Ajith Anand's Research Interests

The advent of ‘omics’ technologies in plant biology over the last few years has created a platform providing opportunities to functionally characterize genes, both known and unknown in diverse cellular responses. One of the best studied plant response is its interaction to pathogens, and interestingly Agrobacterium-mediated plant transformation is a unique example of such an interaction that allows studying multitudes of diverse cellular interactions under one roof. Agrobacterium is a soil borne pathogen that elicits neoplastic growth at wounded sites on most dicots, causing the crown gall disease. During the process of infection, the phytopathogen successfully transfers a small component of its DNA residing on the tumor-inducing (Ti) plasmid that integrates into the plant genome producing the tumors. Modern plant breeding greatly relies on this tool for transferring foreign genes from one plant to another plant. Research on the role of plant genes in this interaction is poorly characterized when compared to the knowledge we have in Agrobacterium biology. It is therefore speculated that better characterization of plant genes in this interaction including the signal transduction pathways will facilitate in developing appropriate disease-control methods, improving the transformation efficiencies of crop plants and creating better transgenics for future.

Plant factors required for Agrobacterium-mediated transformation
My main project is to use a functional genomics approach based on virus-induced gene silencing (VIGS) to transiently knockdown both known and unknown plant genes involved in Agrobacterium-mediated plant transformation by fast-forward and reverse genetics studies. The gene silenced plants are characterized for their functional roles by using in planta and in vitro transformation assays developed in the laboratory. Some of my significant contributions in this area of research include the functional characterization of the host protein VIP2, a VirE2-interactor protein 2 that is required for T-DNA integration. The full-length cDNA corresponding to gene from Nicotiana benthamiana has been cloned and studies are underway using VIGS, RNAi and overexpression analyses to further characterize the biological role of this gene.

It is hypothesized that the targeted proteolysis of the T-complex is prerequisite for successful integration of the T-DNA into the plant genome. In another project I am horning my skills to address this issue by transiently knocking down many genes including SGT1, RAR1, Skp1, and Cul1c in the E3-ubiquitin ligase pathway. These silenced plants upon infection with wild-type Agrobacterium produced smaller tumors when compared to the wild-type. Experiments are under way to determine which step of transformation is blocked in these silenced plants.

I am also involved in a large scale screening using a fast-forward genetics approach and have identified many plant genes that are potentially involved in Agrobacterium-mediated transformation. Efforts are underway to further characterize these genes. I am also employing VIGS-based approaches to characterize the role of plant defense genes during Agrobacterium infection. A finding related to this is the role of salicylic acid (SA) in attenuating the crown gall disease, which has high economic importance. This finding is in accordance to the earlier findings that many defense genes are repressed upon infection with T-DNA transfer competent Agrobacterium strains.

Selected Publications

Anand, A., Krichevsky, A., Schornack, S., Lahaye, T., Tang, Y., Tzfira, T., Citovsky, V and Mysore, K.S. 2007. VIP2, a VIE2- plant-interactor protein is required for T-DNA integration and stable transformation by Agrobacterium. Plant Cell (accepted)

Anand, A., Vaghchhipawala, Z., Ryu, C. M., Kang, L., del-Pozo, O, Martin G. B., and Mysore, K. S. 2007. Identification of plant genes involved in Agrobacterium-mediated transformation by using virus-induced gene silencing as a functional genomics tool. Molecular Plant-Microbe Interaction 20: 42-51

Wang, K., Kang, L., Anand, A., Lazarovits, G., and Mysore, K. S. (2007). Monitoring in planta bacterial infection at both cellular and whole-plant levels using the green fluorescent protein variant GFPuv. New Phytologist 174: 121-223 (cover page article)

Lei, Z., Anand, A., Mysore, K. S. and Sumner L. W. 2006. Electroelution of intact proteins from SDS-PAGE gels and their subsequent MALDI-TOF MS analysis Methods Molecular Biology 355: 353-364

Ryu, C.M., Anand, A., Kang, L. and Mysore, K. 2004. Agrodrench: a novel and effective agroinoculation method for virus induced gene silencing in roots and diverse Solanaceous species. Plant Journal 40: 322-331

Anand, A., Lei, Z., Sumner, L., Arakane, Y., Mysore, K., Bockus, B. and Muthukrishnan, S. 2004. The apoplastic extracts from a transgenic wheat line exhibiting lesion-mimic phenotype have multiple pathogenesis-related proteins that are antifungal. Molecular Plant-Microbe Interactions 17: 1306-1317

Anand, A., Schmelz, E. A. and Muthukrishnan, S. 2003. Development of a lesion-mimic phenotype in a transgenic wheat line over-expressing genes for pathogenesis-related (PR-) proteins is dependent on salicylic acid concentration. Molecular Plant-Microbe Interactions 16: 916-925

Anand, A., Trick, H.N., Gill, B.S. and Muthukrishnan, S. 2003. Stable transgene expression and random gene silencing in wheat. Plant Biotechnology Journal 1: 241-252

Anand, A., Zhou, T., Bockus, B., Muthukrishnan, S., Trick, H.N. and Gill, B.S. 2003. Greenhouse and field testing of transgenic wheat plants stably expressing genes for thaumatin-like protein, chitinase and glucanase against Fusarium graminearum. Journal of Experimental Botany 54: 1-1