Gene Expression Profiling Reveals Enhanced Defense Responses in an Invasive Weed Compared to Its Native Congener during Pathogenesis

Invasive plants are a huge burden on the environment, and modify local ecosystems by affecting the indigenous biodiversity. Invasive plants are generally less affected by pathogens, although the underlying molecular mechanisms responsible for their enhanced resistance are unknown. We investigated expression profiles of three defense hormones (salicylic acid, jasmonic acid, and ethylene) and their associated genes in the invasive weed, Alternanthera philoxeroides, and its native congener, A. sessilis, after inoculation with Rhizoctonia solani. Pathogenicity tests showed significantly slower disease progression in A. philoxeroides compared to A. sessilis. Expression analyses revealed jasmonic acid (JA) and ethylene (ET) expressions were differentially regulated between A. philoxeroides and A. sessilis, with the former having prominent antagonistic cross-talk between salicylic acid (SA) and JA, and the latter showing weak or no cross-talk during disease development. We also found that JA levels decreased and SA levels increased during disease development in A. philoxeroides. Variations in hormonal gene expression between the invasive and native species (including interspecific differences in the strength of antagonistic cross-talk) were identified during R. solani pathogenesis. Thus, plant hormones and their cross-talk signaling may improve the resistance of invasive A. philoxeroides to pathogens, which has implications for other invasive species during the invasion process.

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Integrated Transcriptome Analysis Reveals Plant Hormones Jasmonic Acid and Salicylic Acid Coordinate Growth and Defense Responses upon Fungal Infection in Poplar

Biomolecules ◽

10.3390/biom9010012 ◽

2019 ◽

Vol 9 (1) ◽

pp. 12 ◽

Cited By ~ 24

Author(s):

Jie Luo ◽

Wenxiu Xia ◽

Pei Cao ◽

Zheng’ang Xiao ◽

Yan Zhang ◽

...

Keyword(s):

Gene Expression ◽

Salicylic Acid ◽

Jasmonic Acid ◽

Fungal Infection ◽

Plant Hormones ◽

Expression Profiles ◽

Defense Responses ◽

Expression Data ◽

Term Analysis ◽

Fungal Defense

Plants have evolved a sophisticated system to respond to various stresses. Fungal attack or infection is one of the most important biotic stresses for most plants. During the defense response to fungal infection, the plant hormones jasmonic acid (JA) and salicylic acid (SA) play critical roles. Here, gene expression data on JA/SA treatments and Melampsora larici-populina (MLP) infection were generated. Integrated transcriptome analyses of these data were performed, and 943 genes in total were identified as common responsive genes (CRG). Gene ontology (GO) term analysis revealed that the genes from CRG are generally involved in the processes of stress responses, metabolism, and growth and development. The further cluster analysis of the CRG identified a set of core genes that are involved in the JA/SA-mediated response to fungal defense with distinct gene expression profiles upon JA/SA treatment, which highlighted the different effects of these two hormones on plant fungal defenses. The modifications of several pathways relative to metabolism, biotic stress, and plant hormone signal pathways suggest the possible roles of JA/SA on the regulation of growth and defense responses. Co-expression modules (CMs) were also constructed using the poplar expression data on JA, SA, M. larici-populina, Septoria musiva, and Marssonina brunnea treatment or infection. A total of 23 CMs were constructed, and different CMs clearly exhibited distinct biological functions, which conformably regulated the concerted processes in response to fungal defense. Furthermore, the GO term analysis of different CMs confirmed the roles of JA and SA in regulating growth and defense responses, and their expression profiles suggested that the growth ability was reduced when poplar deployed defense responses. Several transcription factors (TFs) among the CRG in the co-expression network were proposed as hub genes in regulating these processes. According to this study, our data finely uncovered the possible roles of JA/SA in regulating the balance between growth and defense responses by integrating multiple hormone signaling pathways. We were also able to provide more knowledge on how the plant hormones JA/SA are involved in the regulation of the balance between growth and plant defense.

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

Applied and Environmental Microbiology ◽

10.1128/aem.00860-08 ◽

2008 ◽

Vol 74 (18) ◽

pp. 5784-5791 ◽

Cited By ~ 18

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.

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Arabidopsis thaliana EDS4 Contributes to Salicylic Acid (SA)-Dependent Expression of Defense Responses: Evidence for Inhibition of Jasmonic Acid Signaling by SA

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2000.13.5.503 ◽

2000 ◽

Vol 13 (5) ◽

pp. 503-511 ◽

Cited By ~ 114

Author(s):

Vaijayanti Gupta ◽

Michael G. Willits ◽

Jane Glazebrook

Keyword(s):

Gene Expression ◽

Salicylic Acid ◽

Jasmonic Acid ◽

Pseudomonas Syringae ◽

Systemic Acquired Resistance ◽

Acquired Resistance ◽

Defense Responses ◽

Avirulence Gene ◽

Signal Molecule ◽

Resistance Response

The Arabidopsis enhanced disease susceptibility 4 (eds4) mutation causes enhanced susceptibility to infection by the bacterial pathogen Pseudomonas syringae pv. Maculicola ES4326 (Psm ES4326). Gene-for-gene resistance to bacteria carrying the avirulence gene avrRpt2 is not significantly affected by eds4. Plants homozygous for eds4 exhibit reduced expression of the pathogenesis-related gene PR-1 after infection by Psm ES4326, weakened responses to treatment with the signal molecule salicylic acid (SA), impairment of the systemic acquired resistance response, and reduced accumulation of SA after infection with Psm ES4326. These phenotypes indicate that EDS4 plays a role in SA-dependent signaling. SA has been shown to have a negative effect on activation of gene expression by the signal molecule jasmonic acid (JA). Two mutations that cause reduced SA levels, eds4 and pad4, cause heightened responses to inducers of JA-dependent gene expression, providing genetic evidence to support the idea that SA interferes with JA-dependent signaling. Two possible working models of the role of EDS4 in governing activation of defense responses are presented.

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Transcriptional Dynamics of the Salicylic Acid Response and its Interplay with the Jasmonic Acid Pathway

10.1101/742742 ◽

2019 ◽

Cited By ~ 3

Author(s):

Richard Hickman ◽

Marciel Pereira Mendes ◽

Marcel C. Van Verk ◽

Anja J.H. Van Dijken ◽

Jacopo Di Sora ◽

...

Keyword(s):

Gene Expression ◽

Salicylic Acid ◽

Jasmonic Acid ◽

Expression Profiles ◽

Plant Immunity ◽

Regulatory Elements ◽

Transcriptional Reprogramming ◽

Transcriptional Changes ◽

Acid Pathway ◽

Defense Studies

AbstractThe phytohormone salicylic acid (SA) is a central regulator of plant immunity. Antagonistic and synergistic actions between SA and other defense-associated hormones like jasmonic acid (JA) play key roles in determining the outcome of the plant immune response. To obtain a deeper understanding of SA-mediated transcriptional reprogramming and SA/JA crosstalk, we generated a high-resolution time series of gene expression from Arabidopsis leaves treated with SA alone and a combination of SA and methyl JA (MeJA), sampled at 14 time points over a 16-h period. We found that approximately one-third of the Arabidopsis genome was differentially expressed in response to SA, and temporal changes in gene expression could be partitioned into 45 distinct clusters of process-specific coregulated genes, linked to specific cis-regulatory elements and binding of transcription factors (TFs). Integration of our expression data with information on TF-DNA binding allowed us to generate a dynamic gene regulatory network model of the SA response, recovering known regulators and identifying novel ones. We found that 12% of SA-responsive genes and 69% of the MeJA-responsive genes exhibited antagonistic or synergistic expression levels in the combination treatment. Multi-condition co-clustering of the single- and combined-hormone expression profiles predicted underlying regulatory mechanisms in signal integration. Finally, we identified the TFs ANAC061 and ANAC090 as negative regulators of SA pathway genes and defense against biotrophic pathogens. Collectively, our data provide an unprecedented level of detail about transcriptional changes during the SA response and SA/JA crosstalk, serving as a valuable resource for systems-level network studies and functional plant defense studies.

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Effects of abscisic acid, jasmonic acid and salicylic acid on the content of phytochemicals and their gene expression profiles and biological activity in turnip (Brassica rapa ssp. rapa)

Plant Growth Regulation ◽

10.1007/s10725-016-0178-7 ◽

2016 ◽

Vol 80 (3) ◽

pp. 377-390 ◽

Cited By ~ 19

Author(s):

Muthu Thiruvengadam ◽

Venkitasamy Baskar ◽

Seung-Hyun Kim ◽

Ill-Min Chung

Keyword(s):

Gene Expression ◽

Biological Activity ◽

Salicylic Acid ◽

Abscisic Acid ◽

Jasmonic Acid ◽

Brassica Rapa ◽

Expression Profiles ◽

Gene Expression Profiles

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The Arabidopsis mediator complex subunit 8 regulates oxidative stress responses

The Plant Cell ◽

10.1093/plcell/koab079 ◽

2021 ◽

Cited By ~ 1

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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Restoration of Defective Cross Talk in ssi2 Mutants: Role of Salicylic Acid, Jasmonic Acid, and Fatty Acids in SSI2-Mediated Signaling

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2003.16.11.1022 ◽

2003 ◽

Vol 16 (11) ◽

pp. 1022-1029 ◽

Cited By ~ 42

Author(s):

Pradeep Kachroo ◽

Aardra Kachroo ◽

Ludmila Lapchyk ◽

David Hildebrand ◽

Daniel F. Klessig

Keyword(s):

Cell Death ◽

Salicylic Acid ◽

Jasmonic Acid ◽

Cross Talk ◽

Pr Genes ◽

Exogenous Application ◽

Basal Level Expression ◽

Sa Signaling ◽

Spontaneous Cell Death

The Arabidopsis mutants ssi2 and fab2 are defective in stearoyl ACP desaturase, which causes altered salicylic acid (SA)- and jasmonic acid (JA)-mediated defense signaling. Both ssi2 and fab2 plants show spontaneous cell death, express PR genes constitutively, accumulate high levels of SA, and exhibit enhanced resistance to bacterial and oomycete pathogens. In contrast to constitutive activation of the SA pathway, ssi2 and fab2 plants are repressed in JA-mediated induction of the PDF1.2 gene, which suggests that the SSI2-mediated signaling pathway modulates cross talk between the SA and JA pathways. In this study, we have characterized two recessive nonallelic mutants in the ssi2 background, designated as rdc (restorer of defective cross talk) 2 and rdc8. Both ssi2 rdc mutants are suppressed in constitutive SA signaling, show basal level expression of PR-1 gene, and induce high levels of PDF1.2 in response to exogenous application of JA. Interestingly, while the rdc8 mutation completely abolishes spontaneous cell death in ssi2 rdc8 plants, the ssi2 rdc2 plants continue to show some albeit reduced cell death. Fatty acid (FA) analysis showed a reduction in 16:3 levels in ssi2 rdc8 plants, which suggests that this mutation may limit the flux of FAs into the pro-karyotic pathway of glycerolipid biosynthesis. Both rdc2 and rdc8 continue to accumulate high levels of 18:0, which suggests that 18:0 levels were responsible for neither constitutive SA signaling nor repression of JA-induced expression of the PDF1.2 gene in ssi2 plants. We also analyzed SA and JA responses of the fab2-derived shs1 mutant, which accumulates levels of 18:0 over 50% lower than those in the fab2 plants. Even though fab2 shs1 plants were morphologically bigger than fab2 plants, they expressed PR genes constitutively, showed HR-like cell death, and accumulated elevated levels of SA. However, unlike the ssi2 rdc plants, fab2 shs1 plants were unable to induce high levels of PDF1.2 expression in response to exogenous application of JA. Together, these results show that defective cross talk in ssi2 can be restored by second site mutations and is independent of morphological size of the plants, cell death, and elevated levels of 18:0.

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Salicylic acid and jasmonic acid can suppress green and blue moulds of citrus fruit and induce the activity of polyphenol oxidase and peroxidase

Folia Horticulturae ◽

10.2478/fhort-2019-0014 ◽

2019 ◽

Vol 31 (1) ◽

pp. 195-204 ◽

Cited By ~ 7

Author(s):

Anam Moosa ◽

Shahbaz Talib Sahi ◽

Sajid Aleem Khan ◽

Aman Ullah Malik

Keyword(s):

Salicylic Acid ◽

Jasmonic Acid ◽

Disease Severity ◽

Polyphenol Oxidase ◽

Disease Incidence ◽

Citrus Fruit ◽

Disease Development ◽

Post Harvest ◽

Blue Mould ◽

Green Mould

AbstractThe ability of salicylic acid and jasmonic acid to suppress post-harvest infection with green mould Penicillium digitatum and blue mould P. italicum on three citrus species Citrus reticulata ‘Kinnow’, C. limon ‘Meyer Lemon’, and C. limetta ‘Mosambi’ was evaluated in a dose-response study. Salicylic acid (SA) and jasmonic acid (JA) were applied to the fruits as a post-harvest dip treatment followed by wound inoculation with the pathogens. Both resistance inducers caused a significantly lower disease severity compared with the infected but non-treated control, whereas disease incidence was not significantly lower than in the control. The efficacy of both SA and JA in reducing disease severity was concentration-dependent; the use of higher concentrations resulted in a greater degree of suppression. All the Citrus species tested in this study showed different responses in terms of disease development. C. limon ‘Meyer Lemon’ showed the highest disease development, and C. limetta ‘Mosambi’ the lowest. To get an insight into the mechanisms underlying the increase in resistance, the activity of defence-related enzymes – peroxidase (POD) and polyphenol oxidase (PPO) – was recorded in SA- and JA-treated fruit peelings. The activity of both enzymes was directly proportional to the concentration of the SA and JA applications. The highest activity of PPO and POD was observed in C. reticulata ‘Kinnow’ and the lowest in C. limon ‘Meyer Lemon’ fruits. This study is the first to document an increase in the activity of PPO and POD in SA- and JA-treated Citrus species in the presence of blue mould and green mould pathogens.

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

Plants ◽

10.3390/plants9050624 ◽

2020 ◽

Vol 9 (5) ◽

pp. 624 ◽

Cited By ~ 1

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.

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