate gene paradigm in evolutionary biology. Evolution 2001; 55:1077-84. [PMID: 11475043 DOI: 10.1111/j.0014-3820.2001.tb00627.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The generation of mutants in model organisms by geneticists and developmental biologists over the last century has occasionally produced phenotypes that are startlingly reminiscent of those seen in other species. Such extreme mutations have generally been dismissed by evolutionary geneticists since the "modern synthesis" as irrelevant to adaptation and speciation. But only in recent years has information on the molecular bases of mutant phenotypes become widely available, and thus work on testing the relevance of such extreme mutations to the generation of phylogenetic diversity has just begun. Here we evaluate whether evolutionary mimics are, in fact, useful for pinpointing the genetic differences that distinguish morphological variants generated during evolution. Examples come from both plants and animals, and range from intraspecific to interordinal taxonomic ranges. The use of mutationally defined candidate genes to predict evolutionary mechanisms has so far been most fruitful in explaining intraspecific variants, where it has been effective in both plants and animals. In several cases these efforts were facilitated or supported by parallel results from quantitative trait loci studies, in which natural alleles controlling continuous variation in developmental model organisms were mapped to mutationally defined genes. However, despite these successes the approach's utility seems to rapidly decay as a function of phylogenetic distance. This suggests that the divergence of developmental genetic systems is great even in closely related organisms and may become intractable at larger distances. We discuss this result in the context of what it teaches us about development, the future prospects of the candidate gene approach, and the historical debate over process in micro- and macroevolution.
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Affiliation(s)
- E S Haag
- Department of Biochemistry, University of Wisconsin, Madison 53706, USA.
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287
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Mimida N, Goto K, Kobayashi Y, Araki T, Ahn JH, Weigel D, Murata M, Motoyoshi F, Sakamoto W. Functional divergence of the TFL1-like gene family in Arabidopsis revealed by characterization of a novel homologue. Genes Cells 2001; 6:327-36. [PMID: 11318875 DOI: 10.1046/j.1365-2443.2001.00425.x] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The TERMINAL FLOWER 1 (TFL1) gene of Arabidopsis plays an important role in regulating flowering time and in maintaining the fate of inflorescence meristem (IM). TFL1 is a homologue of CENTRORADIALIS (CEN) from Antirrhinum, which is only involved in IM maintenance. Recent mutational studies and the genome project revealed that TFL1 belongs to a small gene family in Arabidopsis, in which functional divergence may have occurred among the members. RESULTS We found a new member of the TFL1 gene family, which is mapped on chromosome 2 of Arabidopsis. The predicted protein sequence encoded by this gene is more closely related to that of CEN than other Arabidopsis TFL1 homologues (and therefore named ATC for Arabidopsis thaliana CENTRORADIALIS homologue). Transgenic plants constitutively expressing the ATC gene (35S:ATC), in either wild-type or tfl1 mutant backgrounds, showed a phenotype similar to that observed in transgenic plants constitutively expressing the TFL1 gene. However, in contrast to TFL1, the expression of ATC was only detected in the hypocotyl of young plants, and not in the IM. In addition, an atc loss-of-function mutant, isolated by screening a T-DNA library, showed no phenotypes that were similar to those of tfl1 mutants. CONCLUSION The phenotypes of transgenic plants over-expressing ATC suggest that the ATC protein can functionally substitute for TFL1. However, the pattern and level of expression and the loss-of-function phenotype indicate that ATC does not participate in the regulation of IM identity, but rather has a role that is different from that of TFL1.
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Affiliation(s)
- N Mimida
- Research Institute for Bioresources, Okayama University, Kurashiki, Okayama 710-0046, Japan
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288
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Dielen V, Lecouvet V, Dupont S, Kinet JM. In vitro control of floral transition in tomato (Lycopersicon esculentum Mill.), the model for autonomously flowering plants, using the late flowering uniflora mutant. JOURNAL OF EXPERIMENTAL BOTANY 2001; 52:715-723. [PMID: 11413208 DOI: 10.1093/jexbot/52.357.715] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In vitro control of floral transition in tomato (Lycopersicon esculentum Mill.), the model plant for autonomously flowering species has been investigated using the late flowering mutant uniflora (uf). Apices collected from truly vegetative plants were cultivated on solid media supplemented with different combinations of growth regulators and chemicals. Several chemical factors implicated in the promotion of floral transition of the uf mutant have been identified: sucrose, cytokinins and nitrogenous nutrients have all to be supplied at optimal concentrations. In contrast, gibberellic acid was found to be inhibitory. These results are discussed in relation to knowledge accumulated on the nature of the flowering signals circulating, at floral transition, in other plants, especially in photoperiodic species. This study suggests that tomato could constitute an adequate model to investigate the genetic and physiological control of floral transition and contribute in unravelling pathways which are constitutively regulating this important step of plant life cycle.
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Affiliation(s)
- V Dielen
- Laboratoire de Cytogénétique, Département de Biologie, Université catholique de Louvain, Croix du Sud, 13-5, B-1348, Louvain-la-Neuve, Belgium.
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289
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Gocal GF, King RW, Blundell CA, Schwartz OM, Andersen CH, Weigel D. Evolution of floral meristem identity genes. Analysis of Lolium temulentum genes related to APETALA1 and LEAFY of Arabidopsis. PLANT PHYSIOLOGY 2001; 125:1788-801. [PMID: 11299359 PMCID: PMC88835 DOI: 10.1104/pp.125.4.1788] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2000] [Revised: 12/18/2000] [Accepted: 01/10/2001] [Indexed: 05/17/2023]
Abstract
Flowering (inflorescence formation) of the grass Lolium temulentum is strictly regulated, occurring rapidly on exposure to a single long day (LD). During floral induction, L. temulentum differs significantly from dicot species such as Arabidopsis in the expression, at the shoot apex, of two APETALA1 (AP1)-like genes, LtMADS1 and LtMADS2, and of L. temulentum LEAFY (LtLFY). As shown by in situ hybridization, LtMADS1 and LtMADS2 are expressed in the vegetative shoot apical meristem, but expression increases strongly within 30 h of LD floral induction. Later in floral development, LtMADS1 and LtMADS2 are expressed within spikelet and floret meristems and in the glume and lemma primordia. It is interesting that LtLFY is detected quite late (about 12 d after LD induction) within the spikelet meristems, glumes, and lemma primordia. These patterns contrast with Arabidopsis, where LFY and AP1 are consecutively activated early during flower formation. LtMADS2, when expressed in transgenic Arabidopsis plants under the control of the AP1 promoter, could partially complement the organ number defect of the severe ap1-15 mutant allele, confirming a close relationship between LtMADS2 and AP1.
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Affiliation(s)
- G F Gocal
- Commonwealth Scientific and Industrial Research Organization, Division of Plant Industry, G.P.O. Box 1600, Canberra, ACT 2601, Australia
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290
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Jensen CS, Salchert K, Nielsen KK. A TERMINAL FLOWER1-like gene from perennial ryegrass involved in floral transition and axillary meristem identity. PLANT PHYSIOLOGY 2001; 125:1517-28. [PMID: 11244130 PMCID: PMC65629 DOI: 10.1104/pp.125.3.1517] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2000] [Revised: 12/18/2000] [Accepted: 12/22/2000] [Indexed: 05/17/2023]
Abstract
Control of flowering and the regulation of plant architecture have been thoroughly investigated in a number of well-studied dicot plants such as Arabidopsis, Antirrhinum, and tobacco. However, in many important monocot seed crops, molecular information on plant reproduction is still limited. To investigate the regulation of meristem identity and the control of floral transition in perennial ryegrass (Lolium perenne) we isolated a ryegrass TERMINAL FLOWER1-like gene, LpTFL1, and characterized it for its function in ryegrass flower development. Perennial ryegrass requires a cold treatment of at least 12 weeks to induce flowering. During this period a decrease in LpTFL1 message was detected in the ryegrass apex. However, upon subsequent induction with elevated temperatures and long-day photoperiods, LpTFL1 message levels increased and reached a maximum when the ryegrass apex has formed visible spikelets. Arabidopsis plants overexpressing LpTFL1 were significantly delayed in flowering and exhibited dramatic changes in architecture such as extensive lateral branching, increased growth of all vegetative organs, and a highly increased trichome production. Furthermore, overexpression of LpTFL1 was able to complement the phenotype of the severe tfl1-14 mutant of Arabidopsis. Analysis of the LpTFL1 promoter fused to the UidA gene in Arabidopsis revealed that the promoter is active in axillary meristems, but not the apical meristem. Therefore, we suggest that LpTFL1 is a repressor of flowering and a controller of axillary meristem identity in ryegrass.
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Affiliation(s)
- C S Jensen
- Department of Plant Biology and Biogeochemistry, RISOE National Laboratory, P.O. Box 49, DK-4000 Roskilde, Denmark
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291
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292
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Haag ES, True JR. PERSPECTIVE:FROM MUTANTS TO MECHANISMS? ASSESSING THE CANDIDATE GENE PARADIGM IN EVOLUTIONARY BIOLOGY. Evolution 2001. [DOI: 10.1554/0014-3820(2001)055[1077:pfmtma]2.0.co;2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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293
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Ronen G, Carmel-Goren L, Zamir D, Hirschberg J. An alternative pathway to beta -carotene formation in plant chromoplasts discovered by map-based cloning of beta and old-gold color mutations in tomato. Proc Natl Acad Sci U S A 2000; 97:11102-7. [PMID: 10995464 PMCID: PMC27155 DOI: 10.1073/pnas.190177497] [Citation(s) in RCA: 343] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Carotenoid pigments in plants fulfill indispensable functions in photosynthesis. Carotenoids that accumulate as secondary metabolites in chromoplasts provide distinct coloration to flowers and fruits. In this work we investigated the genetic mechanisms that regulate accumulation of carotenoids as secondary metabolites during ripening of tomato fruits. We analyzed two mutations that affect fruit pigmentation in tomato (Lycopersicon esculentum): Beta (B), a single dominant gene that increases beta-carotene in the fruit, and old-gold (og), a recessive mutation that abolishes beta-carotene and increases lycopene. Using a map-based cloning approach we cloned the genes B and og. Molecular analysis revealed that B encodes a novel type of lycopene beta-cyclase, an enzyme that converts lycopene to beta-carotene. The amino acid sequence of B is similar to capsanthin-capsorubin synthase, an enzyme that produces red xanthophylls in fruits of pepper (Capsicum annum). Our results prove that beta-carotene is synthesized de novo during tomato fruit development by the B lycopene cyclase. In wild-type tomatoes B is expressed at low levels during the breaker stage of ripening, whereas in the Beta mutant its transcription is dramatically increased. Null mutations in the gene B are responsible for the phenotype in og, indicating that og is an allele of B. These results confirm that developmentally regulated transcription is the major mechanism that governs lycopene accumulation in ripening fruits. The cloned B genes can be used in various genetic manipulations toward altering pigmentation and enhancing nutritional value of plant foods.
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Affiliation(s)
- G Ronen
- Department of Genetics, The Life Sciences Institute, and Faculty of Agriculture, The Hebrew University of Jerusalem, Jerusalem, 91904 Israel
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294
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Mao L, Begum D, Chuang HW, Budiman MA, Szymkowiak EJ, Irish EE, Wing RA. JOINTLESS is a MADS-box gene controlling tomato flower abscission zone development. Nature 2000; 406:910-3. [PMID: 10972295 DOI: 10.1038/35022611] [Citation(s) in RCA: 245] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Abscission is a universal and dynamic process in plants whereby organs such as leaves, flowers and fruit are shed, both during normal development, and in response to tissue damage and stress. Shedding occurs by separation of cells in anatomically distinct regions of the plant, called abscission zones (AZs). During abscission, the plant hormone ethylene stimulates cells to produce enzymes that degrade the middle lamella between cells in the AZ. The physiology and regulation of abscission at fully developed AZs is well known, but the molecular biology underlying their development is not. Here we report the first isolation of a gene directly involved in the development of a functional plant AZ. Tomato plants with the jointless mutation fail to develop AZs on their pedicels and so abscission of flowers or fruit does not occur normally. We identify JOINTLESS as a new MADS-box gene in a distinct phylogenetic clade separate from those functioning in floral organs. We propose that a deletion in JOINTLESS accounts for the failure of activation of pedicel AZ development in jointless tomato plants.
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Affiliation(s)
- L Mao
- Clemson University Genomics Institute, South Carolina 29634, USA
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295
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Fridman E, Pleban T, Zamir D. A recombination hotspot delimits a wild-species quantitative trait locus for tomato sugar content to 484 bp within an invertase gene. Proc Natl Acad Sci U S A 2000; 97:4718-23. [PMID: 10781077 PMCID: PMC18299 DOI: 10.1073/pnas.97.9.4718] [Citation(s) in RCA: 212] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In nature, genetic variation usually takes the form of a continuous phenotypic range rather than discrete classes. The genetic variation underlying quantitative traits results from the segregation of numerous interacting quantitative trait loci (QTLs), whose expression is modified by the environment. To uncover the molecular basis of this variation, we characterized a QTL (Brix9-2-5) derived from the green-fruited tomato species Lycopersicon pennellii. The wild-species allele increased glucose and fructose contents in cultivated tomato fruits in various genetic backgrounds and environments. Using nearly isogenic lines for the QTL, high-resolution mapping analysis delimited Brix9-2-5 to a single nucleotide polymorphism-defined recombination hotspot of 484 bp spanning an exon and intron of a fruit-specific apoplastic invertase. We suggest that the differences between the Brix9-2-5 alleles of the two species are associated with a polymorphic intronic element that modulates sink strength of tomato fruits. Our results demonstrate a link between naturally occurring DNA variation and a Mendelian determinant of a complex phenotype for a yield-associated trait.
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Affiliation(s)
- E Fridman
- The Otto Warburg Center for Biotechnology, Faculty of Agriculture, Food and Environmental Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel
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296
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Molinero-Rosales N, Jamilena M, Zurita S, Gómez P, Capel J, Lozano R. FALSIFLORA, the tomato orthologue of FLORICAULA and LEAFY, controls flowering time and floral meristem identity. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 1999; 20:685-93. [PMID: 10652140 DOI: 10.1046/j.1365-313x.1999.00641.x] [Citation(s) in RCA: 154] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Characterization of the tomato falsiflora mutant shows that fa mutation mainly alters the development of the inflorescence resulting in the replacement of flowers by secondary shoots, but also produces a late-flowering phenotype with an increased number of leaves below first and successive inflorescences. This pattern suggests that the FALSIFLORA (FA) locus regulates both floral meristem identity and flowering time in tomato in a similar way to the floral identity genes FLORICAULA (FLO) of Antirrhinum and LEAFY (LFY) of Arabidopsis. To analyse whether the fa phenotype is the result of a mutation in the tomato FLO/LFY gene, we have cloned and analysed the tomato FLO/LFY homologue (TOFL) in both wild-type and fa plants following a candidate gene strategy. The wild-type gene is predicted to encode a protein sharing 90% identity with NFL1 and ALF, the FLO/LFY-like proteins in Nicotiana and Petunia, and about 80 and 70% identity with either FLO or LFY. In the fa mutant, however, the gene showed a 16 bp deletion that results in a frameshift mutation and in a truncated protein. The co-segregation of this deletion with the fa phenotype in a total of 240 F2 plants analysed supports the idea that FA is the tomato orthologue to FLO and LFY. The gene is expressed in both vegetative and floral meristems, in leaf primordia and leaves, and in the four floral organs. The function of this gene in comparison with other FLO/LFY orthologues is analysed in tomato, a plant with a sympodial growth habit and a cymose inflorescence development.
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Affiliation(s)
- N Molinero-Rosales
- Departamento de Biología Aplicada, Area de Genética, Universidad de Almería, 04120 Almería, Spain
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297
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Vallée B, Teyssier C, Maget-Dana R, Ramstein J, Bureaud N, Schoentgen F. Stability and physicochemical properties of the bovine brain phosphatidylethanolamine-binding protein. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 266:40-52. [PMID: 10542049 DOI: 10.1046/j.1432-1327.1999.00812.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The equilibrium behaviour of the bovine phosphatidylethanolamine-binding protein (PEBP) has been studied under various conditions of pH, temperature and urea concentration. Far-UV and near-UV CD, fluorescence and Fourier transform infrared spectroscopies indicate that, in its native state, PEBP is mainly composed of beta-sheets, with Trp residues mostly localized in a hydrophobic environment; these results suggest that the conformation of PEBP in solution is similar to the three-dimensional structure determined by X-ray crystallography. The pH-induced conformational changes show a transition midpoint at pH 3.0, implying nine protons in the transition. At neutral pH, the thermal denaturation is irreversible due to protein precipitation, whereas at acidic pH values the protein exhibits a reversible denaturation. The thermal denaturation curves, as monitored by CD, fluorescence and differential scanning calorimetry, support a two-state model for the equilibrium and display coincident values with a melting temperature Tm = 54 degrees C, an enthalpy change DeltaH = 119 kcal.mol-1 and a free energy change DeltaG(H2O, 25 degrees C) = 5 kcal.mol-1. The urea-induced unfolding profiles of PEBP show a midpoint of the two-state unfolding transition at 4.8 M denaturant, and the stability of PEBP is 4.5 kcal.mol-1 at 25 degrees C. Moreover, the surface active properties indicate that PEBP is essentially a hydrophilic protein which progressively unfolds at the air/water interface over the course of time. Together, these results suggest that PEBP is well-structured in solution but that its conformation is weakly stable and sensitive to hydrophobic conditions: the PEBP structure seems to be flexible and adaptable to its environment.
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Affiliation(s)
- B Vallée
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique, rue Charles Sadron, Orleans, Dijon, France
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298
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Abstract
Leaves are produced in succession on the shoot apical meristem (SAM) of a plant. The three landmark stages in leaf morphogenesis include initiation, acquisition of suborgan identities, and tissue differentiation. The expression of various genes relative to these steps in leaf morphogenesis is described. KNOTTED-like homeobox (KNOX) genes, FLO/LFY, and floral homeotic genes may be involved in generation of leaf shape and complexity. The differences between compound leaves and simple leaves in gene expression characteristics and morphogenetic patterns are discussed.
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Affiliation(s)
- Neelima Sinha
- Section of Plant Biology, Division of Biological Sciences, University of California at Davis, Davis, California 95616; e-mail:
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299
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Abstract
The overall morphology of an Arabidopsis plant depends on the behaviour of its meristems. Meristems derived from the shoot apex can develop into either shoots or flowers. The distinction between these alternative fates requires separation between the function of floral meristem identity genes and the function of an antagonistic group of genes, which includes TERMINAL FLOWER 1. We show that the activities of these genes are restricted to separate domains of the shoot apex by different mechanisms. Meristem identity genes, such as LEAFY, APETALA 1 and CAULIFLOWER, prevent TERMINAL FLOWER 1 transcription in floral meristems on the apex periphery. TERMINAL FLOWER 1, in turn, can inhibit the activity of meristem identity genes at the centre of the shoot apex in two ways; first by delaying their upregulation, and second, by preventing the meristem from responding to LEAFY or APETALA 1. We suggest that the wild-type pattern of TERMINAL FLOWER 1 and floral meristem identity gene expression depends on the relative timing of their upregulation.
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Affiliation(s)
- O J Ratcliffe
- Genetics Department, John Innes Centre, Colney Lane, Norwich, NR4 7UH, UK
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300
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Schmitz G, Theres K. Genetic control of branching in Arabidopsis and tomato. CURRENT OPINION IN PLANT BIOLOGY 1999; 2:51-5. [PMID: 10047573 DOI: 10.1016/s1369-5266(99)80010-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The patterns of axillary bud formation and the growth characteristics of side-shoots determine to a large extent the form of plants. Characterization of mutants in the monopodial plant Arabidopsis thaliana and in the sympodial tomato, as well as cloning of some of the respective genes, contributes to a better understanding of side-shoot development. Genes have been identified that influence the initiation of axillary meristems and the pattern of their subsequent development.
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Affiliation(s)
- G Schmitz
- Institut für Genetik Universität zu Köln Carl-von-Linné-Weg 10 D-50829 Köln Germany
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