Department Of Botany
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Item Molecular characterization and differential expression of an aromatic heptaketide producing type III plant polyketide synthase from Himalayan rhubarb(Springer, 2022-01-15T00:00:00) Pandith, Shahzad A.; Dhar, Niha; Bhosale, Sumedha; Barvkar, Vitthal T.; Razdan, Sumeer; Shah, Manzoor A.; Lattoo, Surrinder K.Rheum australe (Himalayan Rhubarb, Polygonaceae), an endangered medicinal and vegetable herb owes its age-old remedying properties to the bio-active phyto-constituents viz. anthraquinones, stilbenoids, chromones and dietary flavonoids. Polyketide pathway primarily involving the intricate Type III polyketide synthases (PKSs) contributes to the biosynthesis of these phyto-constituents. In the present study, we perform a homology-based approach to isolate an 1176�bp full-length cds sequence of the RaALS gene showing an equitable level of sequence similarity to related Type III PKSs at both nucleic acid and amino acid levels. In silico characterization revealed the presence of highly conserved amino acid residues found in nearly all Type III PKSs including the conserved active-site residues, signature motif and cyclization pocket residues with an exception of Ile256 and Gly258. Docking studies established major interactions between the starter acetyl-CoA and RaALS. Copy number analysis suggested slender evolution in Type III PKS in R. australe having a single copy of RaALS gene. qRT-PCR analyses revealed corroboration between the higher expression of RaALS in leaves followed by stem and root with that of the metabolite concentration. Expression studies further showed a direct increase of RaALS transcripts with the growing metabolite accretion in relation to altitude suggesting a probable involvement of specific Type III PKS in biosynthesis of the major phyto-constituents. Furthermore, abiotic stressors viz. methyl jasmonate, salicylic acid and UV light enhanced RaALS transcription hinting towards its role in defense mechanism in R. australe and highlighting the significance of RaALS as a prospective target for metabolic engineering. � 2022, Korean Society for Plant Biotechnology.Item Carotenoid cleavage dioxygenases (HD-CCD1A and B) contribute as strong negative regulators of ?-carotene in Indian bread wheat (cv. HD2967)(Springer Science and Business Media Deutschland GmbH, 2021-04-16T00:00:00) Thakur, Nandita; Flowerika; Thakur, Neha; Khan, Shahirina; Pandey, Ajay K.; Tiwari, SiddharthWheat (Triticum aestivum L.) is the most common cereal crop that is considered to be deficient in provitamin A carotenoids. Carotenoids are prone to degrade into apocarotenoids by the activity of carotenoid cleavage dioxygenases (CCDs). Hence, in this study, multiple CCDs were cloned from commercial Indian wheat cultivar HD2967 to understand their role in provitamin A carotenoids degradation. The homoeolog specific expression of HD-CCD1 and HD-CCD4 at different grain filling stages revealed the higher expression of transcripts arising from the A and B subgenomes of HD-CCD1. Furthermore, the grain development stages showed a strong negative correlation of HD-CCD1A (r = ? 0.969) and B (r = ? 0.970) homoeologs expression to that of ?-carotene accumulation. It suggested that they could be potentially involved in deciding the turn-over of ?-carotene in wheat grain. Three-dimensional (3D) structures for all six homoeologs of HD-CCD1 and HD-CCD4 were predicted using maize VP14 template to gain better insight into their molecular mechanism. Ramachandran plot assessment revealed that ~ 90% of residues are in the most favoured region. Docking studies with various carotenoid substrates revealed the higher affinity of HD-CCD1A and B for ?-carotene and ?-cryptoxanthin. Bacterial complementation analysis validated the functional role of all six homoeologs with HD-CCD1B showing the highest activity followed by HD-CCD1A for ?-carotene degradation. Results of this study provide valuable insights into the characteristics of HD-CCDs in wheat and thereby justifying them (HD-CCD1A and B) as the candidate genes for employing genome editing tools for developing ?-carotene enriched wheat grains. � 2021, King Abdulaziz City for Science and Technology.Item Molecular characterization and differential expression of an aromatic heptaketide producing type III plant polyketide synthase from Himalayan rhubarb(Springer, 2022-01-15T00:00:00) Pandith, Shahzad A.; Dhar, Niha; Bhosale, Sumedha; Barvkar, Vitthal T.; Razdan, Sumeer; Shah, Manzoor A.; Lattoo, Surrinder K.Rheum australe (Himalayan Rhubarb, Polygonaceae), an endangered medicinal and vegetable herb owes its age-old remedying properties to the bio-active phyto-constituents viz. anthraquinones, stilbenoids, chromones and dietary flavonoids. Polyketide pathway primarily involving the intricate Type III polyketide synthases (PKSs) contributes to the biosynthesis of these phyto-constituents. In the present study, we perform a homology-based approach to isolate an 1176�bp full-length cds sequence of the RaALS gene showing an equitable level of sequence similarity to related Type III PKSs at both nucleic acid and amino acid levels. In silico characterization revealed the presence of highly conserved amino acid residues found in nearly all Type III PKSs including the conserved active-site residues, signature motif and cyclization pocket residues with an exception of Ile256 and Gly258. Docking studies established major interactions between the starter acetyl-CoA and RaALS. Copy number analysis suggested slender evolution in Type III PKS in R. australe having a single copy of RaALS gene. qRT-PCR analyses revealed corroboration between the higher expression of RaALS in leaves followed by stem and root with that of the metabolite concentration. Expression studies further showed a direct increase of RaALS transcripts with the growing metabolite accretion in relation to altitude suggesting a probable involvement of specific Type III PKS in biosynthesis of the major phyto-constituents. Furthermore, abiotic stressors viz. methyl jasmonate, salicylic acid and UV light enhanced RaALS transcription hinting towards its role in defense mechanism in R. australe and highlighting the significance of RaALS as a prospective target for metabolic engineering. � 2022, Korean Society for Plant Biotechnology.Item Carotenoid cleavage dioxygenases (HD-CCD1A and B) contribute as strong negative regulators of ?-carotene in Indian bread wheat (cv. HD2967)(Springer Science and Business Media Deutschland GmbH, 2021-04-16T00:00:00) Thakur, Nandita; Flowerika; Thakur, Neha; Khan, Shahirina; Pandey, Ajay K.; Tiwari, SiddharthWheat (Triticum aestivum L.) is the most common cereal crop that is considered to be deficient in provitamin A carotenoids. Carotenoids are prone to degrade into apocarotenoids by the activity of carotenoid cleavage dioxygenases (CCDs). Hence, in this study, multiple CCDs were cloned from commercial Indian wheat cultivar HD2967 to understand their role in provitamin A carotenoids degradation. The homoeolog specific expression of HD-CCD1 and HD-CCD4 at different grain filling stages revealed the higher expression of transcripts arising from the A and B subgenomes of HD-CCD1. Furthermore, the grain development stages showed a strong negative correlation of HD-CCD1A (r = ? 0.969) and B (r = ? 0.970) homoeologs expression to that of ?-carotene accumulation. It suggested that they could be potentially involved in deciding the turn-over of ?-carotene in wheat grain. Three-dimensional (3D) structures for all six homoeologs of HD-CCD1 and HD-CCD4 were predicted using maize VP14 template to gain better insight into their molecular mechanism. Ramachandran plot assessment revealed that ~ 90% of residues are in the most favoured region. Docking studies with various carotenoid substrates revealed the higher affinity of HD-CCD1A and B for ?-carotene and ?-cryptoxanthin. Bacterial complementation analysis validated the functional role of all six homoeologs with HD-CCD1B showing the highest activity followed by HD-CCD1A for ?-carotene degradation. Results of this study provide valuable insights into the characteristics of HD-CCDs in wheat and thereby justifying them (HD-CCD1A and B) as the candidate genes for employing genome editing tools for developing ?-carotene enriched wheat grains. � 2021, King Abdulaziz City for Science and Technology.Item In silico screening and molecular interaction studies of tetrahydrocannabinol and its derivatives with acetylcholine binding protein(Bentham Science Publishers B.V., 2018) Panigrahi, P.P.; Singla, Ramit; Bansal, A.; Comar, Junior M.; Jaitak, Vikas; Yennamalli, R.M; Singh, T.R.Background: Alzheimer’s disease (AD) is the fourth largest cause of death among people over 65 years of age. Accumulation of β-amyloid and cholinergic deficiency are two prominent pathological descriptions for AD. Objective: Depletion of acetylcholine at the site of its action is thought to be the prime cause of AD. It has been reported that tetrahydrocannabinol (THC) exhibits anticholinesterase activity and it has been proposed as a suitable candidate for treating neurological disorders such as AD. Methods: Using an in silico approach, including virtual screening, THC and its derivatives were docked against acetylcholine binding protein (AChBP) using AutoDock. The top-ranked molecules were studied in detail using an induced fit docking approach followed by characterization of their binding affinity, toxicity and ADME properties using TOPKAT and QikProp. Results: THC_JUIT25, a novel derivative of THC, showed maximum binding affinity and was observed as a promising candidate for performing receptor-ligand interaction studies using molecular dynamics simulation. Conclusion: In this study, we propose a novel THC derivative as a potential lead molecule in the drug development strategy for treating AD.