Makes caterpillars floppy-like effector-containing MARTX toxins require host ADP-ribosylation factor (ARF) proteins for systemic pathogenicity

Lee, Youngjin,Kim, Byoung Sik,Choi, Sanghyeon,Lee, Eun-Young,Park, Shinhye,Hwang, Jungwon,Kwon, Yumi,Hyun, Jaekyung,Lee, Cheolju,Kim, Jihyun F.,Eom, Soo Hyun,Kim, Myung Hee National Academy of Sciences 2019 Proceedings of the National Academy of Sciences Vol.116 No.36

<P><B>Significance</B></P><P>MARTX toxins present across multiple bacterial genera are primary virulence factors that facilitate initial colonization, dissemination, and lethality in a wide range of hosts, including humans. Upon entry into host cells, the toxins undergo a processing event to release their disease-related modularly structured effector domains. However, the mechanisms underlying processing and activation of diverse effector domains within the toxins remain unclear. Here, we use biochemical and structural biological approaches, in combination with cellular microbiological experiments, to demonstrate how Makes caterpillars floppy-like effector (MCF) or its homolog-containing MARTX toxins process effector modules and fully activate effectors. MCF-containing toxins target ADP-ribosylation factor proteins ubiquitously expressed in cells to activate and disseminate effectors across subcellular compartments simultaneously, eventually leading to systemic pathogenicity.</P><P>Upon invading target cells, multifunctional autoprocessing repeats-in-toxin (MARTX) toxins secreted by bacterial pathogens release their disease-related modularly structured effector domains. However, it is unclear how a diverse repertoire of effector domains within these toxins are processed and activated. Here, we report that Makes caterpillars floppy-like effector (MCF)-containing MARTX toxins require ubiquitous ADP-ribosylation factor (ARF) proteins for processing and activation of intermediate effector modules, which localize in different subcellular compartments following limited processing of holo effector modules by the internal cysteine protease. Effector domains structured tandemly with MCF in intermediate modules become disengaged and fully activated by MCF, which aggressively interacts with ARF proteins present at the same location as intermediate modules and is converted allosterically into a catalytically competent protease. MCF-mediated effector processing leads ultimately to severe virulence in mice via an MCF-mediated ARF switching mechanism across subcellular compartments. This work provides insight into how bacteria take advantage of host systems to induce systemic pathogenicity.</P>

Multiple recognition of RXLR effectors is associated with nonhost resistance of pepper against <i>Phytophthora infestans</i>

Lee, Hyun-Ah,Kim, Shin-Young,Oh, Sang-Keun,Yeom, Seon-In,Kim, Saet-Byul,Kim, Myung-Shin,Kamoun, Sophien,Choi, Doil Blackwell Publishing Ltd 2014 The New phytologist Vol.203 No.3

<P><P>Nonhost resistance (NHR) is a plant immune response to resist most pathogens. The molecular basis of NHR is poorly understood, but recognition of pathogen effectors by immune receptors, a response known as effector-triggered immunity, has been proposed as a component of NHR.</P><P>We performed transient expression of 54 <I>Phytophthora infestans</I>RXLR effectors in pepper (<I>Capsicum annuum</I>) accessions. We used optimized heterologous expression methods and analyzed the inheritance of effector-induced cell death in an F<SUB>2</SUB> population derived from a cross between two pepper accessions.</P><P>Pepper showed a localized cell death response upon inoculation with <I>P. infestans</I>, suggesting that recognition of effectors may contribute to NHR in this system. Pepper accessions recognized as many as 36 effectors. Among the effectors, PexRD8 and Avrblb2 induced cell death in a broad range of pepper accessions. Segregation of effector-induced cell death in an F<SUB>2</SUB> population derived from a cross between two pepper accessions fit 15 : 1, 9 : 7 or 3 : 1 ratios, depending on the effector.</P><P>Our genetic data suggest that a single or two independent/complementary dominant genes are involved in the recognition of RXLR effectors. Multiple loci recognizing a series of effectors may underpin NHR of pepper to <I>P. infestans</I> and confer resistance durability.</P></P>

Shaping the understanding of saliva-derived effectors towards aphid colony proliferation in host plant

Hossain Ali Mondal 한국식물학회 2017 Journal of Plant Biology Vol.60 No.2

‘Effectors’ are proteins and/or small molecules that originated from aphid saliva gland and its secretion is initiated due to interaction between host and insect. The effectors have the ability to manipulate the host cell structure as well as function similar to pathogen’s effectors. Like pathogen’s effectors, aphid effectors suppress the hosts’ defense responses as well as hosts’ defense induction or both. In the susceptible interaction with the host, aphid effectors alter plant processes that contribute to the establishment of compatibility that promotes aphid proliferation. In the susceptible reaction with the host, aphid effectors contribute to the successful salivation and sustainability of the sieve element sap ingestion that have promoting role in more aphid proliferation. In the resistant interaction with the host, aphid effectors are recognized by the typical plant receptors and elicit the induction the effective defense response. As a result, aphid proliferation is reduced due to reduced compatibility establishment in the resistant host. This review focuses on the exciting progress in aphid effector biology that insights new perspective in the molecular basis of plant–aphid interactions.

Proteomic Analysis of Shigella Virulence Effectors Secreted under Different Conditions

( Xingming Liu ),( Lilan Lu ),( Xinrui Liu ),( Xiankai Liu ),( Chao Pan ),( Erling Feng ),( Dongshu Wang ),( Chang Niu ),( Li Zhu ),( Hengliang Wang ) 한국미생물생명공학회 2017 Journal of Microbiology and Biotechnology Vol.27 No.1

A series of novel effector molecules secreted by the type three secretion system (T3SS) of Shigella spp. have been reported in recent years. In this study, a proteomic approach was applied to study T3SS effectors systematically. First, proteins secreted by the S. flexneri wildtype strain after Congo Red induction were separated and identified using two-dimensional electrophoresis to display the relative abundance of all kinds of early effectors for the first time. Then, a gene deletion mutant of known virulence repressor (OspD1) and a gene overexpressed mutant of two known virulence activators (MxiE and IpgC) were constructed and analyzed to discover potential late effectors. Furthermore, the supernatant proteins of gene deletion mutants of two known translocators (IpaB and IpaD), which would constantly secrete effectors, were also analyzed. Among all of the secreted proteins identified in our study, IpaH1.4, IpaH_5, and IpaH_7 have not been reported before. These proteomics data of the secreted effectors will be valuable to understand the pathogenesis of S. flexneri.

The F-box Containing Bacterial Effector RipG6 Destabilizes a Receptor-Like Cytoplasmic Kinase Involved in Plant Immune Signaling

Hyelim Jeon,Jihyun Choi,Nawon Song,Wanhui Kim,Cécile Segonzac 한국식물병리학회 2026 The Plant Pathology Journal Vol.42 No.3

Bacterial pathogens employ a large array of type IIIsecreted effectors to manipulate host cell immunity and metabolism. Ralstonia solanacearum species complex, the causal agent of bacterial wilt disease in numerous plant hosts, deploy a conserved subset of RipG effectors containing leucine-rich repeats and an F-box motif that collectively contribute to virulence and host specificity. RipG effectors are proposed to hijack the eukaryotic ubiquitin-proteasome machinery through the recruitment of substrates to host Skp1-cullin-F-box ubiquitinligase complexes via RipG F-box/host Skp1 adaptor interactions. However, only few host proteins have been reported to interact with RipG effectors. Here, using a surrogate type III delivery and a heterologous expression systems, we show that RipG6 can suppress plant pattern-triggered immunity in an F-box-dependent manner. We further identified a tomato receptor-like cytoplasmic kinase (SlRLCK-VIII-6) as an interactor of RipG6 in yeast and plant cells. SlRLCK-VIII-6 stability was reduced when co-expressed with RipG6 but not with the RipG6 variant lacking the F-box motif. Lastly, we provide evidence that Nicotiana benthamiana and Arabidopsis thaliana homologs of SlRLCK-VIII-6 can act as positive regulators of plant immune signaling. Together, our work supports a model where RipG6 destabilizes RLCK-VIII-6 possibly via its recruitment in a host ubiquitin-ligase complex in order to suppress plant immunity. Further research into RLCK-VIII role will enhance our understanding of the manipulation of plant immunity signaling by pathogen effectors.

An RXLR effector disrupts vesicle trafficking at ER-Golgi interface for Phytophthora capsici pathogenicity

Jihyun Kim,Jesse Kaleku,Haeun Kim,Minji Kang,Hui Jeong Kang,Jongchan Woo,Hongshi Jin,Seungmee Jung,Cecile Segonzac,Eunsook Park,Doil Choi Korean Society for Molecular and Cellular Biology 2024 Molecules and cells Vol.47 No.12

Phytophthora species, an oomycete plant pathogen, secrete effectors into plant cells throughout their life cycle for manipulating host immunity to achieve successful colonization. However, the molecular mechanisms underlying effector-triggered necrotic cell death remain elusive. In this study, we identified an RXLR (amino acid residue; Arginine-Any amino acid-Leucine-Arginine motif) effector (Pc12) from Phytophthora capsici, which contributes to virulence and induces necrosis by triggering a distinct endoplasmic reticulum (ER) stress response through its interaction with Rab13-2. The necrotic cell death induced by Pc12 did not exhibit conventional effector-triggered immunity-mediated hypersensitive cell death, including the involvement of nucleotide-binding site leucine-rich repeat downstream signaling components and transcriptional reprogramming of defense-related genes. Instead, it alters the localization of ER-resident proteins and confines secretory proteins within the ER. Pc12 directly interacts with Rab13-2, which is primarily localized to the ER and Golgi apparatus, resulting in a diminished Rab13-2 signal on the Golgi apparatus. Furthermore, Rab13-2 exhibits increased affinity for its interactor, Rab escort protein 1, in the presence of Pc12. Structural predictions revealed that a specific residue of Rab13-2 is crucial for binding to the C-terminus of Pc12. Substitution of this residue reduced its interaction with Pc12 and impaired P. capsici infection while maintaining its interaction with Rab escort protein 1 and prenylated Rab acceptor 1. These findings provide insight into how a pathogen effector induces a distinct form of necrotic cell death to facilitate colonization of the host plant by disrupting the recycling of Rab13-2, a protein involved in vesicle trafficking at the ER-Golgi interface.

브레이크 오버 라이드 시스템을 기반으로 한 엔드 이펙터의 안전 평가 프로세스에 관한 연구

이준호,송기원 한국지식정보기술학회 2020 한국지식정보기술학회 논문지 Vol.15 No.2

As the development of various technologies and many studies underway, Medical Robots are used to treat various areas of treatment as they help in performing surgery. In particular, Surgical Robots, which account for the majority of Medical Robots, have diversified surgical operations and are actively conducting safety studies. However, safety accidents on End Effectors are frequent due to the inadequate control of the surgeon in charge of using Surgical Robots. The importance of FLS(Fundamentals of Laparoscopic Sugar) was then emphasized for Surgical Robots, a test that increased the proficiency of their physicians based on End Effectors. End Effector means a device that is typically attached to the end of the Surgical Robot to perform the required operation. Currently, the End Effector of the Surgical Robot is not immediately capable of handling accidents because the physician in charge must press the emergency stop button manually. In comparison, among systems related to cars, traffic and roads, the process of Brake Override System in which the functions of the parts operate first, regardless of human control. Thus, this paper study the process of automating the shutdown method of End Effector by utilizing the Safety Assessment Items of existing Surgical Robots and Processes of FLS, Brake Override System.

Mini-review: oomycete RXLR genes as effector-triggered immunity

Saima Arif,장현아,김미르,오상근 충남대학교 농업과학연구소 2018 Korean Journal of Agricultural Science Vol.45 No.4

Oomycetes are known to secrete a vast arsenal of effectors that modulate the host defense system as well as facilitate establishing a parasitic infection in plants. In recent years, tremendous progress has been made in the field of effectromics based on studies of oomycetes, especially the cytoplasmic family of RXLR effectors. Yet, the biology of the RXLR effector family is still poorly understood. There has been a consensus regarding the structure of the RXLR motif in the mycologist community. However, the function of the RXLR motif is still unclear. First, different models have suggested that the role of the RXLR motif is either in translocation to a target destination inside a host cell or in the cleavage of itself followed by secretion. Second, recent studies have suggested different functional models for the RXLR motif. According to a widely accepted model, the RXLR motif is directly involved in the translocation of effectors to target sites. In contrast, a new study has proposed that the RXLR motif is involved in secretion rather than translocation. Thus, this review is an attempt to summarize the recent advances made in the functional analysis of the N-terminal domain of RXLR effectors.

Against friend and foe: Type 6 effectors in plant-associated bacteria

류충민 한국미생물학회 2015 The journal of microbiology Vol.53 No.3

Bacterial secretion systems play critical roles in communicationwith neighboring bacteria and in the modulation ofhost immune responses via the secretion of small proteinscalled effectors. Several secretion systems have been identifiedand these are denoted types I–VII. Of these, the type VIsecretion system (T6SS) and its effectors were only recentlyelucidated. Most studies on the role and significance of theT6SS and its effectors have focused on human pathogens. In this review, type 6 effectors from plant-associated beneficialand pathogenic bacteria are discussed, including effectorsfrom Agrobacterium tumefaciens, Dickeya dadanti, Rhizobiumleguminosarum, Pectobacterium atroseptium, Ralstoniasolanacearum, Pseudomonas syringae, Pseudomonasfluorescens, and Pseudomonas protegens. Type 6 effectors actin symbiosis, biofilm formation, virulence, and interbacterialcompetition. Understanding the impact of type 6 effectorson pathogenesis will contribute to the management of bacterialpathogens in crop plants by allowing the manipulationof intra and inter-specific interactions.

Identification of Two Secreted in xylem 6 (SIX6) Genes in Fusarium oxysporum f. sp. fragariae of Korea Isolates

Lim Do Yoon,Park Han Na,Yoo Jea Hyuk,Lim Siyeon,Lee Bomi,Min Jiyoung,Kim Sun Ha,Lee Inha,Oh Sang-Keun 한국균학회 2024 한국균학회지 Vol.52 No.4

Strawberry Fusarium wilt, caused by Fusarium oxysporum f. sp. fragariae (FOF), poses a significant threat to strawberry production. FOF secretes effector proteins called “secreted in xylem” (SIX) into the plant's xylem, disrupting the defense responses in the plant. In this study the proteins SIX6a and SIX6b in FOF races 1 and 2, showing race-specific expression patterns, were identified. These genes encode effector proteins with a conserved signal peptide that is typical of fungal effectors. Differential expression in susceptible strawberries suggests that FOF races regulate these effectors differently, thereby contributing to variations in pathogenicity. Understanding these effectors is crucial for the development of racespecific resistance strategies to manage Fusarium wilt in strawberries.