Dhirendra Kumar, Ph.D.

     Assistant Professor  

     Department of Biological Sciences,

     Box 70703,            

     East Tennessee State University, Johnson city, TN 37614-1710

     Phone :  (423) 439-6928         Fax: (423) 439-5958

     email :    kumard@etsu.edu

RESEARCH

Our lab is interested in studying the salicylic acid (SA) mediated defense signaling in plants. SA) mediated pathway is one of the major pathways by which plants defend themselves. Plants resisting pathogen attack produce high amounts of salicylic acid which leads to activation of defense pathways. How the SA activates defense signaling pathways? is unclear. Using biochemical approach we identified a 29 kDa protein, salicylic acid binding protein 2 (SABP2) which binds SA with high affinity (KD=~90 nM). SABP2 is a esterase which converts the inactive methyl salicylate (MeSA) to the active salicylic acid. High levels of MeSA is produced in the plants resisting pathogen attack. Three dimensional structure analysis of SABP2 in complex with SA shows that SA binds in the active site of the SABP2. This binding inhibits the enzymatic activity of SABP2 which stops the conversion of MeSA to SA. Plants continue to make MeSA which is not only travels to other parts of the plant but also to neighboring plants. SABP2 in the healthy parts of the plant catalyzes the conversion of MeSA into SA which turns on the defense pathway and plant exhibits systemic acquired resistance (SAR). RNAi-mediated silencing of SABP2 in tobacco rendered the plant more susceptible to pathogen attack and it lost its ability to mount the systemic acquired resistance (SAR) response. These RNAi plants were also compromised in expression of defense genes. Our recent studies suggest that methyl salicylate is the long sought mobile signal for plant innate immunity which the scientists have been searching for more that five decades (http://www.sciencemag.org/cgi/content/summary/sci;318/5847/31a).

Publications 

   Vlot, Corina., Liu, Po-Pu, Cameron, R.K., Park, S.W., Yang,Y., Kumar, D., Zhou, F., Paddukavidana, T., Gustafsson, C., Pichersky, E. and     Klessig, D.F. (2008) Identification of likely orthologs of tobacco salicylic acid-binding protein 2 and their role in systemic acquired resistance in Arabidopsis thaliana. The Plant Journal. vol 56(3):445-56 http://www3.interscience.wiley.com/cgi-bin/fulltext/120747256/PDFSTART

Kumar, D. and Klessig, D.F. (2008) The search for the salicylic acid receptor led to discovery of the SAR signal receptor. Plant Signaling & Behavior vol 3 (9) 689-690 http://www.landesbioscience.com/journals/psb/article/5844

Park, S.W., Kumar, D., Kaimoyo, E., Vlot, A.C., and Klessig, D.F. (2008) The roles of salicylic acid-binding protein 2 and methyl salicylate in systemic acquired resistance in tobacco and Arabidopsis. In “Biology of Plant Microbe Interactions”, edited by F. Sánchez, C. Quinto I.M. López-Lara and O. Geiger, IS-MPMI, St Paul, MN. Vol-6.

   Park, S.-W., Kaimoyo, E., Kumar, D., Mosher, S., and Klessig, D. F. (2007) Methyl Salicylate is a Critical Mobile Signal for Plant Systemic Acquired Resistance. Science, vol 318 no. 5: 113-116. http://www.sciencemag.org/cgi/content/abstract/318/5847/113

   Salicylic acid binding protein (SABP)2 and Systemic Acquired Resistance (2007). In “Biology of Plant Microbe Interactions”, edited by F. Sánchez, C. Quinto I.M. López-Lara and O. Geiger, IS-MPMI, St Paul, MN. 5:176-181.

   Kumar D., Gustafsson C. and Klessig, D.F. (2006) Validation of RNAi silencing specificity using synthetic genes: Salicylic acid binding protein 2 is required for innate immunity in plants. The Plant Journal 45: 863-868 http://www.blackwell-synergy.com/doi/pdf/10.1111/j.1365-313X.2005.02645.x

   Menke FL, Kang H.G., Chen Z., Park, J.M., Kumar, D. and Klessig, D.F. (2005) Tobacco transcription factor WRKY1 is phosphorylated by the MAP kinase SIPK and mediates HR like cell death in tobacco. Mol. Plant-Microbe Interact. 18: 1027-34. http://www.apsnet.org/mpmi/pdfs/2005/MPMI-18-1027.pdf

   Farhad, F., Yang*, Y., Kumar*, D., Chen, Y., Fridman, E., Park, S.W.,  Chiang, Y., Acton, T.B., Montelione, G.T., Pichersky, E., Klessig D.F. and Tong, L. (2005) Structural and biochemical studies identify tobacco SABP2 as a methyl salicylate esterase and  implicate it in plant innate immunity. Proc. Natl. Acad. Sci. USA. 102: 1773-1778  *contributed equally to this work. http://www.pnas.org/cgi/reprint/102/5/1773.pdf

   Kumar, D. and Klessig, D.F. (2003) The high-affinity salicylic acid-binding protein 2 is required for plant innate immunity and has salicylic acid-stimulated lipase activity. Proc. Natl. Acad. Sci. USA. 100: 16101-16106.  http://www.pnas.org/cgi/reprint/100/26/16101.pdf

   SA- and NO-mediated signaling in Plant Disease Resistance (2002) In: Biology of Plant-Microbe Interactions. Ed. S.A. Leong, C. Allen, and E.W. Triplet, IS-MPMI, St Paul, MN. Vol. 3, pp 78-82. 

   Kumar, D. and Klessig, D.F. (2000) Differential induction of tobacco MAP kinases by the defense signals nitric oxide, salicylic acid, ethylene and jasmonic acid. Mol. Plant-Microbe Interact. 13: 347-351. http://www.apsnet.org/mpmi/pdfs/2000/0112-01N.pdf

   Klessig, D.F., Durner, J., Zhou, J.M., Kumar, D., Navarre, R., Zhang, S., Shah, J., Wendehenne, D., Du, H., Trifa, Y., Noad, R., Kachroo, P., Pontier, D., Lam, E. and Silva, H. (2000) NO and salicylic acid signaling in plant defense.  Proc. Natl. Acad. Sci. USA. 97: 8849-8855.  http://www.pnas.org/cgi/reprint/97/16/8849.pdf

   Salicylic acid- and nitric oxide-mediated signal transduction in plant disease resistance (2000) In: Biology of Plant-Microbe Interactions 2: 13-18. Edited by P. de Witt., T. Bisseling and W. Stiekema. Kluwer Academic Publishers, The Netherlands. 

   Salicylic acid- and nitric oxide-mediated signaling in plant-microorganism interactions (2000) In: 2000 Years of Natural Products Research; Past, Present and Future. Edited by T.J.C. Luijendijk, Phytoconsult, Leiden, The Netherlands, pp. 105-118.  

   Salicylic acid- and nitric oxide-mediated signal transduction in disease resistance (2000). In: Signal Transduction in Plants: Current Advances. Edited by S.K. Sopory, R. Oelmüller and S.C. Maheshwari. Kluwer Academic/ Plenum Publishers, The Netherlands. pp.  201-207.

   Gaikwad, A., Tewari, K.K., Kumar, D., Chen, W. and Mukherjee, S.K. (1999) Isolation and characterization of the cDNA encoding a glycosylated accessory protein of pea chloroplast DNA polymerase. Nuc. Acids Res. 27: 3120-3129.  http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=148538&blobtype=pdf

   Kumar, D., Verma, H.N., Tuteja, N. and Tewari, K.K. (1997) Cloning and characterization of a gene encoding an antiviral protein from Clerodendrum aculeatum L. Plant. Mol. Biol. 33: 745 751         http://www.springerlink.com/content/h6g550345567h7m3/fulltext.pdf

   Verma, H.N, Srivastava, S., Varsha and Kumar, D. (1996) Induction of systemic resistance in plants against viruses by a basic protein from Clerodendrum aculeatum  leaves. Phytopathology 86: 485-91 http://www.apsnet.org/phyto/PDFS/1996/Phyto86n05_485.pdf

   Chen, W., Gaikwad, A., Mukherjee, S.K., Choudhary, N.R., Kumar,  D., and Tewari, K.K. (1996) A 43 kDa DNA binding protein from the pea chloroplast interacts with and stimulates the cognate DNA polymerase. Nuc. Acids. Res. 24: 3953-3961 http://nar.oxfordjournals.org/cgi/reprint/24/20/3953

   Kumar, D., Mukherjee, S., Reddy, M.K. and Tewari, K.K. (1995) A novel single stranded DNA-specific endonuclease from pea chloroplasts. J. Exp. Bot. 46: 767-776 

   Reddy, M.K., Choudhary, N.R., Kumar, D., Mukherjee, S.K. and Tewari, K.K. (1994) Characterization and mode of in vitro replication of pea chloroplast OriA sequence. Eur. J. Biochem. 220: 933-941 http://www.blackwell-synergy.com/doi/pdf/10.1111/j.1432-1033.1994.tb18697.x

   Mukherjee, S.K., Reddy, M.K., Kumar, D. and Tewari, K.K. (1994) Purification and characterization of a eukaryotic type I topoisomerase from pea chloroplast. J. Biol. Chem. 269: 3793-3801 http://www.jbc.org/cgi/reprint/269/5/3793

   Ramachandran, P., Kumar, D., Varma, A., Pandey, P.K. and Singh, R.P. (1992) Coleus viroid in India. Current Science 62: 271-272 http://www.ias.ac.in/j_archive/currsci/62/2/271-272/viewpage.html

   Varma, A., Khetrapal, R.K., Vishwanath, S.M., Kumar, D., Maury, Y., Sharma, B. and Tyagi, M.C. (1991) Detection of Pea seed borne mosaic virus in commercial seeds of pea and germplasm of pea and lentil. Indian Phytopathology 44: 107-111

Patents 

      Klessig, D.F. and Kumar, D. Novel Salicylic Acid-Binding Protein Encoding Nucleic acid, SABP2, and Methods of Use Thereof. (2007) US Patent No. 7169966.

       Klessig, D.F. and Kumar, D. Methods of determining specificity of RNAi silencing. (2009) US Patent No. 7592504.

TEACHING

BIOL 5100             Topics: Cell and Molecular Biology

BIOL 4147/5147      Biochemistry of Macromolecules

BIOL 4157/5157      Biochemistry of Macromolecules-Lab

BIOL 4167/5167      Biochemistry of Metabolism

BIOL 4177/51         Biochemistry of Metabolism- Lab

BIOL 4300-008       Seminar in Biological Sciences

BIOL 1110             Biology for Science Majors-I

BIOL 1020             Biology for Non-Majors-II

Education

       Ph.D.    (1998)    International Center for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India 

     Positions Held

2005-present,    Assistant Professor of Biochemistry, Department of Biological Sciences, East Tennessee State University, Johnson City, TN 37614

2000-2005,        Research Associate, Boyce Thompson Institute for Plant Research, Ithaca, New York, 14853

1998-2000,        Post Doctoral Associate, Waksman Institute, Rutgers, The State  University of New Jersey, Piscataway, New Jersey, 08854    

Students in Research

Graduate Students (MS):

  Diwaker Tripathi is working in our research group since Fall of 2008. He comes to our lab from India. Diwaker Tripathi,  won the second place in “Natural Sciences & Mathematics” for Graduate Students (1-2 yrs) category  at the 2009 Appalachian Research Forum. In summer of 2009, he presented his research findings at the  49th Annual meeting for "Phytochemical Society of North America".

  Leonard Fai has come to our research group in the spring of 2009 from the University of Buea, Cameroon   

    Joannes Petrus Yuh: has come to our research group in the fall of 2009 from the University of Buea,Cameroon.

     Mir Hossain: has come to our research group in the fall of 2009 from the University of Dhaka, Bangladesh.

     LaTonya F. R. Gillespie: has come to our research group in the fall of 2009 from the Voorhees College, Denmark, South Carolina.

Undergraduate (BS):

  Tazley Hotz : Joined my lab as a freshman. Tazley has recently started working in the lab and is in the process of identifying a specific project. Tazley was awarded SURF (Summer  Undergraduate Research Fellowship) by American Society for Plant Biologists to conduct research in my lab during Summer of 2007. http://www.etsu.edu/etsu/news_text.asp?Action=ListEvent&EventID=6423 and http://www.etsu.edu/honors/international/newsarticle.asp?newsid=270. Recently Tazley was invited to present her research findings at the Plant Biology 2008 meeting held in Merida, Mexico. Abstract of her presentation could be seen at (http://abstracts.aspb.org/pb2008/public/P48/P48005.html). Tazley is a McNair Fellow.

     Arianna Ingram: A sophomore at ETSU. She is a biology major and wishes to pursue career in biological science research.

      Qian Sun: A senior at ETSU. She is pursuing her BS degree at ETSU as an exchange student from China.

      Yutika Patel: A chemistry major, has joined our lab in summer of 2008.

       Hira Chaudhary is an Honors student at ETSU.

Past Students:

Alexander Eddo: Has completed MS in Biology at ETSU and ready to join a Ph.D. program in molecular biology and biochemistry

Kajal Patel: Has graduated in spring of 2009 and joined a Pharmacy college.

Meng Liu: Has graduated and joined MS program in Public and Allied Health at ETSU.

Poonam M. Sheth: Poonam has graduated from ETSU and at present she is a project coordinator at Microbial insights, Rockville,           TN 37853 (http://www.microbe.com).

John W. Sayne: Establishment of Suspension Cell culture from tobacco leaves and general support to lab activities. John is expected to graduate shortly. He aspires to become a teacher.

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For students interested in MS in Biology, limited number of Graduate Assistantships for highly deserving candidates are available which covers their tuition fees and stipends. If you are interested in doing some cutting edge science feel free to contact me.

Undergraduate students could also avail the Federal Work Study and Research Discovery positions in my lab. Freshman at ETSU are especially encouraged contact me if interested in molecular biology and bichemistry research projects.

Contact me by telephone 423-439 6928 or email me at (kumard@etsu.edu).

Last updated: 10-01-2009