scholarly journals Chemically induced herbicide tolerance in rice by the safener metcamifen is associated with a phased stress response

2019 ◽  
Vol 71 (1) ◽  
pp. 411-421 ◽  
Author(s):  
Melissa Brazier-Hicks ◽  
Anushka Howell ◽  
Jonathan Cohn ◽  
Tim Hawkes ◽  
Gavin Hall ◽  
...  
Keyword(s):  
Gene Expression ◽  
Salicylic Acid ◽  
Phase 1 ◽  
Herbicide Tolerance ◽  
Gene Families ◽  
In Planta ◽  
Biotic And Abiotic Stresses ◽  
Chemically Induced ◽  
Inducible Genes ◽  
Similar Gene

Abstract The closely related sulphonamide safeners, metcamifen and cyprosulfamide, were tested for their ability to protect rice from clodinafop-propargyl, a herbicide normally used in wheat. While demonstrating that both compounds were equally bioavailable in planta, only metcamifen prevented clodinafop from damaging seedlings, and this was associated with the enhanced detoxification of the herbicide. Transcriptome studies in rice cultures demonstrated that whereas cyprosulfamide had a negligible effect on gene expression over a 4 h exposure, metcamifen perturbed the abundance of 590 transcripts. Changes in gene expression with metcamifen could be divided into three phases, corresponding to inductions occurring over 30 min, 1.5 h and 4 h. The first phase of gene induction was dominated by transcription factors and proteins of unknown function, the second by genes involved in herbicide detoxification, while the third was linked to cellular homeostasis. Analysis of the inducible genes suggested that safening elicited similar gene families to those associated with specific biotic and abiotic stresses, notably those elicited by abscisic acid, salicylic acid, and methyl jasmonate. Subsequent experiments with safener biomarker genes induced in phase 1 and 2 in rice cell cultures provided further evidence of similarities in signalling processes elicited by metcamifen and salicylic acid.

Interaction of Arabidopsis TGA3 and WRKY53 transcription factors on Cestrum yellow leaf curling virus (CmYLCV) promoter mediates salicylic acid-dependent gene expression in planta

Planta ◽  
2017 ◽  
Vol 247 (1) ◽  
pp. 181-199 ◽  
Author(s):  
Shayan Sarkar ◽  
Abhimanyu Das ◽  
Prashant Khandagale ◽  
Indu B. Maiti ◽  
Sudip Chattopadhyay ◽  
...  
Keyword(s):  
Gene Expression ◽  
Salicylic Acid ◽  
Transcription Factors ◽  
Yellow Leaf ◽  
In Planta ◽  
Leaf Curling

scholarly journals Bacterial Compound N,N-Dimethylhexadecylamine Modulates Expression of Iron Deficiency and Defense Response Genes in Medicago truncatula Independently of the Jasmonic Acid Pathway

Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 624 ◽  
Author(s):  
Vicente Montejano-Ramírez ◽  
Ernesto García-Pineda ◽  
Eduardo Valencia-Cantero
Keyword(s):  
Gene Expression ◽  
Salicylic Acid ◽  
Iron Deficiency ◽  
Jasmonic Acid ◽  
Pseudomonas Syringae ◽  
Medicago Truncatula ◽  
Abiotic Stresses ◽  
Biotic And Abiotic Stresses ◽  
Iron Deprivation ◽  
Iron Deficient

Plants face a variety of biotic and abiotic stresses including attack by microbial phytopathogens and nutrient deficiencies. Some bacterial volatile organic compounds (VOCs) activate defense and iron-deficiency responses in plants. To establish a relationship between defense and iron deficiency through VOCs, we identified key genes in the defense and iron-deprivation responses of the legume model Medicago truncatula and evaluated the effect of the rhizobacterial VOC N,N-dimethylhexadecylamine (DMHDA) on the gene expression in these pathways by RT-qPCR. DMHDA increased M. truncatula growth 1.5-fold under both iron-sufficient and iron-deficient conditions compared with untreated plants, whereas salicylic acid and jasmonic acid decreased growth. Iron-deficiency induced iron uptake and defense gene expression. Moreover, the effect was greater in combination with DMHDA. Salicylic acid, Pseudomonas syringae, jasmonic acid, and Botrytis cinerea had inhibitory effects on growth and iron response gene expression but activated defense genes. Taken together, our results showed that the VOC DMHDA activates defense and iron-deprivation pathways while inducing a growth promoting effect unlike conventional phytohormones, highlighting that DMHDA does not mimic jasmonic acid but induces an alternative pathway. This is a novel aspect in the complex interactions between biotic and abiotic stresses.

scholarly journals Global Gene Expression Profiles Suggest an Important Role for Nutrient Acquisition in Early Pathogenesis in a Plant Model of Pseudomonas aeruginosa Infection

2008 ◽  
Vol 74 (18) ◽  
pp. 5784-5791 ◽  
Author(s):  
Tiffany L. Weir ◽  
Valerie J. Stull ◽  
Dayakar Badri ◽  
Lily A. Trunck ◽  
Herbert P. Schweizer ◽  
...  
Keyword(s):  
Gene Expression ◽  
Pseudomonas Aeruginosa ◽  
Salicylic Acid ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Global Gene Expression ◽  
Defense Responses ◽  
N Gene ◽  
Virulence Determinants ◽  
In Planta

ABSTRACT Although Pseudomonas aeruginosa is an opportunistic pathogen that does not often naturally infect alternate hosts, such as plants, the plant-P. aeruginosa model has become a widely recognized system for identifying new virulence determinants and studying the pathogenesis of the organism. Here, we examine how both host factors and P. aeruginosa PAO1 gene expression are affected in planta after infiltration into incompatible and compatible cultivars of tobacco (Nicotiana tabacum L.). N. tabacum has a resistance gene (N) against tobacco mosaic virus, and although resistance to PAO1 infection is correlated with the presence of a dominant N gene, our data suggest that it is not a factor in resistance against PAO1. We did observe that the resistant tobacco cultivar had higher basal levels of salicylic acid and a stronger salicylic acid response upon infiltration of PAO1. Salicylic acid acts as a signal to activate defense responses in plants, limiting the spread of the pathogen and preventing access to nutrients. It has also been shown to have direct virulence-modulating effects on P. aeruginosa. We also examined host effects on the pathogen by analyzing global gene expression profiles of bacteria removed from the intracellular fluid of the two plant hosts. We discovered that the availability of micronutrients, particularly sulfate and phosphates, is important for in planta pathogenesis and that the amounts of these nutrients made available to the bacteria may in turn have an effect on virulence gene expression. Indeed, there are several reports suggesting that P. aeruginosa virulence is influenced in mammalian hosts by the availability of micronutrients, such as iron and nitrogen, and by levels of O2.

scholarly journals Agrobacteria reprogram virulence gene expression by controlled release of host-conjugated signals

2019 ◽  
Vol 116 (44) ◽  
pp. 22331-22340 ◽  
Author(s):  
Chao Wang ◽  
Fuzhou Ye ◽  
Changqing Chang ◽  
Xiaoling Liu ◽  
Jianhe Wang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Salicylic Acid ◽  
Agrobacterium Tumefaciens ◽  
Virulence Gene ◽  
Tumor Formation ◽  
Bacterial Virulence ◽  
In Planta ◽  
Virulence Gene Expression ◽  
Successful Infection ◽  
Plant Metabolite

It is highly intriguing how bacterial pathogens can quickly shut down energy-costly infection machinery once successful infection is established. This study depicts that mutation of repressor SghR increases the expression of hydrolase SghA in Agrobacterium tumefaciens, which releases plant defense signal salicylic acid (SA) from its storage form SA β-glucoside (SAG). Addition of SA substantially reduces gene expression of bacterial virulence. Bacterial vir genes and sghA are differentially transcribed at early and later infection stages, respectively. Plant metabolite sucrose is a signal ligand that inactivates SghR and consequently induces sghA expression. Disruption of sghA leads to increased vir expression in planta and enhances tumor formation whereas mutation of sghR decreases vir expression and tumor formation. These results depict a remarkable mechanism by which A. tumefaciens taps on the reserved pool of plant signal SA to reprogram its virulence upon establishment of infection.

scholarly journals Endophytic Actinobacteria Induce Defense Pathways in Arabidopsis thaliana

2008 ◽  
Vol 21 (2) ◽  
pp. 208-218 ◽  
Author(s):  
V. M. Conn ◽  
A. R. Walker ◽  
C. M. M. Franco
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Salicylic Acid ◽  
Systemic Acquired Resistance ◽  
Quantitative Polymerase Chain Reaction ◽  
In Planta ◽  
Defense Gene Expression ◽  
Streptomyces Sp ◽  
Endophytic Actinobacteria

Endophytic actinobacteria, isolated from healthy wheat tissue, which are capable of suppressing a number wheat fungal pathogens both in vitro and in planta, were investigated for the ability to activate key genes in the systemic acquired resistance (SAR) or the jasmonate/ethylene (JA/ET) pathways in Arabidopsis thaliana. Inoculation of A. thaliana (Col-0) with selected endophytic strains induced a low level of SAR and JA/ET gene expression, measured using quantitative polymerase chain reaction. Upon pathogen challenge, endophyte-treated plants demonstrated a higher abundance of defense gene expression compared with the non-endophyte-treated controls. Resistance to the bacterial pathogen Erwinia carotovora subsp. carotovora required the JA/ET pathway. On the other hand, resistance to the fungal pathogen Fusarium oxysporum involved primarily the SAR pathway. The endophytic actinobacteria appear to be able to “prime” both the SAR and JA/ET pathways, upregulating genes in either pathway depending on the infecting pathogen. Culture filtrates of the endophytic actinobacteria were investigated for the ability to also activate defense pathways. The culture filtrate of Micromonospora sp. strain EN43 grown in a minimal medium resulted in the induction of the SAR pathway; however, when grown in a complex medium, the JA/ET pathway was activated. Further analysis using Streptomyces sp. strain EN27 and defense-compromised mutants of A. thaliana indicated that resistance to E. carotovora subsp. carotovora occurred via an NPR1-independent pathway and required salicylic acid whereas the JA/ET signaling molecules were not essential. In contrast, resistance to F. oxysporum mediated by Streptomyces sp. strain EN27 occurred via an NPR1-dependent pathway but also required salicylic acid and was JA/ET independent.

scholarly journals High-throughput transcriptomic analysis of human primary hepatocyte spheroids exposed to per- and polyfluoroalkyl substances (PFAS) as a platform for relative potency characterization

2021 ◽  
Author(s):  
A Rowan-Carroll ◽  
A Reardon ◽  
K Leingartner ◽  
R Gagné ◽  
A Williams ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cholesterol Biosynthesis ◽  
Health Hazard ◽  
Biological Responses ◽  
Similar Gene Expression Profile ◽  
Transcriptional Changes ◽  
Hazard And Risk ◽  
Hepatocyte Spheroids ◽  
Similar Gene ◽  
Identify Gene Expression

Abstract Per- and poly-fluoroalkyl substances (PFAS) are widely found in the environment because of their extensive use and persistence. Although several PFAS are well studied, most lack toxicity data to inform human health hazard and risk assessment. This study focussed on four model PFAS: perfluorooctanoic acid (PFOA; 8 carbon), perfluorobutane sulfonate (PFBS; 4 carbon), perfluorooctane sulfonate (PFOS; 8 carbon), and perfluorodecane sulfonate (PFDS; 10 carbon). Human primary liver cell spheroids (pooled from 10 donors) were exposed to 10 concentrations of each PFAS and analyzed at four time-points. The approach aimed to: (1) identify gene expression changes mediated by the PFAS; (2) identify similarities in biological responses; (3) compare PFAS potency through benchmark concentration analysis; and (4) derive bioactivity exposure ratios (ratio of the concentration at which biological responses occur, relative to daily human exposure). All PFAS induced transcriptional changes in cholesterol biosynthesis and lipid metabolism pathways, and predicted PPARα activation. PFOS exhibited the most transcriptional activity and had a highly similar gene expression profile to PFDS. PFBS induced the least transcriptional changes and the highest benchmark concentration (i.e., was the least potent). The data indicate that these PFAS may have common molecular targets and toxicities, but that PFOS and PFDS are the most similar. The transcriptomic bioactivity exposure ratios derived here for PFOA and PFOS were comparable to those derived using rodent apical endpoints in risk assessments. These data provide a baseline level of toxicity for comparison with other known PFAS using this testing strategy.

scholarly journals A peroxisomal β-oxidative pathway contributes to the formation of C6–C1 aromatic volatiles in poplar

2021 ◽  
Author(s):  
Nathalie D Lackus ◽  
Axel Schmidt ◽  
Jonathan Gershenzon ◽  
Tobias G Köllner
Keyword(s):  
Cinnamic Acid ◽  
Aromatic Compounds ◽  
Populus Trichocarpa ◽  
Alternative Pathway ◽  
Gene Families ◽  
Defense Responses ◽  
In Planta ◽  
Black Cottonwood ◽  
Oxidative Pathway

AbstractBenzenoids (C6–C1 aromatic compounds) play important roles in plant defense and are often produced upon herbivory. Black cottonwood (Populus trichocarpa) produces a variety of volatile and nonvolatile benzenoids involved in various defense responses. However, their biosynthesis in poplar is mainly unresolved. We showed feeding of the poplar leaf beetle (Chrysomela populi) on P. trichocarpa leaves led to increased emission of the benzenoid volatiles benzaldehyde, benzylalcohol, and benzyl benzoate. The accumulation of salicinoids, a group of nonvolatile phenolic defense glycosides composed in part of benzenoid units, was hardly affected by beetle herbivory. In planta labeling experiments revealed that volatile and nonvolatile poplar benzenoids are produced from cinnamic acid (C6–C3). The biosynthesis of C6–C1 aromatic compounds from cinnamic acid has been described in petunia (Petunia hybrida) flowers where the pathway includes a peroxisomal-localized chain shortening sequence, involving cinnamate-CoA ligase (CNL), cinnamoyl-CoA hydratase/dehydrogenase (CHD), and 3-ketoacyl-CoA thiolase (KAT). Sequence and phylogenetic analysis enabled the identification of small CNL, CHD, and KAT gene families in P. trichocarpa. Heterologous expression of the candidate genes in Escherichia coli and characterization of purified proteins in vitro revealed enzymatic activities similar to those described in petunia flowers. RNA interference-mediated knockdown of the CNL subfamily in gray poplar (Populus x canescens) resulted in decreased emission of C6–C1 aromatic volatiles upon herbivory, while constitutively accumulating salicinoids were not affected. This indicates the peroxisomal β-oxidative pathway participates in the formation of volatile benzenoids. The chain shortening steps for salicinoids, however, likely employ an alternative pathway.

scholarly journals VipariNama: RNA viral vectors to rapidly elucidate the relationship between gene expression and phenotype

2021 ◽  
Author(s):  
Arjun Khakhar ◽  
Cecily Wang ◽  
Ryan Swanson ◽  
Sydney Stokke ◽  
Furva Rizvi ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Viral Vectors ◽  
Viral Vector ◽  
Tobacco Rattle Virus ◽  
Plant Size ◽  
Great Promise ◽  
Attractive Alternative ◽  
Gibberellin Biosynthesis ◽  
In Planta

Abstract Synthetic transcription factors have great promise as tools to help elucidate relationships between gene expression and phenotype by allowing tunable alterations of gene expression without genomic alterations of the loci being studied. However, the years-long timescales, high cost, and technical skill associated with plant transformation have limited their use. In this work we developed a technology called VipariNama (ViN) in which vectors based on the Tobacco Rattle Virus (TRV) are used to rapidly deploy Cas9-based synthetic transcription factors and reprogram gene expression in planta. We demonstrate that ViN vectors can implement activation or repression of multiple genes systemically and persistently over several weeks in Nicotiana benthamiana, Arabidopsis (Arabidopsis thaliana), and tomato (Solanum lycopersicum). By exploring strategies including RNA scaffolding, viral vector ensembles, and viral engineering, we describe how the flexibility and efficacy of regulation can be improved. We also show how this transcriptional reprogramming can create predictable changes to metabolic phenotypes, such as gibberellin biosynthesis in N. benthamiana and anthocyanin accumulation in Arabidopsis, as well as developmental phenotypes, such as plant size in N. benthamiana, Arabidopsis, and tomato. These results demonstrate how ViN vector-based reprogramming of different aspects of gibberellin signaling can be used to engineer plant size in a range of plant species in a matter of weeks. In summary, VipariNama accelerates the timeline for generating phenotypes from over a year to just a few weeks, providing an attractive alternative to transgenesis for synthetic transcription factor-enabled hypothesis testing and crop engineering.

scholarly journals The Arabidopsis mediator complex subunit 8 regulates oxidative stress responses

2021 ◽  
Author(s):  
Huaming He ◽  
Jordi Denecker ◽  
Katrien Van Der Kelen ◽  
Patrick Willems ◽  
Robin Pottie ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Salicylic Acid ◽  
Jasmonic Acid ◽  
Stress Responses ◽  
Negative Regulator ◽  
Mediator Complex ◽  
Defense Gene Expression ◽  
A Genome ◽  
Oxidative Stress Responses

Abstract Signaling events triggered by hydrogen peroxide (H2O2) regulate plant growth and defense by orchestrating a genome-wide transcriptional reprogramming. However, the specific mechanisms that govern H2O2-dependent gene expression are still poorly understood. Here, we identify the Arabidopsis Mediator complex subunit MED8 as a regulator of H2O2 responses. The introduction of the med8 mutation in a constitutive oxidative stress genetic background (catalase-deficient, cat2) was associated with enhanced activation of the salicylic acid pathway and accelerated cell death. Interestingly, med8 seedlings were more tolerant to oxidative stress generated by the herbicide methyl viologen (MV) and exhibited transcriptional hyperactivation of defense signaling, in particular salicylic acid- and jasmonic acid-related pathways. The med8-triggered tolerance to MV was manipulated by the introduction of secondary mutations in salicylic acid and jasmonic acid pathways. In addition, analysis of the Mediator interactome revealed interactions with components involved in mRNA processing and microRNA biogenesis, hence expanding the role of Mediator beyond transcription. Notably, MED8 interacted with the transcriptional regulator NEGATIVE ON TATA-LESS, NOT2, to control the expression of H2O2-inducible genes and stress responses. Our work establishes MED8 as a component regulating oxidative stress responses and demonstrates that it acts as a negative regulator of H2O2-driven activation of defense gene expression.

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