scholarly journals Arabidopsis cell surface LRR immune receptor signaling through the EDS1-PAD4-ADR1 node

Author(s):  
Rory N. Pruitt ◽  
Lisha Zhang ◽  
Svenja C. Saile ◽  
Darya Karelina ◽  
Katja Fröhlich ◽  
...  

AbstractPlants use both cell surface and intracellular immune receptors with leucine rich-repeat (LRRs) to detect pathogens. LRR receptor kinases (LRR-RKs) and LRR receptor-like proteins (LRR-RPs) recognize extracellular microbe-derived molecules to confer pattern-triggered immunity (PTI), while nucleotide-binding LRR (NLR) proteins detect microbial effectors inside the cell to confer effector-triggered immunity (ETI). Despite PTI and ETI signaling being initiated in different compartments, both rely on the transcriptional activation of similar sets of genes, suggesting convergence in signaling upstream of nuclear events. Here we report that two sets of molecules, helper NLRs from the ADR1 (ACTIVATED DISEASE RESISTANCE 1) family as well as lipase-like proteins EDS1 (ENHANCED DISEASE SUSCEPTIBILITY 1) and PAD4 (PHYTOALEXIN DEFICIENT 4), are required not only for ETI, but also for PTI. A further similarity is seen in the evolutionary patterns of some PTI and ETI receptor genes, with both often being highly polymorphic, and with nevertheless distinct roles of LRR-RK and LRR-RP receptors in immunity. We find that the LRR-RK SOBIR1 directly links LRR-RPs with the ADR1 helper NLR as well as EDS1 and PAD4, suggesting the formation of constitutive supramolecular signalosome complexes at the inner side of the plasma membrane. We propose that the EDS1-PAD4-ADR1 node is an essential component and convergence point for immune signaling cascades activated by both surface-resident LRR-RP receptors and intracellular NLR receptors.

2022 ◽  
Vol 12 ◽  
Author(s):  
Md Al Mamun ◽  
Md Tabibul Islam ◽  
Bok-Rye Lee ◽  
Dong-Won Bae ◽  
Tae-Hwan Kim

To characterize cultivar variations in hormonal regulation of the transition between pattern-triggered immunity (PTI) and effector-triggered immunity or susceptibility (ETI or ETS), the responses of resistance (R-) genes, hydrogen peroxide, and proline metabolism in two Brassica napus cultivars to contrasting disease susceptibility (resistant cv. Capitol vs. susceptible cv. Mosa) were interpreted as being linked to those of endogenous hormonal levels and signaling genes based on a time course of disease symptom development. Disease symptoms caused by the Xanthomonas campestris pv. campestris (Xcc) infections were much more developed in cv. Mosa than in cv. Capitol, as shown by an earlier appearance (at 3 days postinoculation [3 DPI]) and larger V-shaped necrosis lesions (at 9–15 DPI) in cv. Mosa. The cultivar variations in the R-genes, hormone status, and proline metabolism were found in two different phases (early [0–3 DPI] and later [9–15 DPI]). In the early phase, Xcc significantly upregulated PTI-related cytoplasmic kinase (Botrytis-induced kinase-1 [BIK1]) expression (+6.3-fold) with salicylic acid (SA) accumulation in cv. Capitol, while relatively less (+2.6-fold) with highly increased jasmonic acid (JA) level in cv. Mosa. The Xcc-responsive proline accumulation in both cultivars was similar to upregulated expression of proline synthesis-related genes (P5CS2 and P5CR). During the later phase in cv. Capitol, Xcc-responsive upregulation of ZAR1 (a coiled-coil-nucleotide binding site-leucine-rich repeat [CC-NB-LRR-type R-gene]) was concomitant with a gradual increase in JA levels without additional proline accumulation. However, in cv. Mosa, upregulation of TAO1 (a toll/interleukin-1 receptor-nucleotide binding site-leucine-rich repeat [TIR-NB-LRR-type R-gene]) was consistent with an increase in SA and abscisic acid (ABA) levels and resulted in an antagonistic depression of JA, which led to a proline accumulation. These results indicate that Xcc-induced BIK1- and ZAR1-mediated JA signaling interactions provide resistance and confirm ETI, whereas BIK1- and TAO1-enhanced SA- and/or ABA-mediated proline accumulation is associated with disease susceptibility (ETS).


Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 303
Author(s):  
Md. Al Mamun ◽  
Md. Tabibul Islam ◽  
Bok-Rye Lee ◽  
Van Hien La ◽  
Dong-Won Bae ◽  
...  

To characterize cultivar variation in resistance gene (R-gene)-mediated calcium signaling and hormonal regulation in effector-triggered immunity (ETI) and disease susceptibility, Xanthomonas campestris pv. campestris (Xcc) was inoculated in two Brassica napus cultivars (cvs. Capitol and Mosa). At 14 days post inoculation (DPI) with Xcc, there was a necrotic lesion in cv. Mosa along with the significant accumulation of H2O2 and malondialdehyde (MDA), whereas no visual symptom was observed in cv. Capitol. The cultivar variations in the R-gene expressions were found in response to Xcc. ZAR1 is a coiled-coil-nucleotide binding site-leucine-rich repeat (CC-NB-LRR)-type R-gene that is significantly induced in cv. Capitol, whereas toll/interleukin-1 receptor-nucleotide binding site-leucine-rich repeat (TIR-NB-LRR)-type R-gene, TAO1, is significantly upregulated in cv. Mosa Xcc-inoculated plants. The defense-related gene’s non-race-specific disease resistance 1 (NDR1) and mitogen-activated protein kinase 6 (MAPK6) were enhanced, whereas calcium-dependent protein kinase (CDPK5) and calcium-sensing protein 60g (CBP60g) were depressed in cv. Capitol Xcc inoculated plants, and opposite results were found in cv. Mosa. The calcium-sensing receptor (CAS), calmodulin (CaM), expression was induced in both the cultivars. However, the CAS induction rate was much higher in cv. Mosa than in cv. Capitol in response to Xcc. The phytohormone salicylic acid (SA) and jasmonic acid (JA) levels were significantly higher in cv. Capitol along with the enhanced SA receptors (NPR3 and NPR4) and JA synthesis and signaling-related gene expression (LOX2, PDF1.2), whereas the JA level was significantly lower in cv. Mosa Xcc inoculated plants. The SA synthesis and signaling-related genes (ICS1, NPR1) and SA were present at higher levels in cv. Mosa; additionally, the SA level present was much higher in the susceptible cultivar (cv. Mosa) than in the resistant cultivar (cv. Capitol) in response to Xcc. These results indicate that ZAR1 mediated the coordinated action of SA and JA synthesis and signaling to confirm ETI, whereas TAO1 enhanced the synthesis of SA through CAS and CBP60g to antagonize JA synthesis and signaling to cause disease susceptibility in the Brassica napus–Xcc pathosystem.


2021 ◽  
Vol 22 (14) ◽  
pp. 7440
Author(s):  
Shraddha K. Dahale ◽  
Daipayan Ghosh ◽  
Kishor D. Ingole ◽  
Anup Chugani ◽  
Sang Hee Kim ◽  
...  

Pseudomonas syringae-secreted HopA1 effectors are important determinants in host range expansion and increased pathogenicity. Their recent acquisitions via horizontal gene transfer in several non-pathogenic Pseudomonas strains worldwide have caused alarming increase in their virulence capabilities. In Arabidopsis thaliana, RESISTANCE TO PSEUDOMONAS SYRINGAE 6 (RPS6) gene confers effector-triggered immunity (ETI) against HopA1pss derived from P. syringae pv. syringae strain 61. Surprisingly, a closely related HopA1pst from the tomato pathovar evades immune detection. These responsive differences in planta between the two HopA1s represents a unique system to study pathogen adaptation skills and host-jumps. However, molecular understanding of HopA1′s contribution to overall virulence remain undeciphered. Here, we show that immune-suppressive functions of HopA1pst are more potent than HopA1pss. In the resistance-compromised ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1) null-mutant, transcriptomic changes associated with HopA1pss-elicited ETI are still induced and carry resemblance to PAMP-triggered immunity (PTI) signatures. Enrichment of HopA1pss interactome identifies proteins with regulatory roles in post-transcriptional and translational processes. With our demonstration here that both HopA1 suppress reporter-gene translations in vitro imply that the above effector-associations with plant target carry inhibitory consequences. Overall, with our results here we unravel possible virulence role(s) of HopA1 in suppressing PTI and provide newer insights into its detection in resistant plants.


2011 ◽  
Vol 24 (1) ◽  
pp. 100-107 ◽  
Author(s):  
Tingting Xiang ◽  
Na Zong ◽  
Jie Zhang ◽  
Jinfeng Chen ◽  
Mingsheng Chen ◽  
...  

Plant cell surface-localized receptor kinases such as FLS2, EFR, and CERK1 play a crucial role in detecting invading pathogenic bacteria. Upon stimulation by bacterium-derived ligands, FLS2 and EFR interact with BAK1, a receptor-like kinase, to activate immune responses. A number of Pseudomonas syringae effector proteins are known to block immune responses mediated by these receptors. Previous reports suggested that both FLS2 and BAK1 could be targeted by the P. syringae effector AvrPto to inhibit plant defenses. Here, we provide new evidence further supporting that FLS2 but not BAK1 is targeted by AvrPto in plants. The AvrPto-FLS2 interaction prevented the phosphorylation of BIK1, a downstream component of the FLS2 pathway.


2009 ◽  
Vol 11 (10) ◽  
pp. 1254-1260 ◽  
Author(s):  
Tae-Wuk Kim ◽  
Shenheng Guan ◽  
Yu Sun ◽  
Zhiping Deng ◽  
Wenqiang Tang ◽  
...  

2020 ◽  
Vol 71 (6) ◽  
pp. 2186-2197 ◽  
Author(s):  
Bruno Pok Man Ngou ◽  
Hee-Kyung Ahn ◽  
Pingtao Ding ◽  
Amey Redkar ◽  
Hannah Brown ◽  
...  

Abstract Plant nucleotide-binding domain, leucine-rich repeat receptor (NLR) proteins play important roles in recognition of pathogen-derived effectors. However, the mechanism by which plant NLRs activate immunity is still largely unknown. The paired Arabidopsis NLRs RRS1-R and RPS4, that confer recognition of bacterial effectors AvrRps4 and PopP2, are well studied, but how the RRS1/RPS4 complex activates early immediate downstream responses upon effector detection is still poorly understood. To study RRS1/RPS4 responses without the influence of cell surface receptor immune pathways, we generated an Arabidopsis line with inducible expression of the effector AvrRps4. Induction does not lead to hypersensitive cell death response (HR) but can induce electrolyte leakage, which often correlates with plant cell death. Activation of RRS1 and RPS4 without pathogens cannot activate mitogen-associated protein kinase cascades, but still activates up-regulation of defence genes, and therefore resistance against bacteria.


Blood ◽  
1997 ◽  
Vol 90 (9) ◽  
pp. 3345-3355 ◽  
Author(s):  
Yury Monczak ◽  
Michel Trudel ◽  
William W. Lamph ◽  
Wilson H. Miller

Abstract Retinoic acid (RA) induces differentiation, followed by apoptosis in acute promyelocytic leukemia (APL) cells, both in vitro and in patients. One problem in understanding these mechanisms is to distinguish molecular events leading to differentiation from those leading to apoptosis. We have identified a leukemic cell line, PLB-985, where RA directly induces apoptosis with no morphologic, genetic, or cell-surface marker evidence of differentiation. These cells differentiate following dimethyl sulfoxide (DMSO), but not RA, treatment. Two-color flow cytometry showed no alteration of the cell cycle after RA treatment, and cell-surface marker analysis of CD11a, CD11b, and CD13 showed no modulation typical of differentiating cells. RNA expression of myeloblastin and transglutaminase, genes regulated by RA-induced differentiation in NB4 cells, was unchanged by RA treatment. Instead, RA induced apoptosis, as shown by typical apoptotic morphological features, genomic DNA laddering, and positive labeling in the TUNEL assay. We found that induction of apoptosis in this model requires a different pattern of retinoid receptor binding and transcriptional activation than is seen in APL cells. As previously described, treatment with retinoid receptor-selective ligands showed that stimulation of RAR alone is sufficient to induce differentiation and apoptosis in NB4 cells, and that stimulation of RXR has no effect on the parameters analyzed. In PLB-985 cells, on the other hand, apoptosis was induced only upon costimulation of both RAR and RXR. Stimulation of either receptor alone had no effect on the cells. Consistent with these findings, bcl-2 RNA and protein levels were downregulated after stimulation of both RAR and RXR, but not with an RAR-specific ligand alone, as in NB4 cells. The expression of several other bcl-2 family members (bcl-X, ich-1, bax, bag, and bak ) and retinoid receptors (RARα, RXRα, and RXRβ) was not affected by treatment with RAR- and/or RXR-activating retinoids; RARβ RNA was undetectable before and after retinoid treatment. Thus, our cell model provides a useful tool in determining the genetic events mediating apoptosis as a response to RA, unobscured by events implicated in differentiation.


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