Institutional Publications
Permanent URI for this collectionhttps://ndkr-library.nipgr.ac.in/handle/123456789/11
Browse
5 results
Search Results
Item High-level production of health-beneficial glucoraphanin by multiplex editing of AOP2 gene family in mustard(John Wiley & Sons, 2025) Kumar, Pravin; Bisht, Naveen C.Intake of glucosinolates through the consumption of cruciferous vegetables has been associated with numerous health benefits. In recent decades, glucosinolate glucoraphanin has gained a lot of attention, as its hydrolysis product (sulforaphane) is known to possess numerous health-promoting benefits, including anti-cancer and chemopreventive activities. However, due to the low availability of glucoraphanin in most of the cultivated Brassica crops (except broccoli), there is an increasing interest in many laboratories around the world to manipulate the glucosinolate profile for human benefit. Here, we report the high-level production of health-beneficial glucoraphanin by CRISPR/Cas9 editing of the ALKENYL HYDROXALKYL PRODUCING 2 (BjuAOP2) gene family, displaying distinct expression profiles in the allotetraploid mustard, Brassica juncea. Multiplex editing of five BjuAOP2 homologues, using four gRNAs, provided glucoraphanin accumulation up to 41.60, 75.10, 59.21 and 27.64 μmoles/g dry weight in sprouts, microgreens, seeds and leaves, respectively, of the transgene-free BjuAOP2-edited lines, while providing a significant reduction of the anti-nutritional and goitrogenic alkenyl glucosinolates including progoitrin. The glucoraphanin enhancement in BjuAOP2-edited lines was found to be dose-dependent, wherein loss-of-function mutations in BjuAOP2.A09 and BjuAOP2.B01 homologues had a more prominent effect. The transgene-free BjuAOP2-edited lines were stable for high glucoraphanin and performed at par with the wild-type plants for various seed quality and yield parameters when tested under containment conditions in the field. The development of high-glucoraphanin mustard will help its adoption as a global superfood with health-promoting benefits and as a bioactive source of high-value sulforaphane for industrial production.Item Extra-large G-proteins influence plant response to Sclerotinia sclerotiorum by regulating glucosinolate metabolism in Brassica juncea(John Wiley & Sons, 2021) Tiwari, Ruchi; Kaur, Jagreet; Bisht, Naveen C.Heterotrimeric G-proteins are one of the highly conserved signal transducers across phyla. Despite the obvious importance of G-proteins in controlling various plant growth and environmental responses, there is no information describing the regulatory complexity of G-protein networks during pathogen response in a polyploid crop. Here, we investigated the role of extra-large G-proteins (XLGs) in the oilseed crop Brassica juncea, which has inherent susceptibility to the necrotrophic fungal pathogen Sclerotinia sclerotiorum. The allotetraploid B. juncea genome contains multiple homologs of three XLG genes (two BjuXLG1, five BjuXLG2, and three BjuXLG3), sharing a high level of sequence identity, gene structure organization, and phylogenetic relationship with the progenitors’ orthologs. Quantitative reverse transcription PCR analysis revealed that BjuXLGs have retained distinct expression patterns across plant developmental stages and on S. sclerotiorum infection. To determine the role of BjuXLG genes in the B. juncea defence response against S. sclerotiorum, RNAi-based suppression was performed. Disease progression analysis showed more rapid lesion expansion and fungal accumulation in BjuXLG-RNAi lines compared to the vector control plants, wherein suppression of BjuXLG3 homologs displayed more compromised defence response at the later time point. Knocking down BjuXLGs caused impairment of the host resistance mechanism to S. sclerotiorum, as indicated by reduced expression of defence marker genes PDF1.2 and WRKY33 on pathogen infection. Furthermore, BjuXLG-RNAi lines showed reduced accumulation of leaf glucosinolates on S. sclerotiorum infection, wherein aliphatic glucosinolates were significantly compromised. Overall, our data suggest that B. juncea XLG genes are important signalling nodes modulating the host defence pathways in response to this necrotrophic pathogen.Item Feeding behaviour of generalist pests on Brassica juncea: implication for manipulation of glucosinolate biosynthesis pathway for enhanced resistance(John Wiley & Sons, 2017) Kumar, Pawan; Augustine, Rehna; Singh, Amarjeet Kumar; Bisht, Naveen C.Differential accumulation of plant defense metabolites has been suggested to have important ecological consequence in the context of plant-insect interactions. Feeding of generalist pests on Brassica juncea showed a distinct pattern with selective exclusion of leaf margins which are high in glucosinolates. Molecular basis of this differential accumulation of glucosinolates could be explained based on differential expression profile of BjuMYB28 homologs, the major biosynthetic regulators of aliphatic glucosinolates, as evident from quantitative real-time PCR and promoter:GUS fusion studies in allotetraploid B. juncea. Constitutive over-expression of selected BjuMYB28 homologs enhanced accumulation of aliphatic glucosinolates in B. juncea. Performance of two generalist pests, Helicoverpa armigera and Spodoptera litura larvae on transgenic B. juncea plants were poor compared to wild-type plants in a no-choice experiment. Correlation coefficient analysis suggested that weight gain of H. armigera larvae was negatively correlated with gluconapin (GNA) and glucobrassicanapin (GBN) whereas that of S. litura larvae was negatively correlated with GNA, GBN and sinigrin (SIN). Our study explains the significance and possible molecular basis of differential distribution of glucosinolates in B. juncea leaves and shows the potential of over-expressing BjuMYB28 for enhanced resistance of Brassica crops against the tested generalist pests.Item Targeted silencing of BjMYB28 transcription factor gene directs development of low glucosinolate lines in oilseed Brassica juncea(John Wiley & Sons, 2013) Augustine, Rehna; Mukhopadhyay, Arundhati; Bisht, Naveen C.Brassica juncea (Indian mustard), a globally important oilseed crop, contains relatively high amount of seed glucosinolates ranging from 80 to 120 lmol/g dry weight (DW). One of the major breeding objectives in oilseed Brassicas is to improve the seed-meal quality through the development of low-seed-glucosinolate lines (<30 lmol/g DW), as high amounts of certain seed glucosinolates are known to be anti-nutritional and reduce the meal palatability. Here, we report the development of transgenic B. juncea lines having seed glucosinolates as low as 11.26 lmol/g DW, through RNAi-based targeted suppression of BjMYB28, a R2R3-MYB transcription factor family gene involved in aliphatic glucosinolate biosynthesis. Targeted silencing of BjMYB28 homologs provided significant reduction in the anti-nutritional aliphatic glucosinolates fractions, without altering the desirable nonaliphatic glucosinolate pool, both in leaves and seeds of transgenic plants. Molecular characterization of single-copy, low glucosinolate homozygous lines confirmed significant down-regulation of BjMYB28 homologs vis-a-vis enhanced accumulation of BjMYB28-specific siRNA pool. Consequently, these low glucosinolate lines also showed significant suppression of genes involved in aliphatic glucosinolate biosynthesis. The low glucosinolate trait was stable in subsequent generations of the transgenic lines with no visible off-target effects on plant growth and development. Various seed quality parameters including fatty acid composition, oil content, protein content and seed weight of the low glucosinolate lines also remained unaltered, when tested under containment conditions in the field. Our results indicate that targeted silencing of a key glucosinolate transcriptional regulator MYB28 has huge potential for reducing the glucosinolates content and improving the seed-meal quality of oilseed Brassica crops.Item Four genes encoding MYB28, a major transcriptional regulator of aliphatic glucosinolate pathway, are differentially expressed in the allopolyploid Brassica juncea(Oxford University Press, 2013) Augustine, Rehna; Majee, Manoj; Gershenzon, Jonathan; Bisht, Naveen C.Glucosinolates are Capparales-specific secondary metabolites that have immense potential in human health and agriculture. Unlike Arabidopsis thaliana, our knowledge about glucosinolate regulators in the Brassica crops is sparse. In the current study, four MYB28 homologues were identified (BjuMYB28-1,-2,-3,-4) from the polyploid Brassica juncea, and the effects of allopolyploidization on the divergence of gene sequence, structure, function, and expression were assessed. The deduced protein sequences of the four BjuMYB28 genes showed 76.1-83.1% identity with the Arabidopsis MYB28. Phylogenetic analysis revealed that the four BjuMYB28 proteins have evolved via the hybridization and duplication processes forming the B. juncea genome (AABB) from B. rapa (AA) and B. nigra (BB), while retaining high levels of sequence conservation. Mutant complementation and over-expression studies in A. thaliana showed that all four BjuMYB28 genes encode functional MYB28 proteins and resulted in similar aliphatic glucosinolate composition and content. Detailed expression analysis using qRT-PCR assays and promoter-GUS lines revealed that the BjuMYB28 genes have both tissue- and cell-specific expression partitioning in B. juncea. The two B-genome origin BjuMYB28 genes had more abundant transcripts during the early stages of plant development than the A-genome origin genes. However, with the onset of the reproductive phase, expression levels of all four BjuMYB28 increased significantly, which may be necessary for producing and maintaining high amounts of aliphatic glucosinolates during the later stages of plant development. Taken together, our results suggest that the four MYB28 genes are differentially expressed and regulated in B. juncea to play discrete though overlapping roles in controlling aliphatic glucosinolate biosynthesis.