Subbaratnam Muthukrishnan, Ph.D.
University Distinguished Professor Emeritus

Image of Subbaratnam Muthukrishnan, Ph.D.

Contact information



B.S. 1963, Madras University
M.S. 1965, Madras University
Ph.D. 1970, Indian Institute of Science

Areas of specialty

  • Characterization of enzymes and genes involved in chitin metabolism and targeting them for insect control
  • Enhancing disease and insect resistance of plants by genetic engineering

The main focus of our laboratory is the identification of all genes involved in the biosynthesis, organization and degradation of chitin in insects. We have identified more than 60 genes of chitin metabolism in the genome of the red flour beetle, Tribolium castaneum by bioinformatics search of the insect's genme. We are currently utilizing RNA interference to elucidate the function of each of these genes in collaboration with Drs. Karl Kramer, Richard Beeman and Yasuyuki Arakane (Chonnam University), Bernard Moussian (University of Tubingen) and Hans Merzendorfer (University of Osnabrueck). We are also studying the role of laccases and other phenoloxidases in cuticle tanning in collaboration with Dr. Michael Kanost and Dr. Karl J. Kramer. We are also studying the role of neuropeptide hormones in insect development in collaboration with Dr. Yoonseong Park of the Entomology Department, KSU.

Our other interests include: Identification and characterization of genes involved in plant defense against microbial pathogens; Plant transformation protocols for introduction of defense genes into crop plants; and bioassays of transgenic crop plants (wheat, sorghum, corn, soybean) for resistance to fungi and insect pests.

Selected publications

Agrawal, S., Kelkenberg, M., Begum, K., Lea, S., Williams, CE., Kramer, KJ., Park, Y., Muthukrishnan, S., and Merzendorfer, M. (2014) Two essential peritrophic matrix proteins mediate matrix barrier functions in the insect midgut. Insect Biochemistry and Molecular Biology, 49:24-34

Chaudhari, SS., Arakane, Y., Specht, CA., Moussian, B., Kramer, KK., Muthukrishnan, S., and Beeman, RW. (2013) Retroactive maintains cuticle integrity by promoting the trafficking of Knickkopf into the procuticle of Tribolium castaneum. PLoS Genetics PGENETICS-D-12-02532R1 10.1371/journal.pgen.1003268

Jasrapuria S, Specht CA, Kramer KJ, Beeman RW, Muthukrishnan S (2012) Gene Families of Cuticular Proteins Analogous to Peritrophins (CPAPs) in Tribolium castaneum Have Diverse Functions. PLoS ONE, 7(11): e49844. doi:10.1371/journal.pone.0049844

Muthukrishnan, S., Merzendorfer, H., Arakane, Y., and Kramer, KJ. (2012) Chitin metabolism in insects. In: Insect Biochemistry and Molecular Biology. Ed. By. Gilbert, L. I. Elsevier Inc., San Diego, ISBN:-978-0-12-384747-8. pp.193-235.

Chaudhari, SS., Arakane, Y., Specht, CA., Moussian, B., Boyle, DL., Park, Y., Kramer, KJ., Beeman, RW., and Muthukrishnan, S. (2011) The Knickkopf protein protects and organizes chitin in the newly synthesized insect exoskeleton. Proc Natl Acad Sci USA., 108:17028-17033.

Arakane, Y., and Muthukrishnan, S. (2010) Insect chitinases and chitinase-like proteins. Cellular Molecular Life Sciences, 67, 201-216.

Jasrapuria, S., Arakane, Y., Osman, G., Kramer, KJ., Beeman, RW., and Muthukrishnan, S. (2010) Genes encoding proteins with peritrophin A-type chitin binding domains in Tribolium castaneum are grouped into three distinct families based on phylogeny, expression and function. Insect Biochem Mol. Biol., 40: 214-227.

Arakane, Y., Begum, K., Dixit, R., Park, Y., Specht, CA., Kramer, KJ., and Beeman, RW. (2009) Analysis of functions of the chitin deacetylase gene family in Tribolium castaneum. Insect Biochem Molec Biol., 38: 959-962.

Zhu Q, Arakane Y, Beeman RW, Kramer KJ, and Muthukrishnan S. (2008) Functional specialization among insect chitinase family genes revealed by RNA interference. Proc Natl Acad Sci USA., 105:6650-6655.

Arakane, Y., Muthukrishnan, S., Kramer, KJ., Specht, CA., Tomoyasu, Y., Lorenzen, MD., Kanost, M., and Beeman, RW. (2005) The Tribolium chitin synthase genes TcCHS1 and TcCHS2 are specialized for synthesis of epidermal cuticle and midgut peritrophic matrix. Insect Molec. Biol., 14:453-463.

Arakane, Y., Muthukrishnan, S., Beeman, RW., Kanost, MR., and Kramer, KJ. (2005) Laccase 2 is the phenoloxidase gene required for beetle cuticle tanning. Proc. Natl. Acad. Sci. USA., 102:11337-11342.

Hogenkamp, DG., Arakane, Y., Zimoch, L., Merzendorfer, H., Kramer, KJ., Beeman, RW., Kanost, MR., Specht, CA., and Muthukrishnan, S. (2005) Chitin synthase genes in Manduca sexta: characterization of a gut-specific transcript and differential tissue expression of alternatively spliced mRNAs during development. Insect Biochem. Molec. Biol., 35:529-540.

Arakane, Y., Hogenkamp, DG., Zhu, Y-C., Kramer, KJ., Specht, CA., Beeman, RW., Kanost, MR., and Muthukrishnan, S. (2004) Characterization of two chitin synthase genes of the red flour beetle, Tribolium castaneum, and alternate exon usage in one of the genes during development. Insect Biochem Molec. Biol., 34: 291-304

Complete Publications List