Prof. Yaacov Okon

Research Interests:

Biological nitrogen fixation and plant promoting effects in associations between rhizophere bacteria and roots of grasses, legumes and vegetables. Biological nitrogen fixation in the Rhizobium legume symbiosis and bacterial diseases of plants.

Research Projects:

  • Improvement of nodulation, nitrogen fixation, water uptake and yield of chickpea (Cicer arietinum) and fava beans (Vicia faba). Funding: CRB Foundation 1996-2000
  • Extracellular factors involved in the aggregation of the N2-fixing rhizobacterium Azospirillum brasilense. Funding: ISF. 1998-2001
  • The regulation of the synthesis and degradation of the reserve material poly-β-hydroxybutyrate in Azospirillum brasilense. Funding: EU - 5th Framework. 2001-2003.
  • Molecular microbial ecology of populations in the rhizosphere: A study of cereals inoculated with Azosprillum brasilense. Funding: GIF; EU - 5th Framework. 2001-2003
  • Arabinose-rich exopolysaccharides (EPS) in Azospirillum brasilense. Funding: ISF (2005-2009).
 
See also: Yaacov Okon

Teaching

Teaching:

  • General Microbiology
  • Phytobacteriology
  • Biological Nitrogen Fixation
See also: Yaacov Okon

Members

Post-doc. Scholars:

  • Susana Castro-Sowinski
  • Angel Valverde-Portal

Present students:

  • Hila Kramer-Haimovich PhD student
  • Anat Lerner PhD student
  • Sharon Fibach PhD student
  • Anat Shtarker MSc student
See also: Yaacov Okon

Publications

Selected Publications:

Bahat-Samet E., Castro-Sowinski, S and Okon, Y. 2004.Arabinose content of extracellular polysaccharide plays a role in cell aggregation of Azospirillum brasilense. FEMS Microbiology Letters 237:195-203.

Kadouri, D., Castro-Sowinski, S., Jurkevitch, E. and Okon, Y. 2005. Ecological and agricultural significance of bacterialpolyhydroxyalkanoates. Critical Reviews in Microbiology 31:55-67.

Okon, Y. 2005. PGPR-technology cases of application and futureprospects. In Rhizosphere 2004-Perspectives and Challenges. A Tribute to Lorenz Hiltner. Hartmann, A., Schmid, M., Wenzel, W. and Hisinger, Ph. (eds.). GSF, Neuherberg pp 273-274.

Dobbelaere, S. and Okon, Y. 2005. The plant growth promoting effects and plant responses. In Nitrogen Fixation: Origins, Applications and Research Progress. Newton W. (Ed), Vol V: Associative and Endophytic Nitrogen-Fixing Bacteria and Cyanobacterial Associations. C. Elmerich and W. E. Newton. (eds) Springer, Heidelberg in press.

Moenne-Loccoz, Y., Woo, S.L., Okon, Y., Bally R., Lorito, L., Lemanceau, P. and Hartmann, A. 2005. Chapter 5. Free-living plant-beneficial microorganisms and soil quality in Microbiological Methods for Assessing Soil Quality- Plant-Microbes Interactions and Soil Quality, Bloem S., Hopkins, D.W. and Bennedeti A. (eds). CABI Publishing p. 368.

Herschkovitz, Y., Lerner, A., Davidov, Y., Rothballer, M., Hartmann, A. Okon, Y. and Jurkevitch, E. 2005. Inoculation with the plant growth promoting rhizobacterium Azospirillum brasilense causes little disturbance in the rhizosphere and rhizoplane of maize (Zea mays). Microbial Ecology 50:277-288.

Herschkovitz, Y., Lerner, A., Davidov, Y., Okon, Y. and Jurkevitch, E. 2005. Azospirillum brasilense does not affect population structure of specific rhizobacterial communities of inoculated maize (Zea mays). Environmental Microbiology. 7:1847-1852.

Lerner, A., Herschkovitz, Y., Baudoin, E., Nazaret, S., Moenne-Loccoz, Y., Okon, Y., and Jurkevitch, E. 2006. Effect of Azospirillum brasilense on rhizobacterial communities analyzed by denaturing gradient gel electrophoresis and automated intergenic spacer analysis. Soil Biology and Biochemistry on line.

Lerner, A., Shor, Y., Vinokurov, A., Okon, Y. and Jurkevitch, E. 2006. Can denaturing gradient gel electrophoresis (DGGE) analysis of amplified 16S rDNA of soil bacterial populations be used in forensic investigations? Soil Biology and Biochemistry on line

Kramer-Haimovich, H., Servi, E., Katan, T., Rollins, J., Okon, Y. and Prusky, D. 2006. Effect of ammonia production by C. gloeosporioides on pelB activation, pectate lyase secretion and fruit pathogenicity. Applied and Environmental Microbiology. In press

Lerner, A., Herschkovitz, Y., Baudoin, E., Nazaret, S., Moenne-Loccoz, Y., Okon, Y., and Jurkevitch, E. 2006. Effect of Azospirillum brasilense on rhizobacterial communities analyzed by denaturing gradient gel electrophoresis and automated intergenic spacer analysis. Soil Biology and Biochemistry 38:1212-1218.

Lerner, A., Shor, Y., Vinokurov, A., Okon, Y. and Jurkevitch, E. 2006. Can denaturing gradient gel electrophoresis (DGGE) analysis of amplified 16S rDNA of soil bacterial populations be used in forensic investigations? Soil Biology and Biochemistry 38:1188-1192.

Kramer-Haimovich, H., Servi, E., Katan, T., Rollins, J., Okon, Y. and Prusky, D. 2006. Effect of ammonia production by C. gloeosporioides on pelB activation, pectate lyase secretion and fruit pathogenicity. Applied and Environmental Microbiology. 72:1034-1039.

Valverde, A., Okon, Y. and Burdman S. 2006. cDNA-AFLP reveal differentially expressed genes related to cell aggregation in Azospirillum brasilense. FEMS Microbiology Letters 265:186-194.

Dobbelaere, S. and Okon, Y. 2007. The plant growth promoting effects and plant responses. In Nitrogen Fixation: Origins, Applications and Research Progress. Newton W. (Ed), Vol V: Associative and Endophytic Nitrogen-Fixing Bacteria and Cyanobacterial Associations. C. Elmerich and W. E. Newton. (eds) Springer, Heidelberg pp 145-170.

Castro-Sowinski S., Matan, O., Bonafede, P. and Okon, Y. 2007. A thioredoxin of Sinorhizobiummeliloti CE52G is required for melanin production and symbiotic nitrogen fixation. Molecular Plant-Microbial Interactions 20:986-993.

Castro-Sowinski S., Herschkovitz, Y., Okon, Y. and Jurkevitch, E. 2007. Effects of inoculation with plant growth-promoting rhizobacteria on resident rhizosphere microorganisms. FEMS Microbiology Letters 276:1-11.

Dardanelli, M.S., Rodrguez Navarro, D.N., Megas, M., Okon, Y., 2008. Influencia de la coinoculacin Azospirillum-rizobiossobre el crecimiento y la fijacin de nitrgeno de leguminosas de inters agronmico. In: Cassn, F.,Garca Salamone, I. (Eds.), Azospirillum sp: Cell physiology, Plant Response, Agronomic and Environmental Research in Argentina,Asociacin Argentina de Microbiologa, pp. 143-153.

Dardanelli, M. S., Fernandez de Cordoba, F. J., Espuny, M. R., Rodriguez Carvajal M. A., Soria Diaz M. E, Gil Serrano, A., Okon, Y. and Megias, M. 2008. Effect of Azospirillum brasilense coinoculated with Rhizobiumon Phaseolus vulgaris flavonoids and Nod factor production under salt stress. Soil Biology and Biochemistry 40:2713-2721.

Valverde, A., Castro-Sowinski, S., Lerner, A., Fibach, S., Matan, O., Burdman, S. and Okon, Y. 2008. Exopolysaccharide production and cell aggregation in Azospirillum brasilense. In F. D. Dakora et al., (eds.), Biological Nitrogen Fixation:Towards Poverty Alleviation Through Sustainable Agriculture. Springer Science. pp 319-320.

Castro-Sowinski, S., Matan, O., Star, L. and Okon, Y. 2008. Thiol-redox potential in melanin production and nitrogen fixation by Sinorhizobiummeliloti. In F. D. Dakora et al., (eds.), Biological Nitrogen Fixation:Towards Poverty Alleviation Through Sustainable Agriculture. Springer Science. pp 373.

Lerner, A., Okon, Y. and Burdman, S. 2009 The wzm gene located in the pRhico plasmid of Azospirillum brasilense Sp7 is involved in lipopolysaccharide synthesis. Microbiology 155:791-804.

Spaepen, S., Vanderleyden, J. and Okon, Y. 2009.Plant growth-promoting actions of rhizobacteria. Advances in Botanical Research 51:283-320.

Lerner, A., Castro-Sowinski, S., Lerner, H., Okon, Y. and Burdman, S. 2009. Glycogen phosphorylase is involved in stress endurance and biofilm formation in Azospirillum brasilense Sp7. FEMS Microbiology Letters 300:75-82.

Lerner, A., Castro-Sowinski, S., Valverde, A., Lerner, H., Dror, R., Okon, Y. and Burdman, S. 2009. The Azospirillum brasilense Sp7 noeJ and noeL genes are involved in extracellular polysaccharide biosynthesis. Microbiology 155:4058-4068.

Castro-Sowinski, S. Burdman, S., Matan, O. and Okon, Y. 2010. Functions of PHA in the environment in Chen G-Q Edt. Plastics from Bacteria: Natural Functions and Applications. Microbiology Monographs (book series) Vol.14 Springer-Verlag Berlin Heidelberg pp 39-61.

Baudoin, E., Lerner, A., Mirza, M. S., El Zemrany, H., Prigent-Combaret, C., Jurkevich, E., Spaepen, S., Vanderleyden, J., Nazaret, S., Okon, Y. and Monne-Loccoz, Y. 2010. Effects of Azospirillum brasilense PGPR genetically modified with auxin production gene ipdC on the diversity of the indigenous microbiota of the wheat rhizosphere. Research in Microbiology 161:219-226.

Lerner, A., Valverde, A., Castro-Sowinski, S., Lerner, H., Okon, Y. and Burdman, S. (2010). Phenotypic variation in Azospirillum brasilense exposed to starvation. Environmental Microbiology Reports 2:577-586.

Medeot, D. B., Paulucci, N. S, Albornoz, A., Fumero, M. V., Bueno, M., Garcia, M.B., Woelke, M., Okon, Y. and Dardanelli, M. S. 2010. Plant growth promoting rhizobacteria improving the legume-rhizobia symbiosis in M.S. Khan et al. (eds.), Microbes for Legume Improvement, Chapter 19. Springer-Verlag/Wien.

See also: Yaacov Okon