Welcome to the home page of the laboratory of

Avraham A. Levy

Associate Professor

Ph.D. Weizmann Institute of Sciences, Rehovot Israel
B.Sc and M.Sc. Faculty of Agriculture, Hebrew University of Jerusalem, Israel


 2nd MEETING OF THE ISRAELI GRAMINEAE CONSORTIUM 
January 1st 2006

Weizmann Institute of Science, Schmidt Lecture hall
Poster     Program 

Telephone: 972 8 9342734 (work)
                 972 8 9344205 (home)
Fax: 972 8 9344181
           


E-mail: avi.levy@weizmann.ac.il
       

Research interests: The Dynamic plant genome

The Levy laboratory is investigating mechanisms which are responsible for the rapid evolution of plant genomes. This includes transposons, DNA double-strand break repair, via homologous or non-homologous recombination, and polyploidy-induced DNA rearrangements. Moreover, we are developing tools for forward and reverse genetics, based on the Ac/Ds transposons; on homologous recombination, and on EMS and fast-neutron mutagenesis.

Transposons
We are focusing on the Ac/Ds elements; on their origin, on their regulation and on the intermediates of transposition.

DSB repair
We have studied the repair of DSBs generated by transposons, and we showed that these breaks can be repaired by homologous recombination between ectopic sequences. We have studied the repair of breaks done in vitro and characterized the end joining products. In general, we found the DSB repair in plants is error-prone. Accurate repair via homologous recombination is a less prominent DSB repair pathway in plants than non-homologous end-joining.

Polyploidy-induced DNA rearrangements
We have shown, in collaboration with Prof. Moshe Feldman, that certain DNA sequences that were isolated by microdissection of wheat chromosomes undergo rapid elimination as a result of polyploidy. We are currently investigating the underlying mechanism of this polyploidy-induced sequence elimination.

Genetic tools
We have developed a miniature tomato cultivar with a rapid growth cycle as a model system for forward and reverse genetics in tomato (Meissner et al., 1997; Meissner et al. 2000). We are using this cultivar for large scale mutagenesis via transposon, EMS andfast-neutron. This work was initiated under the auspices of the Israeli plant genome center. We have shown that the bacterial genes, RuvC stimulates homologous recombination in plants. We have isolated hyper-recombinogenic mutants and we are testing whether these mutants and plants expressing bacterial genes can be used for improving the efficiency of gene targteting.
 
 

Lab members, present and past:

Technicians

Naomi Avivi Ragolsky, 1992-present

Postdocs

Dr. Yaron Sitrit 1996-1998

Dr. Veronique Chague 1997-2000

Dr. Qian-Ho Zhu 1998-1999

Dr. Neta Holland 1995-1996

Dr. Yoav Barak     2000-present

Ph.D. Students

Dr. Marcelo Fridlender 1992-1997

Dr. Gil Shalev 1992-1997

Dr. Eitan Rubin 1994-1999

Dr. Vera Gorbunova 1995-1999

Dr. Rafi Meissner 1995-1999, (Co-supervised with Prof. Y. Elkind)

Shai Levyatuv 1997-present, (Co-supervised with Prof. Y. Elkind)

Sharon Ayal  PhD student 1999-present (Co-adviser with Prof. M. Feldman, Weizmann Inst.)

Khalil Kaskush  PhD student 1999-present (Co-adviser with Prof. M. Feldman Weizmann Inst.)

M.Sc. Students

Vera Gorbunova 1994-1995

Sarah Melamed 1996-1998, (Co-supervised with Prof. A. Ashri)

Ilia Rochlin 1998-1999

Eyal Emmanuel  M.Sc.   1999-present

Hezi Shaked  M.Sc.   1999-present

Gila Lithwick  M.Sc.   1999-present

Reviewed Publications

  1.     Pinthus, M. J., and A. A. Levy. 1983. The relationship between Rht1 and Rht2 dwarfing genes and grain weight in Triticum aestivum L. spring wheat. Theor. Appl. Genet. 66: 153-157.

  2.     Pinthus, M. J., and A. A. Levy. 1984. Genotypic effects of height on grain yield of Triticum aestivum L. spring wheat. Z. Pflanzenzuchtung. 93: 49-55.

  3.     Millet, E., A. A. Levy, L. Avivi, R. Zamir, and M. Feldman. 1984. Evidence for maternal effect in the inheritance of grain protein in crosses between cultivated and wild tetraploid wheats. Theor. Appl. Genet. 67: 521-524.

  4.     Levy, A. A., G. Galili, and M. Feldman. 1985. The effect of additions of Aegilops longissima chromosomes on grain protein in common wheat. Theor. Appl. Genet. 69:429-435.

  5.     Levy, A. A., and M. Feldman. 1985. Genotypic and fertilization effects on grain protein content in wild and cultivated tetraploid wheats. Genetica Agraria 39: 293-302.

  6.     Galili, G., A. A. Levy, and M. Feldman. 1986. Gene dosage compensation of endosperm proteins in hexaploid wheat Triticum aestivum. Proc. Natl. Acad. Sci. USA 83: 6524-6528.

  7.     Levy, A. A., and M. Feldman. 1987. Increase of grain protein percentage in high-yielding common wheat breeding lines by genes from wild tetraploid wheat. Euphytica 36: 353-359.

  8.     Levy, A. A., and M. Feldman. 1988. Ecogeographical distribution of HMW glutenin alleles in populations of the wild tetraploid wheat Triticum turgidum var. dicoccoides. Theor. Appl. Genet. 75:651-658.

  9.     Levy, A. A., G. Galili, and M. Feldman. 1988. Polymorphism and genetic control of high molecular weight glutenin subunits in wild tetraploid wheat. Heredity 61: 63-72.

  10.     Levy, A. A., D. Braun, and M. Feldman. 1988. Evaluation of the contribution of alien chromosomes to quantitative traits in common wheat. Genome 30: 265-268.

  11.     Manisterski, J., A. Segal, A. A. Levy, and M. Feldman. 1988. Evaluation of Israeli Aegilops and Agropyron species for resistance to wheat leaf rust. Plant Disease 72: 941-944.

  12.     Levy, A. A., and M. Feldman. 1989. Location of genes for high grain protein percentage and other quantitative traits in wild wheat Triticum turgidum var. dicoccoides. Euphytica 41: 113-122.

  13.     Levy, A. A., and M. Feldman. 1989. Intra and inter-population variations in grain protein percentage in wild tetraploid wheat, Triticum turgidum var. dicoccoides. Euphytica 42: 251-258.

  14.     Levy, A. A., and M. Feldman. 1989. Genetics of morphological traits in wild wheat, Triticum turgidum var. dicoccoides. Euphytica 40: 275-281.

  15.     Levy, A. A., Bagg Britt, A., K. R. Luehersen, V. L. Chandler, C. Warren, and V. Walbot. 1989. Developmental and genetic aspects of Mutator excision in maize. Developmental Genetics 10: 520-531.

  16.     Levy, A. A., and V. Walbot. 1990. Regulation of the timing of transposable element excision during maize development. Science 248: 1534-1537.

  17.     Levy, A. A., and V. Walbot. 1991. Molecular analysis of the loss of somatic instability in the bz2::mu1 allele of maize. Mol. Gen. Genet. 229: 147-151.

  18.     Levy, A. A., C. Andre, and V. Walbot. 1991. Analysis of a 120 kb mitochondrial chromosome in maize. Genetics 128: 417-424.

  19.     Felsenburg, T., A.A. Levy, G. Galili, and M. Feldman. 1991. Polymorphism of high-molecular-weight glutenins in wild tetraploid wheat: Spatial and temporal variation in a native site. Isr. J. of Bot. 40:501-508.

  20.     Andre, C., A. A. Levy, and V. Walbot. 1992. Small repeated sequences and the structure of plant mitochondrial genomes. Trends in Genetics 8: 128-132.

  21.     Vega, J. M., S. Abbo, M. Feldman, and A. A. Levy. 1994. Chromosome painting in plants: In situ hybridization with a DNA probe from a specific microdissected chromosome arm of common wheat. Proc. Natl. Acad. Sci. USA 91: 12041-12045.

  22.     Fridlender, M., K. Harrison, J. D. G. Jones, and A. A. Levy. 1996. Repression of the Ac transposase gene promoter by Ac transposase. Plant Journal 9: 911-917.

  23.     Levy, A. A., M. Fridlender, U. Hanania, E. Rubin, and Y. Sitrit. 1996. Binding of Nicotiana nuclear proteins to the subterminal regions of the Ac transposable element. Mol. Gen. Genet. 251: 436-441.

  24.     Rubin, E., and A. A. Levy. 1996. A Mathematical model and a computerized simulation of PCR using complex templates. Nucl. Acids Res. 24: 3538-3545.

  25.     Fridlender, M., S. Lev-Yadun, I. Baburek, K. Angelis, and A. A. Levy. 1996. Cell divisions in cotyledons after germination: localization, time course and utilization for a mutagenesis assay. Planta 199: 307-313.

  26.     Gorbunova, V., and A. A. Levy. 1997a. Circularized Ac/Ds transposons: formation, structure and fate. Genetics 145: 1161-1169.

  27.     Shalev, G., and A. A. Levy. 1997. The maize transposable element Ac induces recombination between the donor site and an homologous ectopic sequence. Genetics 146: 1143-1151.

  28.     Baburek, I., B. Stiburkova, A. , L. Vrba,  A. Levy, and K. J. Angelis. 1997. Tobacco cotyledons: A novel system for testing mutagenicity in plants. (Proceedings: Czech-Taiwan Symposium on Biotechnology, 1995., pp. 101-104).  Environmental and Molecular Mutagenesis 30: 91-93.

  29.     Rubin, E., and A. A. Levy. 1997. Abortive gap repair: The underlying mechanism for Ds element formation. Mol. Cell. Biol. 17: 6294-6302.

  30.     Feldman, M., B. Liu, G. Segal, S. Abbo, A. A. Levy, and J. M. Vega. 1997. Rapid elimination of low copy DNA sequences in polyploid wheat: a possible mechanism for differentiation of homoeologous chromosomes. Genetics 147: 1381-1387.

  31.     Gorbunova, V., and A. A. Levy. 1997b. Nonhomologous DNA end joining in plant cells is associated with deletions and filler DNA insertions. Nucl. Acid Res. 25: 4650-4657

  32.     Meissner, R., Y. Jacobson, S. Melamed, S. Levyatuv, G. Shalev, A. Ashri, Y. Elkind, and A. A. Levy. 1997. A new model system for Tomato Genetics. Plant J. 12: 1465-1472

  33.     Fridlender, M., Y. Sitrit, O. Shaul, O. Gileadi, and A. A. Levy. 1998. Analysis of the Ac promoter: structure and regulation. Mol. Gen. Genet., 258: 306-314.

  34.     Shalev, G., Y. Sitrit, N. Avivi-Ragolski, C. Lichtenstein, and A.A. Levy. 1999 Stimulation of homologous recombination in plants by expression of the bacterial resolvase RuvC. Proc. Natl. Acad. Sci. 96:7398-7402.

  35.     Gorbunova, V. and Levy A.A. 1999. How plants make ends meet: DNA double-strand break repair. Trends in Plant Sciences 4:263-269.

  36.     Gorbunova, V. and Levy A.A. 2000. Analysis of extrachromosomal Ac/Ds transposable element. Genetics 155:349-359.

  37.     Meissner, R., V. Chague, Q. Zhu, Y. Elkind, E. Emmanuel, and Levy A.A. 2000. A high throughput system for transposon tagging and promoter trapping in tomato. Plant Journal 22:265-274.

  38.     Gorbunova, V., Ramos, C., Hohn, B., and Levy A.A. 2000. A nuclear protein that binds specifically to several maize transposins is not essential for Ds1 excision. Mol. Gen. Genet. 263:492-497.

  39.     Gorbunova, B., Avivi-Ragolski, N., Shalev, G., Kovalchuk, I., Abbo, S., Hohn B and Levy, A.A. 2000. A new hyperrecombinogenic mutant of Nicotiana tabacum. The Plant Journal 24: 601-611.

  40.     Rubin, E., Lithwick, G., and Levy A.A. 2001. Structure and evolution of the hAT transposon superfamily. Genetics 158: 949-957.

  41.     Shaked, H., Kashkush, K., Ozkan, H., Feldman, M., and Levy A. A. 2001. Sequence elimination and cytosine methylation are rapid and reproducible responses of the genome to wide hybridization and allopolyploidy in wheat. The Plant Cell, 13:1749-1759.

  42.     Ozkan, H., Levy A. A. and Feldman, M. 2001. Alloploidy-induced rapid genome evolution in the wheat (Aegilops-Triticum) group. The Plant Cell, 13:1735-1747.

  43.     Hohn, B., Levy, A.A. and Puchta, H. 2001. Elimination of selection markers from transgenic plants. Current Opinion in Biotechnology 12: 139-143.

  44.     David-Schwartz, R., Badani, H., Wininger, S., Levy, A.A., Galili, G. and Kapulnik Y. 2001. Identification of a novel genetically controlled step in mycorrhizal colonization: plant resistance to infection by fungal spores but not extra-radical hyphae. The Plant Journal, 27:561-569.

  45.     Kashkush, K., Feldman, M., and Levy A.A. 2002. Gene loss, silencing, and activation in a newly-synthesized wheat allotetraploid. Genetics 160:1651-1659.

  46.     Emmanuel, E. and Levy A.A. 2002. Tomato mutants as tools for functional genomics. Current Opinion in Plant Biology, 5:112-117.

  47.     Feldman, M. and Levy A.A. 2002. The impact of polyploidy on grass genome evolution. Plant Physiology, 130: 1587-1593

  48.     Kashkush, K. Feldman, M. and Levy A.A. 2003. Transcriptional activation of retrotransposons alters the expression of adjacent genes in wheat. Nature Genetics, 33:102-106