Salicylic Acid
323 views | +0 today
Follow
Salicylic Acid
Salicylic Acid
Curated by tianxing84
Your new post is loading...
Your new post is loading...
Rescooped by tianxing84 from Plant-Microbe Interaction
Scoop.it!

Trends in Plant Science - Localised ABA signalling mediates root growth plasticity


Via Guogen Yang
more...
Guogen Yang's curator insight, October 4, 2013 10:34 PM

Two recent reports show that cellular abscisic acid (ABA) signalling, together with other phytohormone signalling pathways, is crucial for salt-regulated root growth dynamics. Here we discuss these findings and place them in a broader framework on how cellular hormone signalling regulates root growth plasticity in response to environmental cues.

Rescooped by tianxing84 from Plant-microbe interaction
Scoop.it!

Pseudomonas syringae type III effector AvrRpt2 promotes pathogen virulence via stimulating Arabidopsis Aux/IAA protein turnover

Pseudomonas syringae type III effector AvrRpt2 promotes pathogen virulence via stimulating Arabidopsis Aux/IAA protein turnover | Salicylic Acid | Scoop.it

To accomplish successful infection, pathogens deploy complex strategies to interfere with host defense systems and subterfuge host physiology to favor pathogen survival and multiplication. Modulation of plant auxin physiology and signaling is emerging as a common virulence strategy for phytobacteria to cause diseases. However, the underlying mechanisms remain largely elusive. We have previously shown that the Pseudomonas syringae type III effector AvrRpt2 alters Arabidopsis auxin physiology. Here we report that AvrRpt2 promotes auxin response by stimulating the turnover of Aux/IAA proteins, the key negative regulators in auxin signaling. AvrRpt2 acts additively with auxin to stimulate Aux/IAA turnover, suggesting distinct, yet proteasome-dependent mechanisms operated by AvrRpt2 and auxin to control Aux/IAA stability. The cysteine protease activity is required for AvrRpt2-stimulated auxin signaling and Aux/IAA degradation. Importantly, the transgenic plants expressing the dominant axr2-1 mutation recalcitrant to AvrRpt2-mediated degradation ameliorated virulence functions of AvrRpt2, but did not alter the avirulent function mediated by the corresponding RPS2 resistance protein. Thus, promoting auxin response via modulating the stability of key transcription repressors Aux/IAA is a mechanism used by bacterial type III effector AvrRpt2 to promote pathogenicity.


Via Suayib Üstün
more...
Suayib Üstün's curator insight, May 1, 2013 8:59 AM

I wonder whether Axr2 is a direct target of AvrRpt2? Or is the impaired turnover of Axr2 that is dependent on the cysteine protease activity of AvrRpt2 just an indirect effect?

Rescooped by tianxing84 from of Plants & Bacteria (and sometimes other fellows too)
Scoop.it!

Plant Physiology: Pseudomonas syringae type III effector AvrRpt2 promotes pathogen virulence via stimulating Arabidopsis Aux/IAA protein turnover (2013)

Plant Physiology: Pseudomonas syringae type III effector AvrRpt2 promotes pathogen virulence via stimulating Arabidopsis Aux/IAA protein turnover (2013) | Salicylic Acid | Scoop.it

To accomplish successful infection, pathogens deploy complex strategies to interfere with host defense systems and subterfuge host physiology to favor pathogen survival and multiplication. Modulation of plant auxin physiology and signaling is emerging as a common virulence strategy for phytobacteria to cause diseases. However, the underlying mechanisms remain largely elusive. We have previously shown that the Pseudomonas syringae type III effector AvrRpt2 alters Arabidopsis auxin physiology. Here we report that AvrRpt2 promotes auxin response by stimulating the turnover of Aux/IAA proteins, the key negative regulators in auxin signaling. AvrRpt2 acts additively with auxin to stimulate Aux/IAA turnover, suggesting distinct, yet proteasome-dependent mechanisms operated by AvrRpt2 and auxin to control Aux/IAA stability. The cysteine protease activity is required for AvrRpt2-stimulated auxin signaling and Aux/IAA degradation. Importantly, the transgenic plants expressing the dominant axr2-1 mutation recalcitrant to AvrRpt2-mediated degradation ameliorated virulence functions of AvrRpt2, but did not alter the avirulent function mediated by the corresponding RPS2 resistance protein. Thus, promoting auxin response via modulating the stability of key transcription repressors Aux/IAA is a mechanism used by bacterial type III effector AvrRpt2 to promote pathogenicity.


Via Kamoun Lab @ TSL, Freddy Monteiro
more...
Dinesh Dhurvas's curator insight, March 15, 2014 6:25 PM

Interestingly plant pathogen protein controls Aux/IAA turnover in plants..!

Rescooped by tianxing84 from Plant-microbe interaction
Scoop.it!

Top5 Research Articles of 2012

Top5 Research Articles of 2012 | Salicylic Acid | Scoop.it

2012 is almost over now and I would like to highlight my Top 5 research articles of 2012, which were really inspiring for our own research:

 

 

 

 

 

"Tomato TFT1 Is Required for PAMP-Triggered Immunity and Mutations that Prevent T3S Effector XopN from Binding to TFT1 Attenuate Xanthomonas Virulence"

 

by Kyle W. Taylor , Jung-Gun Kim , Xue B. Su, Chris D. Aakre, Julie A. Roden, Christopher M. Adams, Mary Beth Mudgett

 

http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002768

 

 

"RPN1a, a 26S proteasome subunit, is required for innate immunity in Arabidopsis"

 

by Chunpeng Yao,Yingying Wu,Haozhen Nie, Dingzhong Tang

 

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-313X.2012.05048.x/abstract;jsessionid=F9F0853B8F1EF05907031DFED65A88B2.d03t03

 

 

"NPR3 and NPR4 are receptors for the immune signal salicylic acid in plants"

 

by Zheng Qing Fu, Shunping Yan, Abdelaty Saleh, Wei Wang, James Ruble,      Nodoka Oka, Rajinikanth Mohan, Steven H. Spoel, Yasuomi Tada, Ning Zheng   & Xinnian Dong

 

http://www.nature.com/nature/journal/v486/n7402/full/nature11162.html

 

 

"A Xanthomonas uridine 5′-monophosphate transferase inhibits plant immune kinases"

 

by Feng Feng, Fan Yang, Wei Rong, Xiaogang Wu, Jie Zhang, She Chen, Chaozu He & Jian-Min Zhou

 

http://www.nature.com/nature/journal/v485/n7396/abs/nature10962.html

 

 

"A Bacterial Acetyltransferase Destroys Plant Microtubule Networks and Blocks Secretion"

 

by Amy Huei-Yi Lee, Brenden Hurley, Corinna Felsensteiner, Carmen Yea, Wenzislava Ckurshumova, Verena Bartetzko, Pauline W. Wang, Van Quach, Jennifer D. Lewis, Yulu C. Liu, Frederik Börnke, Stephane Angers, Andrew Wilde, David S. Guttman, Darrell Desveaux

 

http://www.plospathogens.org/article/info%3Adoi%2F10.1371%2Fjournal.ppat.1002523

 

 


Via Suayib Üstün
more...
No comment yet.
Rescooped by tianxing84 from Plants and Microbes
Scoop.it!

New Phytologist: Phylogenetic and experimental evidence for host-specialized cryptic species in a biotrophic oomycete (2012)

New Phytologist: Phylogenetic and experimental evidence for host-specialized cryptic species in a biotrophic oomycete (2012) | Salicylic Acid | Scoop.it

Assortative mating resulting from host plant specialization has been proposed to facilitate rapid ecological divergence in biotrophic plant pathogens. Downy mildews, a major group of biotrophic oomycetes, are prime candidates for testing speciation by host plant specialization.


Here, we combined a phylogenetic and morphological approach with cross-pathogenicity tests to investigate host plant specialization and host range expansion in grapevine downy mildew. This destructive disease is caused by Plasmopara viticola, an oomycete endemic to North America on wild species and cultivated grapevines.


Multiple genealogies and sporangia morphology provide evidence that P. viticola is a complex of four cryptic species, each associated with different host plants. Cross-inoculation experiments showed complete host plant specialization on Parthenocissus quinquefolia and on Vitis riparia, whereas cryptic species found on V. aestivalis, V. labrusca and V. vinifera were revealed to be less specific. We reconstructed the recent host range expansion of P. viticola from wild to cultivated grapevines, and showed that it was accompanied by an increase in aggressiveness of the pathogen.


This case study on grapevine downy mildew illustrates how biotrophic plant pathogens can diversify by host plant specialization and emerge in agrosystems by shifting to cultivated hosts. These results might have important implications for viticulture, including breeding for resistance and disease management.


Via Kamoun Lab @ TSL
more...
No comment yet.
Rescooped by tianxing84 from plant developments
Scoop.it!

Enhanced drought and heat stress tolerance of tobacco plants with ectopically enhanced cytokinin oxidase/dehydrogenase gene expression

Enhanced drought and heat stress tolerance of tobacco plants with ectopically enhanced cytokinin oxidase/dehydrogenase gene expression | Salicylic Acid | Scoop.it

Via PMG
more...
PMG's curator insight, July 2, 2013 10:50 PM

WRKY6:CKX1 plants exhibited high CKX activity in the roots under control conditions. Under stress, the activity of the WRKY6 promoter was down-regulated and the concomitantly reduced cytokinin degradation coincided with raised bioactive cytokinin levels during the early phase of the stress response, which might contribute to enhanced stress tolerance of this genotype. Constitutive expression of CKX1 resulted in an enlarged root system, a stunted, dwarf shoot phenotype, and a low basal level of expression of the dehydration marker gene ERD10B. The high drought tolerance of this genotype was associated with a relatively moderate drop in leaf water potential and a significant decrease in leaf osmotic potential. Basal expression of the proline biosynthetic gene P5CSA was raised. Both wild-type and WRKY6:CKX1 plants responded to heat stress by transient elevation of stomatal conductance, which correlated with an enhanced abscisic acid catabolism. 35S:CKX1 transgenic plants exhibited a small and delayed stomatal response. Nevertheless, they maintained a lower leaf temperature than the other genotypes. Heat shock applied to drought-stressed plants exaggerated the negative stress effects, probably due to the additional water loss caused by a transient stimulation of transpiration. The results indicate that modulation of cytokinin levels may positively affect plant responses to abiotic stress through a variety of physiological mechanisms.

Rescooped by tianxing84 from Plant-microbe interaction
Scoop.it!

Salicylic acid interferes with clathrin-mediated endocytic protein trafficking

Salicylic acid interferes with clathrin-mediated endocytic protein trafficking | Salicylic Acid | Scoop.it

Removal of cargos from the cell surface via endocytosis is an efficient mechanism to regulate activities of plasma membrane (PM)-resident proteins, such as receptors or transporters. Salicylic acid (SA) is an important plant hormone that is traditionally associated with pathogen defense. Here, we describe an unanticipated effect of SA on subcellular endocytic cycling of proteins. Both exogenous treatments and endogenously enhanced SA levels repressed endocytosis of different PM proteins. The SA effect on endocytosis did not involve transcription or known components of the SA signaling pathway for transcriptional regulation. SA likely targets an endocytic mechanism that involves the coat protein clathrin, because SA interfered with the clathrin incidence at the PM and clathrin-deficient mutants were less sensitive to the impact of SA on the auxin distribution and root bending during the gravitropic response. By contrast, SA did not affect the ligand-induced endocytosis of the FLAGELLIN SENSING2 (FLS2) receptor during pathogen responses. Our data suggest that the established SA impact on transcription in plant immunity and the nontranscriptional effect of SA on clathrin-mediated endocytosis are independent mechanisms by which SA regulates distinct aspects of plant physiology.


Via Guogen Yang, Suayib Üstün
more...
No comment yet.
Rescooped by tianxing84 from Plant-Microbe Interaction
Scoop.it!

Salicylic Acid Regulates Plasmodesmata Closure during Innate Immune Responses in Arabidopsis

Salicylic Acid Regulates Plasmodesmata Closure during Innate Immune Responses in Arabidopsis | Salicylic Acid | Scoop.it

In plants, mounting an effective innate immune strategy against microbial pathogens involves triggering local cell death within
infected cells as well as boosting the immunity of the uninfected neighboring and systemically located cells. Although not
much is known about this, it is evident that well-coordinated cell–cell signaling is critical in this process to confine infection to
local tissue while allowing for the spread of systemic immune signals throughout the whole plant. In support of this notion,
direct cell-to-cell communication was recently found to play a crucial role in plant defense. Here, we provide experimental
evidence that salicylic acid (SA) is a critical hormonal signal that regulates cell-to-cell permeability during innate immune
responses elicited by virulent bacterial infection in Arabidopsis thaliana. We show that direct exogenous application of SA or
bacterial infection suppresses cell–cell coupling and that SA pathway mutants are impaired in this response. The SA- or
infection-induced suppression of cell–cell coupling requires an ENHANCED DESEASE RESISTANCE1– and NONEXPRESSOR
OF PATHOGENESIS-RELATED GENES1–dependent SA pathway in conjunction with the regulator of plasmodesmal gating
PLASMODESMATA-LOCATED PROTEIN5. We discuss a model wherein the SA signaling pathway and plasmodesmatamediated cell-to-cell communication converge under an intricate regulatory loop.


Via Suayib Üstün, Guogen Yang
more...
No comment yet.
Rescooped by tianxing84 from Plant-Microbe Interaction
Scoop.it!

New Phytol.: Emerging role for RNA-based regulation in plant immunity (2012)

New Phytol.: Emerging role for RNA-based regulation in plant immunity (2012) | Salicylic Acid | Scoop.it

Infection by phytopathogenic bacteria triggers massive changes in plant gene expression, which are thought to be mostly a result of transcriptional reprogramming. However, evidence is accumulating that plants additionally use post-transcriptional regulation of immune-responsive mRNAsas a strategic weapon to shape the defense-related transcriptome. Cellular RNA-binding
proteins regulate RNA stability, splicing or mRNA export of immune-response transcripts. In particular, mutants defective in alternative splicing of resistance genes exhibit compromised
disease resistance. Furthermore, detection of bacterial pathogens induces the differential
expression of small non-coding RNAs including microRNAs that impact the host defense transcriptome. Phytopathogenic bacteria in turn have evolved effector proteins to inhibit
biogenesis and/or activity of cellular microRNAs. WhereasRNAsilencing has longbeenknownas
an antiviral defense response, recent findings also reveal a major role of this process in
antibacterial defense. Here we review the function of RNA-binding proteins and small RNAdirected post-transcriptional regulation in antibacterial defense.We mainly focus on studies that used the model system Arabidopsis thaliana and also discuss selected examples from other plants.

 

Dorothee Staiger, Christin Korneli, Martina Lummer and Lionel Navarro


Via Nicolas Denancé, Guogen Yang
more...
No comment yet.
Rescooped by tianxing84 from Trends in MPMI
Scoop.it!

PLOS ONE: Cauliflower mosaic virus Protein P6 Inhibits Signaling Responses to Salicylic Acid and Regulates Innate Immunity

PLOS ONE: Cauliflower mosaic virus Protein P6 Inhibits Signaling Responses to Salicylic Acid and Regulates Innate Immunity | Salicylic Acid | Scoop.it

Cauliflower mosaic virus (CaMV) encodes a multifunctional protein P6 that is required for translation of the 35S RNA and also acts as a suppressor of RNA silencing. Here we demonstrate that P6 additionally acts as a pathogenicity effector of an unique and novel type, modifying NPR1 (a key regulator of salicylic acid (SA)- and jasmonic acid (JA)-dependent signaling) and inhibiting SA-dependent defence responses We find that that transgene-mediated expression of P6 in Arabidopsis and transient expression in Nicotiana benthamiana has profound effects on defence signaling, suppressing expression of representative SA-responsive genes and increasing expression of representative JA-responsive genes. Relative to wild-type Arabidopsis P6-expressing transgenics had greatly reduced expression of PR-1 following SA-treatment, infection by CaMV or inoculation with an avirulent bacterial pathogen Pseudomonas syringae pv tomato (Pst). Similarly transient expression in Nicotiana benthamiana of P6 (including a mutant form defective in translational transactivation activity) suppressed PR-1a transcript accumulation in response to Agrobacterium infiltration and following SA-treatment. As well as suppressing the expression of representative SA-regulated genes, P6-transgenic Arabidopsis showed greatly enhanced susceptibility to both virulent and avirulent Pst (titres elevated 10 to 30-fold compared to non-transgenic controls) but reduced susceptibility to the necrotrophic fungus Botrytis cinerea. Necrosis following SA-treatment or inoculation with avirulent Pst was reduced and delayed in P6-transgenics. NPR1 an important regulator of SA/JA crosstalk, was more highly expressed in the presence of P6 and introduction of the P6 transgene into a transgenic line expressing an NPR1:GFP fusion resulted in greatly increased fluorescence in nuclei even in the absence of SA. Thus in the presence of P6 an inactive form of NPR1 is mislocalized in the nucleus even in uninduced plants. These results demonstrate that P6 is a new type of pathogenicity effector protein that enhances susceptibility to biotrophic pathogens by suppressing SA- but enhancing JA-signaling responses.


Via Suayib Üstün, CP
more...
No comment yet.