Research Groups

Plant Biology: Plant Molecular Biology

Research Interests and Description

Research Interests

Abiotic and Biotic stress, gene expression, signalling, crop improvement, transgenics, viral replication and RNAi, microRNA.

Description of Research

The Group is involved in understanding and improving plant adaptation towards abiotic stresses and developing strategies for obtaining virus resistant plants by unraveling the mechanism of DNA replication following viral invasion.
Abiotic Stress regulated genes
About 2000 differentially expressed ESTs have been obtained from pokkali, a sensitive and a saline tolerant rice cultivar. Transcript analysis has been done for 10 HSPs and 26 members of a CBS domain family genes. One of the CBS domain containing proteins has been functionally validated in tobacco and found to confer improved tolerance to different  stresses. A cold stress regulated bi-polar DNA helicase (PDH47) and translational initiation factor 4A (eIF4A/PDH45) from pea and Pennisetum have been characterized. Three mini chromosome maintenance proteins have been cloned and the encoded recombinant proteins purified. The first direct evidence that links the G-proteins to high salinity and heat stress tolerance has been shown.
Stress signal transduction
We investigated the role of PLC/PLD, calcineurin B-like (CBL) proteins and G-proteins and calmodulin binding protein CAMTA in stress signaling and have identified their interacting partners. Gα1 and Gα2 subunits were shown to interact with pea PLC protein.
Stress regulated promoters and transcription factors
The lab has cloned a number of stress inducible promoters from pea, rice and brassica. Reporter assays have revealed that some promoters respond to multiple stresses. A stress down regulated promoter has also been cloned and analysed .The  downregulation was found to be due to stress mediated removal of transcription factors and histone modifications. SOS2 promoter from Brassica has been cloned showing multiple stress induction in transgenic Brassica.
Developing stress tolerant transgenic plants
An antibiotic marker free system for the selection of transgenics has been developed based on the glyoxalase system. The Group has engineered rice overexpressing glyoxalase I and II, vacuolar antiporter and PDH45 genes and works on pyramiding genes, making mega vectors for gene encoding ROS pathway enzymes and Glyoxalase I and II and NHX together. Some events have been transferred to seed companies for validation and back-crossing program.
Biotic stress tolerance
A random 12-mer-peptide library was screened for peptides interacting with the MYMIV-Rep protein using phage-display methodology. About 33 peptides positive for interaction, were among the 130 proteins from plants or yeast reported in the database, 25 are identified to act as replication factors. One of these, RAD54 interacted with MYMIV-Rep both in yeast-two hybrid and in-vitro pull-down assays, The biochemical role of RAD54 is being explored. Using assays based on reversal of GFP-silencing, the RNAi-suppressors from 3 plants and 1 animal virus have been isolated. Host proteins that interact with the MYMIV-AC2 suppressor and the important roles of host PCNA and RP-A proteins in the rolling circle replication of MYMIV DNA, are being elucidated with the help of a MYMIV-based VIGS vector developed in the lab. Using a technique developed here, 40 novel microRNAs from rice-leaves have been isolated and validated. Work in compararive profiling of the entire miRNA population using high throughput techniques (pyro- sequencing, miRNA – arrays) has been initiated. Studies on gall midge insect and plant have been initiated and  the genes encoding proteins excreted by the insect are been identified.

Recent Publications

Sanan-Mishra, N., Kumar, V., Sopory, S.K., Mukherjee, S.K. 2009. Cloning and Validation of novel miRNA from basmati rice indicates cross-talk between abiotic and biotic stresses. Mol. Gen. Genomics [Epub ahead of print]

Singh, G., Popli, S., Yukti, H., Palhotra, P., Mukherjee, S.K., Bhatnagar, R.K. 2009. Suppression of RNA silencing by Flock house virus B2 protein is mediated through  its  interaction with  the PAZ  domain of the Dicer. FASEB J. In press

Joshi, A., Dang, H.Q., Vaid, N., Tuteja, N. 2009. Isolation of high salinity stress tolerant genes from Pisum sativum by random overexpression in Escherichia coli and their functional validation. Plant Signaling Behaviour 4, 400-412

Kumari, S., Sabharwal-Panjabi, V., Khushwa, H.R., Sopory, S.K., Singla-Pareek, S.L., Pareek, A.P. 2009. Transcriptome map for seedling stage specific salinity stress response indicates a specific set of genes as candidates for saline tolerance in oryza sativa L. Funct. Integ. Genomics 9, 109-123

Kushwaha, H.R., Singh, A.K., Sopory, S.K., Singla-Pareek, S.L., Pareek, A. 2009. Genome wide expression analysis of CBS domain containing proteins in Arabidopsis thaliana (L.) Heynh and Oryza sativa L. reveals their developmental and stress regulation.BMC Genomics. 28, 200

Reddy, R.A., Kumar, B., Reddy, P.S., Mishra, R.N., Mahanty, S., Kaul, T., Nair, S., Sopory, S.K., Reddy, M.K. 2009. Molecular cloning and characterization of genes encoding Pennisetum glaucum ascorbate peroxidase and heat-shock factor: Interlinking oxidative and heat-stress responses. J Plant Physiol. 166, 1646-1659