Publications by authors named "Akshay K Pradhan"

Brassica carinata (BBCC) commonly referred to as Ethiopian mustard is a natural allotetraploid containing the genomes of Brassica nigra (BB) and Brassica oleracea (CC). It is an oilseed crop endemic to the northeastern regions of Africa. Although it is under limited cultivation, B.

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Glucosinolate content in the two major oilseed Brassica crops-rapeseed and mustard has been reduced to the globally accepted Canola quality level (<30 μmoles/g of seed dry weight, DW), making the protein-rich seed meal useful as animal feed. However, the overall lower glucosinolate content in seeds as well as in the other parts of such plants renders them vulnerable to biotic challenges. We report CRISPR/Cas9-based editing of glucosinolate transporter (GTR) family genes in mustard (Brassica juncea) to develop ideal lines with the desired low seed glucosinolate content (SGC) while maintaining high glucosinolate levels in the other plant parts for uncompromised plant defence.

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Genetic mapping of some key plant architectural traits in a vegetable type and an oleiferous B. juncea cross revealed QTL and candidate genes for breeding more productive ideotypes. Brassica juncea (AABB, 2n = 36), commonly called mustard, is an allopolyploid crop of recent origin but contains considerable morphological and genetic variation.

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Cryptochrome 2 (CRY2) perceives blue/UV-A light and regulates photomorphogenesis in plants. However, besides Arabidopsis, CRY2 has been functionally characterized only in native species of japonica rice and tomato. In the present study, the BnCRY2a, generating a relatively longer cDNA and harboring an intron in its 5'UTR, has been characterized in detail.

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Seed size/weight is a multigenic trait that is governed by complex transcriptional regulatory pathways. An understanding of the genetic basis of seed size is of great interest in the improvement of seed yield and quality in oilseed crops. A global transcriptome analysis was performed at the initial stages of seed development in two lines of , small-seeded EH-2 and large-seeded PJ.

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The exploitation of heterosis through hybrid breeding is one of the major breeding objectives for productivity increase in crop plants. This research analyzes the genetic basis of heterosis in by using a doubled haploid (DH) mapping population derived from F between two heterotic inbred parents, one belonging to the Indian and the other belonging to the east European gene pool, and their two corresponding sets of backcross hybrids. An Illumina Infinium Brassica 90K SNP array-based genetic map was used to identify yield influencing quantitative trait loci (QTL) related to plant architecture, flowering, and silique- and seed-related traits using five different data sets from multiple trials, allowing the estimation of additive and dominance effects, as well as digenic epistatic interactions.

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Article Synopsis
  • Brassica crops contain health-promoting compounds called glucosinolates, which are being studied for their benefits.
  • This research utilized Visible-Near InfraRed Spectroscopy (Vis-NIRS) to analyze 641 types of Brassica juncea for different glucosinolate components and developed effective prediction models.
  • The combined Vis-NIRS model demonstrated high accuracy and reliability in predicting glucosinolate content, making it a valuable tool for screening and quality control in Brassica oilseed production.
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  • Brassica nigra, or black mustard, is an important condiment crop in India and a progenitor of the oilseed crop B. juncea.
  • The genome assembly of the B. nigra variety Sangam was performed using advanced sequencing techniques, resulting in a comprehensive assembly covering about 515.4 Mb and revealing 57,249 protein-coding genes.
  • The study found significant gene colinearity with B. juncea, while highlighting structural differences in gene arrangements within the A, B, and C genomes of U's triangle, leading to a proposed new nomenclature for B. nigra pseudochromosomes.
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  • Brassica juncea, or mustard, is an allopolyploid formed from the diploid species B. rapa and B. nigra, and the study focuses on the genome assembly of a specific variety called Varuna.
  • Using advanced sequencing techniques, researchers created a high-quality genome assembly with a large N50 value, improving upon previous drafts and validating the B genome through genetic mapping.
  • The analysis reveals significant differences in transposons, gene content, and gene arrangement between the A and B genomes, which can aid in breeding efforts for mustard varieties grown in South Asia.
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  • - White rust, caused by an oomycete, poses a significant threat to oilseed mustard, especially in the highly susceptible Indian gene pool, while some East European lines show resistance mapped to specific genomic regions.
  • - A new resistance locus against isolate AcB1 has been identified in a Chinese mustard line (Tumida), using a mapping population derived from a cross with a susceptible Indian line (Varuna) and involving over 8,000 genetic markers.
  • - The candidate gene for resistance is a CC-NBS-LRR (CNL) type R gene that differs in structure between resistant and susceptible varieties, revealing potential similarities between resistance genes across different mustard lines.
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  • BjuWRR1 is a newly identified resistance gene from a Brassica juncea line that was validated to provide protection against the white rust disease caused by Albugo candida, a major threat to crucifer crops.
  • Earlier research mapped a resistance locus, AcB1-A5.1, in a specific east European Brassica juncea line, Donskaja-IV, which showed complete resistance to various isolates of the pathogen.
  • The BjuWRR1 gene was genetically transformed into a susceptible Indian line, Varuna, successfully conferring full resistance, marking it as the first resistance gene identified for white rust in Brassica species.
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Increasing oil content in oilseed mustard () is a major breeding objective-more so, in the lines that have "0" erucic acid content (< 2% of the seed oil) as earlier studies have shown negative pleiotropic effect of erucic acid loci on the oil content, both in oilseed mustard and rapeseed. We report here QTL analysis of oil content in eight different mapping populations involving seven different parents-including a high oil content line J8 (~49%). The parental lines of the mapping populations contained wide variation in oil content and erucic acid content.

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Quantitative disease resistance (QDR) is the predominant form of resistance against necrotrophic pathogens. The genes and mechanisms underlying QDR are not well known. In the current study, the Arabidopsis-Alternaria brassicae pathosystem was used to uncover the genetic architecture underlying resistance to A.

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Sinapine is a major anti-nutritive compound that accumulates in the seeds of Brassica species. When ingested, sinapine imparts gritty flavuor in meat and milk of animals and fishy odor to eggs of brown egg layers, thereby compromising the potential use of the valuable protein rich seed meal. Sinapine content in Brassica juncea germplasm ranges from 6.

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, a necrotrophic fungal pathogen, causes blight, one of the most important diseases of oleiferous crops. The current study utilized as a model to decipher the genetic architecture of defense against . Significant phenotypic variation that was largely genetically determined was observed among accessions in response to pathogen challenge.

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Polyploidy, the possession of multiple sets of chromosomes, has been a predominant factor in the evolution and success of the angiosperms. Although artificially formed allopolyploids show a high rate of genome rearrangement, the genomes of cultivars and germplasm used for crop breeding were assumed stable and genome structural variation under the artificial selection process of commercial breeding has remained little studied. Here, we show, using a repurposed visualization method based on transcriptome sequence data, that genome structural rearrangement occurs frequently in varieties of three polyploid crops (oilseed rape, mustard rape and bread wheat), meaning that the extent of genome structural variation present in commercial crops is much higher than expected.

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Seed weight QTL identified in different populations were synthesized into consensus QTL which were shown to harbor candidate genes by in silico mapping. Allelic variation inferred would be useful in breeding B. juncea lines with high seed weight.

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Article Synopsis
  • - Sinigrin, a type of glucosinolate derived from methionine, has significant pharmacological benefits, but the gene responsible for its biosynthesis in certain Brassica species remains unclear.
  • - Researchers identified and characterized the CYP79F1 gene in B. juncea, which is crucial for the initial step in glucosinolate biosynthesis; it showed a polymorphism between two lines, one that produces sinigrin (Varuna) and one that does not (Heera).
  • - They validated the function of CYP79F1 through genetic studies and transgenic approaches, successfully demonstrating that introducing this gene into a sinigrin-free B. juncea line led to the synthesis of sinigrin, confirming its
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QTL mapping by two DH mapping populations deciphered allelic variations for five different seed glucosinolate traits in B. juncea. Allelic variations for five different seed glucosinolate (GS) traits, namely % propyl, % butyl, % pentyl, aliphatics and total GS content were studied through QTL analysis using two doubled haploid (DH) mapping populations.

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The multiple BjuCYP83A1 genes formed as a result of polyploidy have retained cell-, tissue-, and condition-specific transcriptional sub-functionalization to control the complex aliphatic glucosinolates biosynthesis in the allotetraploid Brassica juncea. Glucosinolates along with their breakdown products are associated with diverse roles in plant metabolism, plant defense and animal nutrition. CYP83A1 is a key enzyme that oxidizes aliphatic aldoximes to aci-nitro compounds in the complex aliphatic glucosinolate biosynthetic pathway.

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Genetic locus for tetralocular ovary (tet-o) in Brassica rapa was identified and it was shown that the number of locules and width of silique are associated. Brassica rapa is a highly polymorphic species containing many vegetables and oleiferous types. An interesting group of oleiferous types is the yellow sarson group (subspecies trilocularis) grown mostly in eastern India.

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Article Synopsis
  • Brassica species, part of the Brassiceae tribe, evolved through two rounds of polyploidization, leading to the formation of both diploid and allopolyploid species from a common hexaploid ancestor.
  • Molecular studies support the theory of a genome triplication origin for these species and show a complex evolutionary history involving distinct lineages.
  • Analysis of genetic data revealed significant divergence timelines among the species, indicating that at least two independent genome triplication events contributed to the development of different Brassica lineages.
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Identification of the candidate gene responsible for the seed coat colour variation in Brassica juncea was undertaken following an earlier study where two independent loci (BjSc1 and BjSc2) were mapped to two linkage groups, LG A9 and B3 (Padmaja et al. in Theor Appl Genet 111:8-14, 2005). The genome search from BRAD data for the presence of flavonoid genes in B.

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