Prof. Issac Barash
Ph.D.: University of California, Davis, U.S.A, 1965
Phone:

(Office): +972-3-640-9847
(Home) +972-3-5409441
(Fax): +972-3-640-9380
E-mail: isaaci@post.tau.ac.il
Room#: Britania bldg. room 514
Member's portrait

Personal Information
I.Home Adress
27 Sayfan st., Ramat Hasharon, 47248, Israel
 
II. Education
1956-1961 The Hebrew University of Jerusalem,
1961 - M.Sc. in Plant Protection (with distinction)
1961-1965 University of California, Davis, U.S.A.
1965 - Ph.D. in Plant Pathology (Biochemistry minor)
 
III. Memberships

American Phytopathological Society (APS Fellow).
International Society for Molecular Plant - Microbe Interactions
Israeli Phytopathological Society
International Society for Plant Molecular Biology

 
IV. Research Grants (last decade)
  1. Role of Thaxtomins in the pathogenicity of Streptomyces spp. on potato. BARD, The US-Israel Binational Agricultural Research and Development, 1992.
  2. Role and in situ regulation of growth regulators in tumor production by Erwinia herbicola on Gypsophila paniculata. BARD, 1992-1995.
  3. Biological control of the greenhouse and sweetpotato whiteflies by entomopathogenic fungi. AID-CDR, 1993-1994.
  4. Relationship of genes conferring epiphytic fitness and internal multiplication in plants in Erwinia herbicola. BARD, 1995-1998.
  5. The role of proteins secreted via the hrp gene cluster in pathogenicity of Erwinia herbicola pv. gypsophilae and Erwinia stewartii BARD, 1998-2000.
  6. The Molecular Basis for Pathogenicity of Clavibacter michiganensis subsp. miciganensis and Erwinia herbicola pathovars gypsophilae and betae. Supported by DFG (Germany) for trilateral cooperative research between Israeli, Palestinian and German Scientists (1998-2003).
  7. Advanced detection methods for control of plant bacterial pathogens USAID-CDR (U.S.A.), 1997-2001.
  8. Insect pest management with fungi: A mass production technique for farmers USAID-CDR, 1999-2002.
  9. The roles of hrp-dependent effector proteins and hrp gene regulation as determinants of virulence and host specificity in Erwinia stewartii and E. herbicola. BARD, 2001-2004
  10. Molecular basis for transformation of an epiphyte into a plant pathogen as exemplified
    by Erwinia herbicola pvs. gypsophilae and betae. Israel Science Foundation 2001-2004.

Research Interests

My scientific intersts throughout the years have been aimed at biochemical and molecular aspects of plant-microbe interactions, primarily on bacterial and fungal plant pathogens. During the last decade I have mainly focused on the molecular genetics of virulence in the plant-pathogenic bacterium Pantoea agglomerans (previously known as Erwinia herbicola). This research was carried out in collaboration with Dr. Shulamit Manulis of the Dept. of Plant Pathology, A.R.O., The Volcani Center. P. agglomerans is widespread in nature as an epiphyte on diverse plants as well as a saprophyte in numerous habitats. However, some strains have evolved into gall-forming bacteria on beet, gypsophila and other plants. Thus P. agglomerans pv. gypsophilae incites galls only on gypsophila whereas P. agllomerans pv. betae is pathogenic on beet and gypsophila. Our main efforts are aimed at understanding the molecular determinants, which causes P. agglomerans to “switch” from an epiphyte on numerous plants into gall-forming host-specific pathogen. We discovered that all the pathogenic strains of the gypsophila and beet pathovars respectively harbor a pathogenicity plasmids designated as pPATHPag and pPATHPab. pPATHPag, that was more extensively studied, has a size of approximately 150-kb and appears to accommodate a putative pathogenicity island of more than 70-kb. Many genes associated with virulence including hrp gene cluster, genes encoding type III virulence effectors and genes encoding enzymes for IAA and cytokinin biosynthesis were characterized on the pPATHPag. In addition the pathogenicity plasmids of both pathovars harbor numerous copies of insertion sequences representing five different families. Current research is aimed at answering the following questions: What is the complete inventory of virulence type III effectors delivered through the Hrp system into plant cells by Pag and Pab? What are the genes responsible for host specificity on gypsophila or beet? How the virulence effectors are being regulated? How do they interact with intracellular host plant components to elicit gall formation? What are the plant growth regulators triggered by type III effectors is the share of hrp-independent virulence genes in pathogenicity of Pag or Pab?

Recently we have identified the presence of a quorum sensing (QS) system in P. agglomerans. This bacterium produces C4-homoserine lactone (C4-HL) as the predominant cognate signal. The biosynthetic gene (luxI equivqlent) has already been cloned and the LuxR equivalent and target genes are being search for. The role of QS system in endophytic growth and virulence is currently being investigated.

Specific topics:
Topic 1; Molecular mechanisms of virulence in phytopathogenic bacteria.
Topic 2; The role of quorum sensing in plant-bacteria interactions.

Selected Publications

Recent Publications(Out of over 100 publications in refereed journals and books)
  1. Lichter, A., S. Manulis,O. Sagee, Y. Gafni, J. Gray, R. Meilen R. O. Morris, I. Barash. 1995. Production of cytokinins by Erwinia herbicola pv. gypsophilae and isolation of a cytokinin biosynthetic gene. Mol. Plant Microb. Interact 8: 114-121.
  2. Dori, S., Z. Solel, I. Barash. 1995. Cell wall-degrading enzymes produced by Gaeumannomyces graminis var.tritici in vitro and in vivo. Physiological and Molecular Plant Pathology 46: 189-198..
  3. Lichter, A., I. Barash, L. Valinsky S. Manulis. 1995. The genes involved in cytokinin biosynthesis in Erwinia herbicola pv. gypsophilae: characterization and role in gall formation. J. Bacteriol. 177: 4457-4465.
  4. Lichter, A., S. Manulis, L. Valinsky, B. Karniol, I. Barash. 1996. IS1327, a new insertion element in the pathogenicity-associated plasmid of Erwinia herbicola pv. gypsophilae. Mol. Plant. Microb. Interactions 9: 98-104.
  5. Mor, H., G. Gindin, I.S. Ben Zeev, B. Raccah, N.V. Geschtout, N. Ajtkehozhina, I. Barash. 1996. Diversity among isolates of Verticillium lecanii as expressed by DNA polymorphism and virulence towards Bemisia tabaci. Phytoparasitica 24: 111-118.
  6. Gindin,G., I. Barash, B. Raccah,I.S. Ben-Ze'ev, M. Klein. 1996. The potential of some entomopathogenic fungi as biocontrol agents against the onion thrips, Thrips tabaci and the western flower thrips, Frankliniella occidentalis. Folia Entomologica Hungarica 37:37-42.
  7. Nizan, R., I. Barash, L. Valinski, A. Lichter, S. Manulis. 1997. The presence of hrp genes on the pathogenicity-associated plasmid of the tumorigenic bacterium Erwinia herbicola pv. gypsophilae.Mol. Plant Microbe Interactions. Mol. Plant Microb. Interact.10:677-682.
  8. Gafni,Y.,S. Manulis, T. Kunik, A. Lichter, I. Barash, Y. Ophir. 1998. Characterization of auxin synthesis genes of Erwinia herbicola pv. gypsophilae. Isr. J. Plant Sci. 45-279-284.
  9. Valinsky, L.,Manulis, S., Ezra, D., Nizan, R., I. Barash. 1998. A pathogenicity gene isolated from the pPATH of Erwinia herbicola pv. gypsophilae determines host specificity. Mol. Plant Microbe. Interact. (11:753-762).
  10. Manulis, S., A. Haviv-Chesner, M. T. Brandl, S. E. Lindow, I. Barash. 1998. Differential involvement of indole-3-acetic acid biosynthetic pathways in pathogenicity and epiphytic fitness of Erwinia herbicola pv. gypsophilae Mol. Plant Microbe Interact. (11:634-642).
  11. Ezra, D. Barash, I., Valinsky, L. S. Manulis 2000. The dual function in virulence and host-range restriction of a gene isolated from pPATHEhg plasmid of Erwinia herbicola pv. gypsophilae. Mol. Plant-Microbe Interact. 13:683-692.
  12. Gindin, G., Geschtovt N.U., Raccah, B, I. Barash. 2000. Pathogenicity of Verticillium lecanii to different developmental stages of Bemisia tabaci. Phytoparasitica 28:229-239.
  13. Mor, H., Manulis, S., Zuc, M., Nizan, R., Coplin, D. L., I. Barash 2001. Genetic organization of the hrp gene cluster and dspEF operon in Erwinia herbicola pv. gypsophilae., Molec. Plant-Microbe Interact. 14: 431-436..
  14. Guo, M, Manulis, S., Barash, I.., and Lichter, A. (2001). The operon for cytokinin biosynthesis of Erwinia herbicola pv. gypsophilae contains two promoters and is plant induced. Can. J. of Microbiology 47: 1126-1131.
  15. Valinsky, L., Barash, I., Chalupowicz, L., Ezra, D., S. Manulis. 2002. Regulation of HsvG, a host specific virulence gene of Erwinia herbicola pv. gypsophilae. Physiological and Molecular Plant Pathology 60:19-29.
  16. Guo, M., Manulis, S., Mor, H., I. Barash 2002. The presence of diverse IS elements and avrPphD homologue that acts as a virulence factor on the pathogenicity plasmid of Erwin herbcola pv. gypsophila. Molec. Plant-Microbe Interact 15:709-716.
  17. Valinsky, L., Nisan, I., Tu, X., Nisan, G., Rosenshine, I., Hanski, E., Barash, I., S. Manulis 2002. A host-specific virulence protein of Erwinia herbicola pv. gypsophilae is translocated into human epithelial cells by the type III secretion system of enteropathogenic Escherichia coli. Molec. Plant Pathol. 3:97-101.
  18. Nizan-Koren, R., Manulis, S., Mor, H., Iraki, N. M., I. Barash. 2003. The regulatory cascade that activates the Hrp regulon in Erwinia herbicola pv. gypsophilae. Molec. Plant-Microbe Interact 16:249-260.
  19. Manulis, S. and I. Barash. 2003. The molecular basis for transformation of an epiphyte into a gall-forming pathogen as exemplified by Erwinia herbicola pv. gypsophilae, (Stacey, G. and Keen, Nקגדץlant-Microbe Interactions 6:19-52
  20. Manulis, S. and I. Barash. 2003. Pantoea agglomerans pvs. gypsophilae and betae, a recently-evolved pathogens? Molecular Plant Pathology 20:307-314.
  21. Manulis, S. and I. Barash. 2003. Contribution of virulence determinants from Pseudomonas and other bacteria to hrp-dependent gall formation by Erwinia herbicola pv. gypsophilae. In: Pseudomonas syringae and related pathogens. N. S. Iacobellis (ed.). Kluwer Academic Publishers (in press).

Students
Fifteen graduate students for Ph.D. degree and more than 32 for M.Sc. degree have completed or are about to complete, their research in my laboratory during the last 20 years.

Courses

I have taught the following courses during the past 20 years :

  1. Physiology of Fungi.
  2. Biology of Plant Pathogenic bacteria and Fungi.
  3. Molecular Plant-Microbe Interactions (graduate course)
  4. Molecular aspects of pathogenicity and symbiosis in plant-bacteria interactions
Enter here specific template content