Research Groups

Plant Biology: Plant Transformation

Research Interests and Description

Staff Research Scientist: S. Leelavathi

Research Interests

Transgenic crops with improved agronomic traits, chloroplast genetic engineering, molecular farming, biofuel, fungal resistance, cotton genomics.

Description of Research

Cotton improvement
Cotton is one of the most important economic fiber crops grown the world over, worth several billions of dollars. We have developed efficient protocols to reduce the time involved in, and improve the frequency of, regeneration, and hastened transgenic plant development by directly transforming the embryogenic callus with the required genes. Some of the transgenic events with cry gene were found to be bioassay positive to confer resistance against Helicoverpa armigera and are being tested in the field, using Coker 310, a genotype not cultivated elsewhere. Recurrent backcrossing introgresses the foreign gene from Coker 310 into cultivated varieties.
We further developed an effective regeneration system for cotton parental lines used for hybrid seed production in India and for Narasimha, a parent in several hybrids. The transformation procedure has been extended with a view to introducing genes to confer insect resistance. We also pursue mining for useful genes from the cotton genome for fiber quality using proteomic and transcriptomic studies combined with functional genomics.
Molecular farming
Chloroplasts are organelles which can express large amounts (>6% of total soluble protein) of foreign proteins without adverse effects on plant growth and development. Monoclonal antibodies and pharmaceutically important molecules are expressed in tobacco chloroplasts, in collaboration with VTT, Finland, to explore the possibility of using plants as bioreactors
Biofuels
Twenty percent of the global enzyme market consists of cellulases, and increases annually by 6-7%. We work with plant cell wall degrading enzymes. Xylanase was taken as a model enzyme and was over expressed using chloroplast genetic engineering. We collaborate with the University of Pavia, Italy, to express different cell wall degrading enzymes in chloroplasts of tobacco with a view to utilize these in degrading carbohydrate polymers present in plant waste/biomass in the form of cell wall and convert them to simple carbohydrates that can be converted further into ethanol. One of the most important advantages of using chloroplasts in producing cell wall degrading enzymes is the large quantity that can be produced without harming the plant cell where it is produced. Additionally, the present huge need for biofuels can only be met by this technology providing the cost-effective enzymes in large quantities, which can be produced and processed easily and quickly with little effort. Presently, important cellulolytic enzymes used for digestion of cell walls, cellulases, pectinases and Xylanase are readily expressing in tobacco in the laboratory, while work is underway to express more of these including lignases. We are proceeding to develop optimal conditions for degradation, and degradation of different biomasses obtained mostly from water, hyacinth, or from different grasses into sugars, like glucose and xylan, and further degrading these through fermentation into different byproducts including ethanol.

Recent Publications

Bharadwaj, A., Leelavathi1, S., Mazumdar-Leighton, S., Ghosh, A., Ramakumar, S., Reddy, V.S. 2008. The Critical Role of Partially Exposed N-Terminal Valine Residue in Stabilizing GH10 Xylanase from Bacillus sp.NG-27 under Poly-Extreme Conditions. PLOS One, 3, e3063

Leelavathi, S., Sunnichan, V.G., Kumria, R., Vijaykanth, G.P., Bhatnagar, R.K., Reddy, V.S. 2004. A simple and rapid Agrobacterium-mediated transformation protocol for cotton (Gossypium hirsutum L.): Embryogenic calli as a source to generate large numbers of transgenic plants. Plant Cell Rep. 22, 465-470

Nguyen, H.T., Leelavathi, S., Reddy, V.S. 2004. Bacteriophage T7 RNA polymerase directed inducible and tissue specific overexpression of foreign genes in transgenic plants. Plant Biotechnol. J. 2, 301-310

Leelavathi, S., Reddy, V.S. 2003. Chloroplast expression of His-tagged GUS-fusions: A general strategy to overproduce and purify foreign proteins using transplastomic plants as bioreactors. Mol. Breed. 11, 49-58

Kumria, R., Leelavathi, S., Bhatnagar, R.K., Reddy, V.S. 2003. Regeneration and Genetic Transformation of cotton: Present status and future perspectives. Plant Tissue Cult. 13, 211-225