Biology subjects

Chauhan, H.

Publications and source records attributed to Chauhan, H..

6 recordsLinked to original sources

bioRxiv2024

Seed specific overexpression of a modified wheat Or gene leads to enhanced β-carotene in rice and wheat grains

Vitamin A deficiency is a major public health problem affecting up to 50% of the worlds population, as either wheat or rice, which are poor in many essential micronutrients such as vitamin A, are major staple food crops. Biofortification of cereal crops with {beta}-carotene (provitamin A) through genetic engineering is a potential solution to overcome vitamin A deficiency. The Orange (Or) protein is involved in the regulation of carotenoid accumulation and previous studies demonstrated high carotenoid accumulation due to a single-nucleotide polymorphism (SNP) in the CDS leading to substitution of Arg to His in the OR protein results in carotenoid accumulation. In the present study, we showed that this substitution of a single amino acid at position 110 (Arg to His) of wild-type wheat TaOr (referred to as TaOrHis110) increased {beta}-carotene accumulation in transgenic wheat and rice plants overexpressing TaOrHis110 under the control of the seed-specific promoter Glu-1D1. HPLC analysis revealed increase in {beta}-carotene content in rice grain up to 8-fold in case of TP309 (japonica) cultivar, 13-fold in case of IET10364 (indica) cultivar and 7-fold in wheat cv. CPAN1676. Additionally, most of the carotenoid biosynthetic pathway genes were found to be upregulated in TaOrHis110 overexpressing seeds of TP309 and IET10364, which positively correlated with maximum increase in {beta}-carotene content.

plant biology↗

bioRxiv2024

Neurotoxic Methamphetamine Doses Alter CDCel-1 Levels and Its Interaction with Vesicular Monoamine Transporter-2 in Rat Striatum

In recent years, methamphetamine METH misuse in the US has been rapidly increasing and there is no FDA-approved pharmacotherapy for METH use disorder (MUD). In addition to being dependent on the drug, people with MUD develop a variety of neurological problems related to the toxicity of this drug. A variety of molecular mechanisms underlying METH neurotoxicity has been identified, including dysfunction of the neuroprotective protein parkin. However, it is not known whether parkin loss of function within striatal dopaminergic (DAergic) terminals translates into a decrease in DA storage capacity. This study examined the relationship between parkin, its substrate cell division cycle related-1 (CDCrel-1), and vesicular monoamine transporter-2 (VMAT2) in METH neurotoxicity in male Sprague Dawley rats. To also assess individual differences in response to METHs neurotoxic effects, a large group of rats was treated with binge METH or saline and sacrificed 1h or 24h later. This study is the first to show that binge METH alters the levels and subcellular localization of CDCrel-1 and that CDCrel-1 interacts with VMAT2 and increases its levels at the plasma membrane. Furthermore, we found wide individual differences in the responses of measured indices to METH. Proteomic analysis of VMAT-2-associated proteins revealed upregulation of several proteins involved in the exocytosis/endocytosis cycle. The results suggest that at 1h after METH binge, DAergic neurons are engaged in counteracting METH-induced toxic effects, including oxidative stress- and hyperthermia-induced inhibition of synaptic vesicle cycling, with the responses varying between individual rats. Studying CDCrel-1, VMAT2, and other proteins in large groups of outbred rats can help define individual genetic and molecular differences in responses to METH neurotoxicity which, in turn, will aid treating humans suffering from METH use disorder and its neurological consequences.

neuroscience↗

bioRxiv2024

Overexpression of barley heat stress transcription factor HvHsfA6a provide thermotolerance by thermopriming

Adverse impacts of climate change, including high temperature on cereal crop production, have been evidenced globally. In plants, heat shock factors (HSFs) are crucial components of heat stress associated rescue mechanisms and are also required for normal biological processes. Here, we functionally characterized a highly heat stress responsive HvHSFA6a in barley by developing constitutively overexpressing transgenic lines. These transgenic lines showed heat tolerant phenotype via improved photosynthesis, antioxidants and upregulation of HSPs and metabolites involved in stress amelioration and keeping thermomemory as compared to wild type plants. Global transcriptomics and ChIP sequencing revealed that HvHSFA6a orchestrates the expression of several genes through direct binding with other HSFs containing consensus HSE in their promoter regions. A GC-MS based metabolomics analysis also revealed the alterations in key metabolic processes such as carbohydrate metabolism, citric acid cycle, amino acids and secondary metabolism. Higher accumulation of key metabolites such as sucrose, galactinol, shikimate and ascorbate has been observed under both control and heat stress in transgenic lines as compared to wild type plants. Taken together, the results suggest that overexpression of HvHsfA6a prime the plants for heat stress conditions by alteration in gene expression and metabolic status. HighlightPriming is a mechanism by which plants respond to various abiotic and biotic stresses. Through multi omics approach we found that barley HsfA6a provide thermotolernce in transgenic plants through priming effect on transcriptome and metabolome.

molecular biology↗

bioRxiv2023

Characterization and Expression Analysis of Nitrate Reductase 6-1ABD Gene in Hexaploid Bread Wheat Under Different Nitrogen Regime

Nitrate reductase (NR) is the key rate-limiting enzyme of the nitrogen (N) assimilation process in plants, which has not been characterized in bread wheat under nitrogen stress, especially with respect to their homeologues. Total 9 NRs were identified and classified into 3 groups, which showed a close relationship with different wheat ancestors. The occurrence of N-responsive cis-acting regulatory elements like MYB, MYC, G-Box and GATA-motif confirmed their N-responsiveness. Expression of all the three groups of NR under N-stress revealed NR 6-1ABD group to be the most N-responsive, which was characterized further in detail. The study was carried out in two genotypes contrasting for their N-responsiveness (HD 2967: Highly responsive to applied N, and Choti Lerma: Less responsive to applied N) selected on the basis of field evaluation. Homeologous differences within a genotype were found much more than the genotypic differences of a specific homeologue coding sequence. Among the three homeologues, though NR 6-1D homeologue was found most responsive to N-stress, the contribution was maximum for this homeologue followed by NR 6-1A and least by NR 6-1B. We found that the expression of homeologues was linked to the presence of N-responsive cis- elements. All the homeologues of NR 6-1 in Choti Lerma were found less responsive to N-stress, in comparison to HD 2967, which might also be linked to N-use efficiency. Homeologous expression of NR 6-1ABD revealed negligible contribution of B-homeologue to N-stress. Homeologous differences of NR 6-1ABD was found much more than the genotypic differences. Hence, our study on wheat NR will be helpful in manipulating the specific homeologue of the NR gene in the future.

plant biology↗

bioRxiv2022

Chloroplast activity provides in vitro regeneration capability in contrasting cultivars

Existence of potent in vitro regeneration system is a prerequisite for efficient genetic transformation and functional genomics of crop plants. We know little about why only some cultivars in crop plants are tissue culture friendly. In this study, tissue culture friendly cultivar Golden Promise (GP) and tissue culture resistant DWRB91(D91) were selected as contrasting cultivars to investigate the molecular basis of regeneration efficiency. Multiomics studies involving transcriptomics, proteomics, metabolomics, and biochemical analysis were performed using GP and D91 callus to unravel the regulatory mechanisms. Transcriptomics analysis revealed 1487 differentially expressed genes (DEGs), in which 795 DEGs were upregulated and 692 DEGs were downregulated in the GP-D91 transcriptome. Genes encoding proteins localized in chloroplast and involved in ROS generation were upregulated in the embryogenic calli of GP. Moreover, proteome analysis by LC-MSMS revealed 3062 protein groups and 16989 peptide groups, out of these 1586 protein groups were differentially expressed proteins (DEPs). Eventually, GC-MS based metabolomics analysis also revealed the higher activity of plastids and alterations in key metabolic processes such as sugar metabolism, fatty acid biosynthesis, and secondary metabolism. Higher accumulation of sugars, amino acids and metabolites corresponding to lignin biosynthesis were observed in GP as compared to D91. HighlightsMulti omics analysis revealed chloroplast play crucial role in providing in vitro regeneration capability in contrasting genotypes

plant biology↗

bioRxiv2020

Processive Dynamics of the Usher Assembly Platform During Uropathogenic Escherichia coli P Pilus Biogenesis

Uropathogenic Escherichia coli (UPEC) assemble hair-like surface structures termed pili or fimbriae to initiate infection of the urinary tract. P pili mediate the adherence of UPEC to the kidney epithelium, facilitating bacterial colonization and pyelonephritis1. P pili are assembled through the conserved chaperone-usher (CU) pathway2-4. In this pathway, a dedicated chaperone facilitates the folding of nascent pilus subunits in the periplasm and an integral outer membrane (OM) protein termed the usher provides the assembly platform and secretion channel for the pilus fiber. Much of the structural and functional understanding of the CU pathway has been gained through investigations of type 1 pili, which promote UPEC binding to the bladder epithelium and the development of cystitis5. In contrast, the structural basis for P pilus biogenesis at the usher has remained elusive. This is in part due to the flexible and variable-length P pilus tip fiber, creating structural heterogeneity, as well as difficulties in isolating stable P pilus assembly intermediates from bacteria. Here, we have devised a method to circumvent these hindrances and determined cryo-EM structures of the activated PapC usher in the process of secreting two- and three-subunit P pilus assembly intermediates. These structures show processive steps in P pilus biogenesis, reveal differences between P and type 1 pili, and capture new conformational dynamics of the usher assembly machine.

microbiology↗