Gajendra Mohan Baldodiya

Bio: Gajendra Mohan Baldodiya is an academic researcher from Assam Agricultural University. The author has contributed to research in topics: Promoter & Plant virus. The author has an hindex of 2, co-authored 6 publications receiving 11 citations. Previous affiliations of Gajendra Mohan Baldodiya include Academy of Scientific and Innovative Research.

Dissecting the Role of Promoters of Pathogen-sensitive Genes in Plant Defense

Abstract: Plants inherently show resistance to pathogen attack but are susceptible to multiple bacteria, viruses, fungi, and phytoplasmas. Diseases as a result of such infection leads to the deterioration of crop yield. Several pathogen-sensitive gene activities, promoters of such genes, associated transcription factors, and promoter elements responsible for crosstalk between 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 devising 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 a vivid picture of the pathogen-sensitive promoter sequences, the key motifs and promoter elements were analyzed with the help of PlantCare and interpreted with available literature. This review intends to provide useful information for reconstructing the gene networks underlying the resistance of plants against pathogens.

Molecular characterization and sequence analyses of Banana bunchy top virus infecting banana cultivar Jahaji (Dwarf Cavendish) in Assam, India.

Abstract: 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.

Targeting Metabolic Pathways for Abiotic Stress Tolerance Through Genetic Engineering in Rice

Abstract: Rice is one of the leading staple foods and widely consumed worldwide. The production of rice is mostly affected by major abiotic stresses like drought, salinity, cold and high temperature by disturbing the metabolic processes involved in its growth and development. Engineering those sensitive metabolic pathways by targeting the metabolites involved could make the plant tolerant to these abiotic stresses. Therefore, targeting metabolic pathways through genetic engineering in rice is one of the major strategies for crop improvement. Metabolic engineering is a powerful tool for optimizing a targeted metabolite regulatory process to increase the cellular production of the specific metabolite. Engineered metabolic pathways can be achieved by modification in a single stress-responsive gene or multiple associated genes. Therefore, primary step to metabolite engineering is the identification of target genes involved in abiotic stress-responsive metabolic pathways. Metabolic pathways such as osmolyte pathways, reactive oxygen species pathways, hormonal pathways and other signal transduction pathways are the potential targets of genetic engineering for abiotic stress tolerance in rice. On the other hand, emerging techniques such as CRISPR Cas9/Cpf1 targeting negative regulatory metabolic pathway genes add more possibility to develop sustainable abiotic stress tolerance in rice. Overall, this chapter summarizes the earlier major findings to the most recent discoveries in the field of metabolic engineering by targeting important pathways involved in abiotic stress tolerance in rice. The novel genetic engineering tools and proposed potential targets of metabolic engineering for abiotic stress tolerance would have huge impact on sustainable productivity and rice crop improvement.

Host-Parasite Interaction During Development of Major Seed-Transmitted Viral Diseases

Abstract: Being the most important mode of propagation of plants, disease-free seed is a basic requirement of progressive agriculture. However, many plant pathogens such as bacteria, fungi, virus, virus-like agents, nematodes, etc. are transmitted through seeds to the next generation. Seed transmission enables the earliest possible infection, which is a determining factor of disease severity. Plant viruses are the most important plant pathogens causing up to 96% yield losses. Although, seed transmissibility is presently known to occur for around 18% of plant viruses only, it is estimated that one-third of the plant viruses will eventually prove to be seed transmitted in at least one host. Nevertheless, the most likely mechanism of plant viruses’ persistence between crop seasons is through the seeds, and even a seed transmission rate as low as 0.001 has the potential to initiate an epidemic. Therefore, study of the plant-pathogen interactions in seed-transmitted viruses is of utmost importance to help formulate preventive measures against such pathogens. Although the specific molecular mechanism of transmission of plant viruses through seeds is not completely understood till date, broadly, the mode of infection of the embryos (the future seeds) is known to be either direct (via mother plant) or indirect (via infected pollen); these mechanisms, however, may not be mutually exclusive. The modes of viral movement from infected maternal and paternal tissues to the embryo, the genetics of host-virus interaction, etc. are needed to be worked out for designing successful management strategies against seed-transmitted viruses.

Banana Diseases Including Plantains and Abaca

Abstract: Banana diseases; including plantains and abaca , Banana diseases; including plantains and abaca , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Elucidating the Response of Crop Plants towards Individual, Combined and Sequentially Occurring Abiotic Stresses

Abstract: In nature, plants are exposed to an ever-changing environment with increasing frequencies of multiple abiotic stresses. These abiotic stresses act either in combination or sequentially, thereby driving vegetation dynamics and limiting plant growth and productivity worldwide. Plants' responses against these combined and sequential stresses clearly differ from that triggered by an individual stress. Until now, experimental studies were mainly focused on plant responses to individual stress, but have overlooked the complex stress response generated in plants against combined or sequential abiotic stresses, as well as their interaction with each other. However, recent studies have demonstrated that the combined and sequential abiotic stresses overlap with respect to the central nodes of their interacting signaling pathways, and their impact cannot be modelled by swimming in an individual extreme event. Taken together, deciphering the regulatory networks operative between various abiotic stresses in agronomically important crops will contribute towards designing strategies for the development of plants with tolerance to multiple stress combinations. This review provides a brief overview of the recent developments in the interactive effects of combined and sequentially occurring stresses on crop plants. We believe that this study may improve our understanding of the molecular and physiological mechanisms in untangling the combined stress tolerance in plants, and may also provide a promising venue for agronomists, physiologists, as well as molecular biologists.

Heritable targeted mutagenesis in maize using a designed endonuclease. Plant J

Abstract: The liguleless locus (liguleless1) was chosen for demonstration of targeted mutagenesis in maize using an engineered endonuclease derived from the I-CreI homing endonuclease. A single-chain endonuclease, comprising a pair of I-CreI monomers fused into a single polypeptide, was designed to recognize a target sequence adjacent to the LIGULELESS1 (LG1) gene promoter. The endonuclease gene was delivered to maize cells by Agrobacterium-mediated transformation of immature embryos, and transgenic T(0) plants were screened for mutations introduced at the liguleless1 locus. We found mutations at the target locus in 3% of the T(0) plants, each of which was regenerated from independently selected callus. Plants that were monoallelic, biallelic and chimeric for mutations at the liguleless1 locus were found. Relatively short deletions (shortest 2 bp, longest 220 bp) were most frequently identified at the expected cut site, although short insertions were also detected at this site. We show that rational re-design of an endonuclease can produce a functional enzyme capable of introducing double-strand breaks at selected chromosomal loci. In combination with DNA repair mechanisms, the system produces targeted mutations with sufficient frequency that dedicated selection for such mutations is not required. Re-designed homing endonucleases are a useful molecular tool for introducing targeted mutations in a living organism, specifically a maize plant.

The CRISPR/Cas System can be used as Nuclease for in planta Gene Targeting and as Paired Nickases for Directed Mutagenesis in Arabidopsis Resulting in Heritable Progeny

Abstract: The CRISPR/Cas nuclease is becoming a major tool for targeted mutagenesis in eukaryotes by inducing double-strand breaks (DSBs) at pre-selected genomic sites that are repaired by non-homologous end joining (NHEJ) in an error-prone way. In plants, it could be demonstrated that the Cas9 nuclease is able to induce heritable mutations in Arabidopsis thaliana and rice. Gene targeting (GT) by homologous recombination (HR) can also be induced by DSBs. Using a natural nuclease and marker genes, we previously developed an in planta GT strategy in which both a targeting vector and targeting locus are activated simultaneously via DSB induction during plant development. Here, we demonstrate that this strategy can be used for natural genes by CRISPR/Cas-mediated DSB induction. We were able to integrate a resistance cassette into the ADH1 locus of A. thaliana via HR. Heritable events were identified using a PCR-based genotyping approach, characterised by Southern blotting and confirmed on the sequence level. A major concern is the specificity of the CRISPR/Cas nucleases. Off-target effects might be avoided using two adjacent sgRNA target sequences to guide the Cas9 nickase to each of the two DNA strands, resulting in the formation of a DSB. By amplicon deep sequencing, we demonstrate that this Cas9 paired nickase strategy has a mutagenic potential comparable with that of the nuclease, while the resulting mutations are mostly deletions. We also demonstrate the stable inheritance of such mutations in A. thaliana.