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1.
Plant Cell Rep ; 39(11): 1443-1465, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32789542

RESUMO

KEY MESSAGE: WsWRKY1-mediated transcriptional modulation of Withania somnifera tryptophan decarboxylase gene (WsTDC) helps to regulate fruit-specific tryptamine generation for production of withanamides. Withania somnifera is a highly valued medicinal plant. Recent demonstration of novel indolyl metabolites called withanamides in its fruits (berries) prompted us to investigate its tryptophan decarboxylase (TDC), as tryptophan is invariably a precursor for indole moiety. TDC catalyzes conversion of tryptophan into tryptamine, and the catalytic reaction constitutes a committed metabolic step for synthesis of an array of indolyl metabolites. The TDC gene (WsTDC) was cloned from berries of the plant and expressed in E. coli. The recombinant enzyme was purified and characterized for its catalytic attributes. Catalytic and structural aspects of the enzyme indicated its regulatory/rate-limiting significance in generation of the indolyl metabolites. Novel tissue-wise and developmentally differential abundance of WsTDC transcripts reflected its preeminent role in withanamide biogenesis in the fruits. Transgenic lines overexpressing WsTDC gene showed accumulation of tryptamine at significantly higher levels, while lines silenced for WsTDC exhibited considerably depleted levels of tryptamine. Cloning and sequence analysis of promoter of WsTDC revealed the presence of W-box in it. Follow-up studies on isolation of WsWRKY1 transcription factor and its overexpression in W. somnifera revealed that WsTDC expression was substantially induced by WsWRKY1 resulting in overproduction of tryptamine. The study invokes a key role of TDC in regulating the indolyl secondary metabolites through enabling elevated flux/supply of tryptamine at multiple levels from gene expression to catalytic attributes overall coordinated by WsWRKY1. This is the first biochemical, molecular, structural, physiological and regulatory description of a fruit-functional TDC.


Assuntos
Descarboxilases de Aminoácido-L-Aromático/genética , Proteínas de Plantas/genética , Triptaminas/biossíntese , Withania/genética , Withania/metabolismo , Descarboxilases de Aminoácido-L-Aromático/química , Descarboxilases de Aminoácido-L-Aromático/metabolismo , Clonagem Molecular , Dissacarídeos/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Regulação da Expressão Gênica de Plantas , Indóis/metabolismo , Modelos Moleculares , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Plantas Medicinais/genética , Plantas Medicinais/metabolismo , Regiões Promotoras Genéticas , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Triptaminas/metabolismo
2.
iScience ; 25(11): 105400, 2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36353725

RESUMO

MicroProteins (miPs) are small and single-domain containing proteins of less than 20 kDa. This domain allows microProteins to interact with compatible domains of evolutionary-related proteins and fine-tuning the key physiological pathways in several organisms. Since the first report of a microProtein in mice, numerous microProteins have been identified in plants by computational approaches. However, only a few candidates have been functionally characterized, primarily in Arabidopsis. The recent success of synthetic microProteins in modulating physiological activities in crops makes these proteins interesting candidates for crop engineering. Here, we comprehensively summarise the synthesis, mode of action, and functional roles of microProteins in plants. We also discuss different approaches used to identify plant microProteins. Additionally, we discuss novel approaches to design synthetic microProteins that can be used to target proteins regulating plant growth and development. We finally highlight the prospects and challenges of utilizing microProteins in future crop improvement programs.

3.
Ann Oper Res ; : 1-28, 2022 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-36157979

RESUMO

Monitoring buyer experience provides competitive advantages for suppliers as buyers explore the market before reaching a salesperson. Still, not many B2B suppliers monitor their buyers' expectations throughout their procurement journey, especially in MSMEs and SMEs. In addition, the inductive research on evaluating buyer experience in buyer-supplier relationships is minimal, leaving an unexplored research area. This study explores antecedents of buyer experience during the buyer-supplier relationship in MSMEs and SMEs. Further, we investigate the nature of the influence of extracted precursors on the buyer experience. Firstly, we obtain the possible antecedents from the literature on buyer-supplier experience and supplier selection criteria. We also establish hypotheses based on transaction cost theory, resource-based view (RBV), and information processing view. Secondly, we employ an investigation based on the social media analytics-based approach to uncover the antecedents of buyer experience and their nature of influence on MSMEs and SME suppliers. We found that buyer experience is influenced by sustainable orientation, management capabilities (such as crisis management and process innovation), and suppliers' technology capabilities (digital readiness, big data analytical capability).

4.
J Photochem Photobiol B ; 191: 164-174, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30640143

RESUMO

Plant development is meticulously modulated by interactions between the surrounding environment and the endogenous phytohormones. Light, as an external signal coordinates with the extensive networks of hormones inside the plant to execute its effects on growth and development. Several proteins in plants have been identified for their crucial roles in mediating light regulated development. Among these are the B-box (BBX) family of transcription factors characterized by the presence of zinc-finger B-box domain in their N-terminal region. In Arabidopsis there are 32 BBX proteins that are divided into five structural groups on the basis of the domains present. Several BBX proteins play important roles in seedling photomorphogenesis, neighbourhood detection and photoperiodic regulation of flowering. There is increasing evidence that besides light signaling BBX proteins also play integral roles in several hormone signaling pathways in plants. Here we attempt to comprehensively integrate the roles of multiple BBX proteins in various light and hormone signaling pathways. We further discuss the role of the BBX proteins in mediating crosstalk between the two signaling pathways to harmonize plant growth and development. Finally, we try to analyse the conservation of BBX genes across species and discuss the role of BBX proteins in regulating economically important traits in crop plants.


Assuntos
Luz , Reguladores de Crescimento de Plantas/fisiologia , Fatores de Transcrição/fisiologia , Fotoperíodo , Desenvolvimento Vegetal/genética , Proteínas de Plantas/fisiologia , Transdução de Sinais/genética
5.
PLoS One ; 8(9): e74777, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24086372

RESUMO

Withania somnifera is one of the most reputed medicinal plants of Indian systems of medicine synthesizing diverse types of secondary metabolites such as withanolides, alkaloids, withanamides etc. Present study comprises cloning and E. coli over-expression of a tropinone reductase gene (WsTR-I) from W. somnifera, and elucidation of biochemical characteristics and physiological role of tropinone reductase enzyme in tropane alkaloid biosynthesis in aerial tissues of the plant. The recombinant enzyme was demonstrated to catalyze NADPH-dependent tropinone to tropine conversion step in tropane metabolism, through TLC, GC and GC-MS-MS analyses of the reaction product. The functionally active homodimeric ~60 kDa enzyme catalyzed the reaction in reversible manner at optimum pH 6.7. Catalytic kinetics of the enzyme favoured its forward reaction (tropine formation). Comparative 3-D models of landscape of the enzyme active site contours and tropinone binding site were also developed. Tissue-wide and ontogenic stage-wise assessment of WsTR-I transcript levels revealed constitutive expression of the gene with relatively lower abundance in berries and young leaves. The tissue profiles of WsTR-I expression matched those of tropine levels. The data suggest that, in W. somnifera, aerial tissues as well possess tropane alkaloid biosynthetic competence. In vivo feeding of U-[(14)C]-sucrose to orphan shoot (twigs) and [(14)C]-chasing revealed substantial radiolabel incorporation in tropinone and tropine, confirming the de novo synthesizing ability of the aerial tissues. This inherent independent ability heralds a conceptual novelty in the backdrop of classical view that these tissues acquire the alkaloids through transportation from roots rather than synthesis. The TR-I gene expression was found to be up-regulated on exposure to signal molecules (methyl jasmonate and salicylic acid) and on mechanical injury. The enzyme's catalytic and structural properties as well as gene expression profiles are discussed with respect to their physiological overtones.


Assuntos
Oxirredutases do Álcool/genética , Regulação Enzimológica da Expressão Gênica , Especificidade de Órgãos/genética , Proteínas Recombinantes/metabolismo , Tropanos/metabolismo , Withania/enzimologia , Withania/genética , Oxirredutases do Álcool/química , Oxirredutases do Álcool/isolamento & purificação , Oxirredutases do Álcool/metabolismo , Sequência de Aminoácidos , Biocatálise , Vias Biossintéticas/genética , Clonagem Molecular , Eletroforese em Gel de Poliacrilamida , Cromatografia Gasosa-Espectrometria de Massas , Genes de Plantas , Concentração de Íons de Hidrogênio , Cinética , Modelos Moleculares , Dados de Sequência Molecular , Filogenia , Extratos Vegetais , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Análise de Sequência de Proteína , Homologia Estrutural de Proteína , Especificidade por Substrato
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