scholarly journals Extracellular pyridine nucleotides trigger plant systemic immunity through a lectin receptor kinase/BAK1 complex

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Chenggang Wang ◽  
Xiaoen Huang ◽  
Qi Li ◽  
Yanping Zhang ◽  
Jian-Liang Li ◽  
...  

Abstract Systemic acquired resistance (SAR) is a long-lasting broad-spectrum plant immunity induced by mobile signals produced in the local leaves where the initial infection occurs. Although multiple structurally unrelated signals have been proposed, the mechanisms responsible for perception of these signals in the systemic leaves are unknown. Here, we show that exogenously applied nicotinamide adenine dinucleotide (NAD+) moves systemically and induces systemic immunity. We demonstrate that the lectin receptor kinase (LecRK), LecRK-VI.2, is a potential receptor for extracellular NAD+ (eNAD+) and NAD+ phosphate (eNADP+) and plays a central role in biological induction of SAR. LecRK-VI.2 constitutively associates with BRASSINOSTEROID INSENSITIVE1-ASSOCIATED KINASE1 (BAK1) in vivo. Furthermore, BAK1 and its homolog BAK1-LIKE1 are required for eNAD(P)+ signaling and SAR, and the kinase activities of LecR-VI.2 and BAK1 are indispensable to their function in SAR. Our results indicate that eNAD+ is a putative mobile signal, which triggers SAR through its receptor complex LecRK-VI.2/BAK1 in Arabidopsis thaliana.

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Chenggang Wang ◽  
Mingqi Zhou ◽  
Xudong Zhang ◽  
Jin Yao ◽  
Yanping Zhang ◽  
...  

Nicotinamide adenine dinucleotide (NAD+) participates in intracellular and extracellular signaling events unrelated to metabolism. In animals, purinergic receptors are required for extracellular NAD+ (eNAD+) to evoke biological responses, indicating that eNAD+ may be sensed by cell-surface receptors. However, the identity of eNAD+-binding receptors still remains elusive. Here, we identify a lectin receptor kinase (LecRK), LecRK-I.8, as a potential eNAD+ receptor in Arabidopsis. The extracellular lectin domain of LecRK-I.8 binds NAD+ with a dissociation constant of 436.5 ± 104.8 nM, although much higher concentrations are needed to trigger in vivo responses. Mutations in LecRK-I.8 inhibit NAD+-induced immune responses, whereas overexpression of LecRK-I.8 enhances the Arabidopsis response to NAD+. Furthermore, LecRK-I.8 is required for basal resistance against bacterial pathogens, substantiating a role for eNAD+ in plant immunity. Our results demonstrate that lectin receptors can potentially function as eNAD+-binding receptors and provide direct evidence for eNAD+ being an endogenous signaling molecule in plants.


2011 ◽  
Vol 38 (10) ◽  
pp. 747
Author(s):  
Alireza Seifi

About 50 years ago, it was reported that pathogen-infected plants are less susceptible to a broad spectrum of the subsequent pathogen attacks. This form of induced resistance, which resembles the immunisation in mammalian cells, is called systemic acquired resistance (SAR). In the last 10 years, plant molecular biology has been revolutionised by the discovery of RNA silencing, which is also a systemic phenomenon and also contributes to plant immunity. Here, I review these two systemic phenomena in a comparative way to highlight the possibility that systemic silencing contributes to systemic immunity. This potential contribution could be in the process of gene expression reprogramming, which is needed for SAR induction, and/or in SAR signal complex, and/or in establishing SAR in remote tissues and forming priming status.


Genetics ◽  
2002 ◽  
Vol 160 (4) ◽  
pp. 1661-1671
Author(s):  
Klaus Maleck ◽  
Urs Neuenschwander ◽  
Rebecca M Cade ◽  
Robert A Dietrich ◽  
Jeffery L Dangl ◽  
...  

Abstract To identify Arabidopsis mutants that constitutively express systemic acquired resistance (SAR), we constructed reporter lines expressing the firefly luciferase gene under the control of the SAR-inducible PR-1 promoter (PR-1/luc). After EMS mutagenesis of a well-characterized transgenic line, we screened 250,000 M2 plants for constitutive expression of the reporter gene in vivo. From a mutant collection containing several hundred putative mutants, we concentrated on 16 mutants lacking spontaneous hypersensitive response (HR) cell death. We mapped 4 of these constitutive immunity (cim) mutants to chromosome arms. Constitutive expression of disease resistance was established by analyzing responses to virulent Peronospora parasitica and Pseudomonas syringae strains, by RNA blot analysis for endogenous marker genes, and by determination of salicylic acid levels in the mutants. The variety of the cim phenotypes allowed us to define distinct steps in both the canonical SAR signaling pathway and a separate pathway for resistance to Erysiphe cichoracearum, active in only a subset of the mutants.


2019 ◽  
Vol 20 (5) ◽  
pp. 1211 ◽  
Author(s):  
Jingjing Zhang ◽  
Ziyu Ren ◽  
Yuqing Zhou ◽  
Zheng Ma ◽  
Yanqin Ma ◽  
...  

The circadian clock in plants synchronizes biological processes that display cyclic 24-h oscillation based on metabolic and physiological reactions. This clock is a precise timekeeping system, that helps anticipate diurnal changes; e.g., expression levels of clock-related genes move in synchrony with changes in pathogen infection and help prepare appropriate defense responses in advance. Salicylic acid (SA) is a plant hormone and immune signal involved in systemic acquired resistance (SAR)-mediated defense responses. SA signaling induces cellular redox changes, and degradation and rhythmic nuclear translocation of the non-expresser of PR genes 1 (NPR1) protein. Recent studies demonstrate the ability of the circadian clock to predict various potential attackers, and of redox signaling to determine appropriate defense against pathogen infection. Interaction of the circadian clock with redox rhythm promotes the balance between immunity and growth. We review here a variety of recent evidence for the intricate relationship between circadian clock and plant immune response, with a focus on the roles of redox rhythm and NPR1 in the circadian clock and plant immunity.


Author(s):  
Lennart Mohnike ◽  
Dmitrij Rekhter ◽  
Weijie Huang ◽  
Kirstin Feussner ◽  
Hainan Tian ◽  
...  

AbstractThe trade-off between growth and defense is a critical aspect of plant immunity. Therefore, plant immune response needs to be tightly regulated. The hormone regulating plant defense against biotrophic pathogens is salicylic acid (SA). Recently, N-hydroxy-pipecolic acid (NHP) was identified as second regulator for plant innate immunity and systemic acquired resistance. Although the biosynthetic pathway leading to NHP formation has already been identified, the route how NHP is further metabolized was unclear. Here, we present UGT76B1 as a UDP-dependent glycosyltransferase that modifies NHP by catalyzing the formation of 1-O-glucosyl-pipecolic acid (NHP-OGlc). Analysis of T-DNA and CRISPR knock-out mutant lines of UGT76B1 by targeted and non-targeted UHPLC-HRMS underlined NHP and SA as endogenous substrates of this enzyme in response to Pseudomonas infection and UV treatment. UGT76B1 shows similar KM for NHP and SA. ugt76b1 mutant plants have a dwarf phenotype and a constitutive defense response which can be suppressed by loss of function of the NHP biosynthetic enzyme FMO1. This suggests that elevated accumulation of NHP contributes to the enhanced disease resistance in ugt76b1. Externally applied NHP can move to distal tissue in ugt76b1 mutant plants. Although glycosylation is not required for the long distance movement of NHP during systemic acquired resistance, it is crucial to balance growth and defense.


Author(s):  
Thea Magrone ◽  
Manrico Magrone ◽  
Matteo Antonio Russo ◽  
Emilio Jirillo

Background: Despite the evidence that plants do not possess sessile cells, they are able to mount a vigorous immune response against invaders or under stressful conditions. Mechanisms of action: Plants are endowed with pattern recognition receptors (PPRs) which perceive damage-associated molecular patterns and microbe-associated molecular patterns or pathogen-associated molecular patterns (PAMPs), respectively. PPR activation leads to either the initiation of PAMP-triggered immunity (PTI) (early response) or the effectortriggered immunity (ETI). Both PTI and ETI contribute to plant systemic acquired resistance as also an expression of immunological memory or trained immunity. Plant immune receptors: PTI is initiated by activation of both receptor-like kinases and receptor-like proteins, while ETI depends on nucleotide-binding leucine-rich-repeat protein receptors for microbe recognition. Peptides involved in plant defenses: Plant chloroplasts contribute to both PTI and ETI through production of peptides which act as hormones or phytocytokines. Salicylic acid, jasmonic acid and ethylene are the major compounds involved in plant defense. Specific aims: The interaction between plant receptors and/or their products and bacterial components will be discussed. Also emphasis will be placed on plant microbiome for its contribution to plant immune response. Finally, the mutual interplay between insects and plants will also be illustrated. Conclusion: A better knowledge on plant immunity may pave the way for the exploitation of plant derivatives in the field of agriculture and medicine, as well.


2021 ◽  
Vol 72 (1) ◽  
Author(s):  
Yujun Peng ◽  
Jianfei Yang ◽  
Xin Li ◽  
Yuelin Zhang

Salicylic acid (SA) is an essential plant defense hormone that promotes immunity against biotrophic and semibiotrophic pathogens. It plays crucial roles in basal defense and the amplification of local immune responses, as well as the establishment of systemic acquired resistance. During the past three decades, immense progress has been made in understanding the biosynthesis, homeostasis, perception, and functions of SA. This review summarizes the current knowledge regarding SA in plant immunity and other biological processes. We highlight recent breakthroughs that substantially advanced our understanding of how SA is biosynthesized from isochorismate, how it is perceived, and how SA receptors regulate different aspects of plant immunity. Some key questions in SA biosynthesis and signaling, such as how SA is produced via another intermediate benzoic acid and how SA affects the activities of its receptors in the transcriptional regulation of defense genes, remain to be addressed. Expected final online publication date for the Annual Review of Plant Biology, Volume 72 is May 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


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