Project description:Secondary metabolites play a key role in coordinating ecology and defense strategies of plants. Diversity of these metabolites arise by conjugation of core structures with diverse chemical moieties, such as sugars in glycosylation. Active pools of phytohormones, including those involved in plant stress response are also regulated by glycosylation. While, much is known about the enzymes involved in glycosylation, we know little about their regulation or coordination with other processes. We characterized the flavonoid pathway transcription factor, TRANSPARENT TESTA 8 (TT8) in Arabidopsis thaliana, using an integrative omics strategy. This approach provides a systems level understanding of the cellular machinery that is used to generate metabolite diversity by glycosylation. Metabolomics analysis of TT8 loss-of-function and inducible overexpression lines showed that TT8 coordinates glycosylation of not only flavonoids, but also nucleotides, thus, implicating TT8 in regulating pools of activated nucleotide sugars. Transcriptome and promoter network analyses revealed that TT8 regulome included sugar transporters, proteins involved in sugar binding and sequestration, and a number of carbohydrate active enzymes. Importantly, TT8 affects stress response, along with brassinosteroid and jasmonic acid biosynthesis, by directly binding to the promoters of key genes of these processes. This combined effect on metabolites glycosylation and stress hormones by TT8 inducible overexpression led to significant increase in tolerance towards multiple abiotic and biotic stresses. Conversely, loss of TT8 leads to increased sensitivity to these stresses. Thus, the transcription factor TT8 is an integrator of secondary metabolism and stress response. These findings provide novel approaches to improve broad-spectrum stress tolerance. Gene expression analysis for 6-day old Arabidopsis thaliana seedling were performed for TT8 loss-of-function line, tt8-3 (in Ws background), and its wild type background control, Ws. Two independent biological replicates for each line were hybridized onto two slides of Agilent SurePrint G2 Agilent Arabidopsis V4 (4x44K), with each slide having two technical replicates for each line. Contributors: Amit Rai, Shivshankar Umashankar, Megha, Lim Boon Kiat, Johanan Aow Shao Bing, Sanjay Swarup.
Project description:Secondary metabolites play a key role in coordinating ecology and defense strategies of plants. Diversity of these metabolites arise by conjugation of core structures with diverse chemical moieties, such as sugars in glycosylation. Active pools of phytohormones, including those involved in plant stress response are also regulated by glycosylation. While, much is known about the enzymes involved in glycosylation, we know little about their regulation or coordination with other processes. We characterized the flavonoid pathway transcription factor, TRANSPARENT TESTA 8 (TT8) in Arabidopsis thaliana, using an integrative omics strategy. This approach provides a systems level understanding of the cellular machinery that is used to generate metabolite diversity by glycosylation. Metabolomics analysis of TT8 loss-of-function and inducible overexpression lines showed that TT8 coordinates glycosylation of not only flavonoids, but also nucleotides, thus, implicating TT8 in regulating pools of activated nucleotide sugars. Transcriptome and promoter network analyses revealed that TT8 regulome included sugar transporters, proteins involved in sugar binding and sequestration, and a number of carbohydrate active enzymes. Importantly, TT8 affects stress response, along with brassinosteroid and jasmonic acid biosynthesis, by directly binding to the promoters of key genes of these processes. This combined effect on metabolites glycosylation and stress hormones by TT8 inducible overexpression led to significant increase in tolerance towards multiple abiotic and biotic stresses. Conversely, loss of TT8 leads to increased sensitivity to these stresses. Thus, the transcription factor TT8 is an integrator of secondary metabolism and stress response. These findings provide novel approaches to improve broad-spectrum stress tolerance.
Project description:Secondary metabolites play a key role in coordinating ecology and defense strategies of plants. Diversity of these metabolites arise by conjugation of core structures with diverse chemical moieties, such as sugars in glycosylation. Active pools of phytohormones, including those involved in plant stress response are regulated by glycosylation. While, much is known about glycosylation enzymes, we know little about their regulation or coordination with other biological processes. We characterized the flavonoid pathway transcription factor, TRANSPARENT TESTA 8 (TT8) in Arabidopsis thaliana, using an integrative 'omics strategy to provide a systems level understanding of the cellular machinery used to generate metabolite diversity by glycosylation. Metabolomics analysis of loss-of-function and inducible overexpression lines of TT8 showed that it coordinates glycosylation of not only flavonoids, but also nucleotides, thus, implicating TT8 in regulating pools of activated sugars. Transcriptome and promoter network analyses revealed that TT8 regulome included sugar transporters, sugar binding and sequestration proteins, and carbohydrate active enzymes. Interestingly, TT8 also affects brassinosteroid and jasmonic acid biosynthesis by directly binding to the promoters of key genes of these two pathways. This combined effect on metabolites glycosylation and stress hormones by TT8 overexpression lead to significant increase in tolerance towards multiple abiotic and biotic stresses. Conversely, loss of TT8 leads to increased sensitivity to these stresses. Thus, TT8 is an integrator of secondary metabolism and stress response.
Project description:Down regulation of qptgene in arabidopsis-Regulation of NAD biosynthesis in Arabidopsis : role of quinolinate phosphoribosyltransferase.
Project description:Brassinosteroids (BRs) are endogenous plant hormones and essential for normal plant growth and development. MicroRNAs (miRNAs) of Arabidopsis thaliana are involved in mediating cell proliferation in leaves, stress tolerance, and root development. The specifics of BRs mechanisms involving miRNAs are unknown. To explore the role of miRNAs in BR-mediated pathways, we analyzed differences in miRNA profiles between control (mock solution) and 24-epibrassinolide (EBR) treatments from customized miRNA microarrays.
Project description:Several fungi have been reported to form intimate bonds with plants. These close mutual relationships can provide physiological benefits to the interacting organisms, including the improvement of nutrient assimilation or enhanced stress tolerance. The root-colonizing fungus Fusarium sp. strain K-23 is known to successfully colonize tomato roots. Previous studies highlighted the promotion of plant biomass production and stress tolerance of tomato plants infected with the K-23. However, up to data, nothing is known about the effect of this fungus on the model plant Arabidopsis thaliana. We here report the comparative analysis of the effect of mock- and K-23-infected wild-type Arabidopsis plants (Col-0) in the abscence and presence of moderate salt stress conditions (50 mM NaCl). Our data provide evidence for a profound effect of K-23 on root hair elongation through the activation of a regulatory network that includes several plant hormones. Intriguingly, the fungus suppresses gibberellic acid biosynthesis which, in turn, promotes root hair elongation.