Browsing by Author "Chakraborty, Supriya"

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Chilli leaf curl virus infection highlights the differential expression of genes involved in protein homeostasis and defense in resistant chilli plants
(Springer, 2015) Kushwaha, Nirbhay; Sahu, Pranav Pankaj; Prasad, Manoj; Chakraborty, Supriya
Geminiviruses have evolved with tremendous potential of recombination and possess the ability to manipulate several cellular processes of hosts. Chilli leaf curl virus (ChiLCV) is a monopartite Begomovirus (family Geminiviridae) which has emerged as a serious threat to chilli production worldwide. To date, development of resistant chilli varieties through conventional plant breeding techniques remains the major antiviral strategy. To explore the potential resistance factors in Capsicum annuum var. Punjab Lal, we performed a transcriptome analysis in ChiLCV-infected plants by exploiting the advantage of sensitivity and efficiency of suppression subtractive hybridization (SSH). Out of 480 clones screened, 231 unique expressed sequence tags (ESTs) involved in different cellular and physiological processes were identified. An interactome network of ChiLCV responsive differentially expressed genes revealed an array of proteins involved in key cellular processes including transcription, replication, photosynthesis, and defense. A comparative study of gene expression between resistant and susceptible chilli plants revealed upregulation of several defense-related genes such as nucleotide-binding site leucine-rich repeat (NBS-LRR) domain containing protein, lipid transfer protein, thionin, polyphenol oxidase, and other proteins like ATP/ADP transporter in the ChiLCV-resistant variety. Taken together, the present study provides novel insights into the transcriptomics of ChiLCV-resistant chilli plants.
The Sw5a gene confers resistance to ToLCNDV and triggers an HR response after direct AC4 effector recognition
(PNAS, USA, 2021) Sharma, Namisha; Sahu, Pranav Pankaj; Prasad, Ashish; Muthamilarasan, Mehanathan; Waseem, Mohd; Khan, Yusuf; Thakur, Jitendra K.; Chakraborty, Supriya; Prasad, Manoj
Several attempts have been made to identify antiviral genes against Tomato leaf curl New Delhi virus (ToLCNDV) and related viruses. This has led to the recognition of Ty genes (Ty1-Ty6), which have been successful in developing virus-resistant crops to some extent. Owing to the regular appearance of resistance-breaking strains of these viruses, it is important to identify genes related to resistance. In the present study, we identified a ToLCNDV resistance (R) gene, SlSw5a, in a ToLCNDV-resistant tomato cultivar, H-88-78-1, which lacks the known Ty genes. The expression of SlSw5a is controlled by the transcription factor SlMyb33, which in turn is regulated by microRNA159 (sly-miR159). Virus-induced gene silencing of either SlSw5a or SlMyb33 severely increases the disease symptoms and viral titer in leaves of resistant cultivar. Moreover, in SlMyb33-silenced plants, the relative messenger RNA level of SlSw5a was reduced, suggesting SlSw5a is downstream of the sly-miR159-SlMyb33 module. We also demonstrate that SlSw5a interacts physically with ToLCNDV-AC4 (viral suppressor of RNA silencing) to trigger a hypersensitive response (HR) and generate reactive oxygen species at infection sites to limit the spread of the virus. The "RTSK" motif in the AC4 C terminus is important for the interaction, and its mutation completely abolishes the interaction with Sw5a and HR elicitation. Overall, our research reports an R gene against ToLCNDV and establishes a connection between the upstream miR159-Myb33 module and its downstream target Sw5a to activate HR in the tomato, resulting in geminivirus resistance.
Tomato 26S Proteasome subunit RPT4a regulates ToLCNDV transcription and activates hypersensitive response in tomato
(Nature Publishing Group, 2016) Sahu, Pranav Pankaj; Sharma, Namisha; Puranik, Swati; Chakraborty, Supriya; Prasad, Manoj
Involvement of 26S proteasomal subunits in plant pathogen-interactions, and the roles of each subunit in independently modulating the activity of many intra- and inter-cellular regulators controlling physiological and defense responses of a plant were well reported. In this regard, we aimed to functionally characterize a Solanum lycopersicum 26S proteasomal subunit RPT4a (SlRPT4) gene, which was differentially expressed after Tomato leaf curl New Delhi virus (ToLCNDV) infection in tolerant cultivar H-88-78-1. Molecular analysis revealed that SlRPT4 protein has an active ATPase activity. SlRPT4 could specifically bind to the stem-loop structure of intergenic region (IR), present in both DNA-A and DNA-B molecule of the bipartite viral genome. Lack of secondary structure in replication-associated gene fragment prevented formation of DNA-protein complex suggesting that binding of SlRPT4 with DNA is secondary structure specific. Interestingly, binding of SlRPT4 to IR inhibited the function of RNA Pol-II and subsequently reduced the bi-directional transcription of ToLCNDV genome. Virus-induced gene silencing of SlRPT4 gene incited conversion of tolerant attributes of cultivar H-88-78-1 into susceptibility. Furthermore, transient overexpression of SlRPT4 resulted in activation of programmed cell death and antioxidant enzymes system. Overall, present study highlights non-proteolytic function of SlRPT4 and their participation in defense pathway against virus infection in tomato.
Tomato cultivar tolerant to tomato leaf curl New Delhi Virus infection induces virus-specific siRNA accumulation and defense associated host gene expression
(Wiley-Blackwell, 2010) Sahu, Pranav Pankaj; Rai, Neeraj K.; Chakraborty, Supriya; Singh, Major; Chandrappa, Prasanna H.; Ramesh, Bandarupalli; Chattopadhyay, Debasis; Prasad, Manoj
Tomato leaf curl New Delhi virus (ToLCNDV) infection causes significant yield loss in tomato. The availability of a conventional tolerance source against this virus is limited in tomato. To understand the molecular mechanism of virus tolerance in tomato, the abundance of viral genomic replicative intermediate molecules and virus-directed short interfering RNAs (siRNAs) by the host plant in a naturally tolerant cultivar H-88-78-1 and a susceptible cultivar Punjab Chhuhara at different time points after agroinfection was studied. We report that less abundance of viral replicative intermediate in the tolerant cultivar may have a correlation with a relatively higher accumulation of virus-specific siRNAs. To study defence-related host gene expression in response to ToLCNDV infection, the suppression subtractive hybridization technique was used. A library was prepared from tolerant cultivar H-88-78-1 between ToLCNDV-inoculated and Agrobacterium mock-inoculated plants of this cultivar at 21 days post-inoculation (dpi). A total of 106 nonredundant transcripts was identified and classified into 12 different categories according to their putative functions. By reverse Northern analysis and quantitative real-time polymerase chain reaction (qRT-PCR), we identified the differential expression pattern of 106 transcripts, 34 of which were up-regulated (>2.5-fold induction). Of these, eight transcripts showed more than four fold induction. qRT-PCR analysis was carried out to obtain comparative expression profiling of these eight transcripts between Punjab Chhuhara and H-88-78-1 on ToLCNDV infection. The expression patterns of these transcripts showed a significant increase in differential expression in the tolerant cultivar, mostly at 14 and 21 dpi, in comparison with that in the susceptible cultivar, as analysed by qRT-PCR. The probable direct and indirect relationship of siRNA accumulation and up-regulated transcripts with the ToLCNDV tolerance mechanism is discussed.