: Plants inherently show resistance to pathogen attack but are susceptible to multiple bacteria, viruses, fungi, and phytoplasmas. Diseases as a result of such infection result in the deterioration of crop yield. Several pathogen-sensitive gene activities, promoters of such genes, associated transcription factors, and promoter elements responsible for crosstalk be- tween the defense signaling pathways are involved in plant resistance towards a pathogen. Still, only a handful of genes and their promoters related to plant resistance have been identified to date. Such pathogen-sensitive promoters are accountable for elevating the transcriptional activity of certain genes in response to infection. Also, a suitable promoter is a key to devis- ing successful crop improvement strategies as it ensures the optimum expression of the required transgene. The study of the promoters also helps in mining more details about the transcription factors controlling their activities and helps to unveil the involvement of new genes in the pathogen response. Therefore, the only way out to formulate new solutions is by analyzing the molecular aspects of these promoters in detail. In this review, we provided an overview of the promoter motifs and cis- regulatory elements having specific roles in pathogen attack response. To elaborate on the importance and get an adequate picture of the pathogen-sensitive promoter sequences, the key motifs and promoter elements were analyzed by PlantCare and interpreted with available literature. This systematic review intends to provide useful information for reconstructing the gene networks underlying the resistance of plants against pathogens.

Several isolates of Banana bunchy top virus (BBTV) have been reported worldwide. They are members of either the Pacific Indian Ocean (PIO) or the South East Asian (SEA) group. However, there is only one completely sequenced isolate published from the northeastern part of India till date. Therefore, we obtained the complete sequences of all the six genomic components of a BBTV isolate from the northeastern Indian state of Assam. The isolate was named as BBTV-As-JOR, and its genome showed the presence of the reported conserved motifs. Nevertheless, like other Indian BBTV isolate, the major common regions in DNA-R and DNA-U3 of BBTV-As-JOR had deletions of 26 and 36 nucleotides, respectively. Phylogenetic analysis based on 312 sequences of BBTV DNA-R classified BBTV-As-JOR as a member of the PIO group; similar phylogenetic patterns were also found with the other genomic segments. Analysis with Recombination Detection Program revealed two intra-segment recombination events involving DNA-C of geographically distinct BBTV isolates. On the other hand, DNA-U3 and DNA-N were found to be involved in few inter-segment recombination events in BBTV-As-JOR. This is the first report of a BBTV isolate from Assam and also of another PIO isolate from the region (the other isolate, BBTV-Umiam, was much closer to the SEA group). The detected possible recombinants could emerge as a major future threat for the banana cultivations in the country considering the asexual nature of propagation of banana crop.

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Potato affecting viruses is an important biotic factor that hampers both the quality and yield of potato production worldwide. The occurrence of potato viruses has been historically recorded in India. Viruses such as potato virus X (PVX), potato virus Y (PVY), potato virus A (PVA), potato virus M (PVM), potato virus S (PVS), potato leafroll virus (PLRV) have been recorded in all potato growing zones. To investigate the presence and distribution of potato virus diseases in North‐East India, a survey of seven major potato growing regions was conducted during the 2017 and 2018 growing seasons. The presence of potato viruses was confirmed by double antibody sandwich ELISA (DAS‐ELISA) with reverse transcriptase polymerase chain reaction (RT‐PCR) performed on selected samples. The sequencing followed by annotation of PCR amplicons obtained from RT‐PCR showed 95–100% nucleotide sequence identities with respective virus accessions on NCBI GenBank. The multiple sequence analysis and phylogenetic studies provided an overview of the genetic diversity pattern among different potato virus isolates. This study reveals a broad picture of the potato virus infections occurring in Northeastern states of India, which may be useful to develop effective control strategies against the potato viruses.

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The pumpkin leaf curl disease is an emerging disease of pumpkin in Assam, India. Symptomatic pumpkin leaf samples from different locations were immunologically tested using Begomovirus specific antibody. PCR with the ELISA-positive samples, using Geminivirus universal primers amplified 1.4 kb virus-specific fragments. Sequence of these amplicons showed around 95% identity with squash leaf curl China virus-[Pumpkin: Varanasi] (SLCCV-Pumpkin: Varanasi EU573715). To investigate the possible functions of the viral proteins present in the fragment, the full-length C2 and C3 genes were conceptually translated and were subjected to in silico proteomic analyses. The phylogenetic analysis of both the proteins divulged the relationship of our isolate with related viruses and isolates. Multiple sequence alignment (MSA) of the proteins revealed the presence of the known viral conserved motifs, viz., zinc-finger (ZNF) motif [ 36 CXCX(7)CX(6)H 53 ], the arginine-rich nuclear localization signal (NLS) motif ( 28 RRRR 31 ) as well as the minimal activation domain in C2 protein. In the C3 protein, the 91 LKYLD 95 and the replication enhancer motif ( 30 YFK 32 ) were found to be conserved. Finally, 3-D models of the two proteins were predicted via ab initio approach and subsequently, the models were validated. To our knowledge, this study is a pioneering attempt to construct the ab initio 3-D models of two begomoviral proteins taking a SLCCV isolate as a model.

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