scholarly journals OsExo70B1 Positively Regulates Disease Resistance to Magnaporthe oryzae in Rice

2020 ◽  
Vol 21 (19) ◽  
pp. 7049
Author(s):  
Hongna Hou ◽  
Jianbo Fang ◽  
Jiahui Liang ◽  
Zhijuan Diao ◽  
Wei Wang ◽  
...  
Keyword(s):  
Magnaporthe Oryzae ◽  
Early Stage ◽  
Plant Immunity ◽  
Fungal Growth ◽  
Defense Responses ◽  
Pr Genes ◽  
Pathogenesis Related ◽  
Important Regulator ◽  
A Subunit ◽  
Molecular Patterns

The exocyst, an evolutionarily conserved octameric protein complex, mediates tethering of vesicles to the plasma membrane in the early stage of exocytosis. Arabidopsis Exo70, a subunit of the exocyst complex, has been found to be involved in plant immunity. Here, we characterize the function of OsExo70B1 in rice. OsExo70B1 mainly expresses in leaf and shoot and its expression is induced by pathogen-associated molecular patterns (PAMPs) and rice blast fungus Magnaporthe oryzae (M. oryzae). Knocking out OsExo70B1 results in significantly decreased resistance and defense responses to M. oryzae compared to the wild type, including more disease lesions and enhanced fungal growth, downregulated expression of pathogenesis-related (PR) genes, and decreased reactive oxygen species accumulation. In contrast, the exo70B1 mutant does not show any defects in growth and development. Furthermore, OsExo70B1 can interact with the receptor-like kinase OsCERK1, an essential component for chitin reception in rice. Taken together, our data demonstrate that OsExo70B1 functions as an important regulator in rice immunity.

scholarly journals NPR1 and Redox Rhythmx: Connections, between Circadian Clock and Plant Immunity

2019 ◽  
Vol 20 (5) ◽  
pp. 1211 ◽  
Author(s):  
Jingjing Zhang ◽  
Ziyu Ren ◽  
Yuqing Zhou ◽  
Zheng Ma ◽  
Yanqin Ma ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Systemic Acquired Resistance ◽  
Nuclear Translocation ◽  
Plant Immunity ◽  
Acquired Resistance ◽  
Defense Responses ◽  
Diurnal Changes ◽  
Pr Genes ◽  
Pathogen Infection ◽  
Physiological Reactions

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.

scholarly journals Isolate specific responses of the non-host grass Brachypodium distachyon to the fungal pathogen Zymoseptoria tritici, compared to wheat.

2020 ◽  
Author(s):  
Ailsing Reilly ◽  
Sujit Jung Karki ◽  
Anthony Twamley ◽  
Anna M.M Tiley ◽  
Steven Kildea ◽  
...  
Keyword(s):  
Fungal Pathogen ◽  
Plant Immunity ◽  
Brachypodium Distachyon ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Pr Genes ◽  
Zymoseptoria Tritici ◽  
Expression Of Genes ◽  
Pathogenesis Related ◽  
Defence Gene Expression

Septoria tritici blotch (STB) is an important foliar disease of wheat that is caused by the fungal pathogen Zymoseptoria tritici. The grass Brachypodium distachyon has been used previously as a model system for cereal-pathogen interactions. In this study, we examined the non-host resistance (NHR) response of B. distachyon to two different Z. tritici isolates in comparison to wheat. These isolates vary in aggressiveness on wheat cv. Remus displaying significant differences in disease and pycnidia coverage. Using microscopy, we found that similar isolate specific responses were observed for H2O2 accumulation and cell death in both wheat and B. distachyon. Despite this, induction of isolate specific patterns of defence gene expression by Z. tritici did differ between B. distachyon and wheat. Our results suggest that phenylalanine ammonia lyase (PAL) expression may be important for NHR in B. distachyon while pathogenesis-related (PR) genes and expression of genes regulating reactive oxygen species (ROS) may be important to limit disease in wheat. Future studies of the B. distachyon-Z. tritici interaction may allow identification of conserved plant immunity targets which are responsible for the isolate specific responses observed in both plant species.

scholarly journals Hop stunt viroid: Effect on Host (Humulus lupulus) Transcriptome and Its Interactions With Hop Powdery Mildew (Podospheara macularis)

2017 ◽  
Vol 30 (10) ◽  
pp. 842-851 ◽  
Author(s):  
Madhu Kappagantu ◽  
Jeff M. Bullock ◽  
Mark E. Nelson ◽  
Kenneth C. Eastwell
Keyword(s):  
Powdery Mildew ◽  
Transcriptome Analysis ◽  
Plant Pathogens ◽  
Polymerase Chain Reaction Analysis ◽  
Defense Responses ◽  
Pr Genes ◽  
Stunt Viroid ◽  
Hop Stunt Viroid ◽  
Pathogenesis Related ◽  
Host Metabolism

Viroids are the smallest known plant pathogens that exploit host systems for their replication and cause diseases in many hosts. In this study, the host response of hop plants to Hop stunt viroid (HSVd) infection was studied through transcriptome analysis. RNA sequence analysis of hop leaves infected with HSVd revealed dynamic changes in hop gene expression. Defense-related genes and genes involved in lipid and terpenoid metabolism are the major categories that showed differential expression due to HSVd infection. Additionally, the effect of HSVd on development of hop powdery mildew (Podospheara macularis) (HPM) was studied. Transcriptome analysis followed by quantitative reverse transcription-polymerase chain reaction analysis showed that transcript levels of pathogenesis-related (PR) genes such as PR protein 1, chitinase, and thaumatin-like protein genes are induced in leaves infected with HPM alone. The response in these genes to HPM is significantly down-regulated in leaves with HSVd-HPM mixed infection. These results confirm that HSVd alters host metabolism, physiology, and plant defense responses. Nevertheless, in detached leaf assays, HPM consistently expanded faster on HSVd-negative leaves relative to HSVd-positive leaves. Although HSVd infection suppresses elements associated with the host immunity response, infection by HSVd is antagonistic to HPM infection of hops.

scholarly journals Nitric Oxide as a Mediator for Defense Responses

2013 ◽  
Vol 26 (3) ◽  
pp. 271-277 ◽  
Author(s):  
Diana Bellin ◽  
Shuta Asai ◽  
Massimo Delledonne ◽  
Hirofumi Yoshioka
Keyword(s):  
Nitric Oxide ◽  
Protein Function ◽  
Current Knowledge ◽  
Plant Immunity ◽  
Defense Responses ◽  
Rapid Induction ◽  
Physiological Relevance ◽  
Recognition Systems ◽  
Molecular Patterns ◽  
Sequential Recognition

Sequential recognition of invading microbes and rapid induction of plant immune responses comprise at least two recognition systems. Early basal defenses are initiated by pathogen-associated molecular patterns and pattern recognition receptors (PRR) in the plasma membrane. Pathogens produce effectors to suppress defense but plants, in turn, can sense such effectors by dominant plant resistance (R) gene products. Plant PRR and R proteins modulate signaling networks for defense responses that rely on rapid production of reactive nitrogen species (RNS) and reactive oxygen species (ROS). Recent research has shown that nitric oxide (NO) mainly mediates biological function through chemical reactions between locally controlled accumulation of RNS and proteins leading to potential alteration of protein function. Many proteins specifically regulated by NO and participating in signaling during plant defense response have been identified, highlighting the physiological relevance of these modifications in plant immunity. ROS function independently or in cooperation with NO during defense, modulating the RNS signaling functions through the entire process. This review provides an overview of current knowledge about regulatory mechanisms for NO burst and signaling, and crosstalk with ROS in response to pathogen attack.

scholarly journals Expression of the pathogenesis related proteins, NH-1, PAL, and lipoxygenase in the iranian Tarom and Khazar rice cultivars, in reaction to Rhizoctonia solani – the causal agent of rice sheath blight

2014 ◽  
Vol 54 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Mohammad Sayari ◽  
Valiollah Babaeizad ◽  
Mohammad Ali Tajick Ghanbari ◽  
Heshmat Rahimian
Keyword(s):  
Rhizoctonia Solani ◽  
Defense Responses ◽  
Sheath Blight ◽  
Causal Agent ◽  
Post Inoculation ◽  
Rice Sheath Blight ◽  
Defense Genes ◽  
Pr Genes ◽  
Pathogenesis Related ◽  
Expression Rate

Abstract Pathogenesis related (PR) genes of rice are among the most important defense genes in the interaction of rice with pathogens. In this study, the role of NH-1, several PR genes, phenylalanine ammonia-lyase (PAL), and lipoxygenase in the defense responses of rice against Rhizoctonia solani, the causal agent of rice sheath blight disease, was evaluated. The Tarom and Khazar cultivars (cvs), as resistant and susceptible genotypes, respectively, were used. The expression rate of defense genes in two-week-old seedlings inoculated with a virulent isolate of R. solani AG-I-1 A was investigated. The lesions in the Tarom cv were less than half the size of those on the Khazar cv. The expression scripts of the genes were calculated by quantative Real-Time PCR (RT-PCR). Results showed that the expression rate of all genes in the resistant cultivar was higher than that of the susceptible genotype, post inoculation. Analysis of data by the t-Student test also indicated significant differences in the expression level of the genes between Khazar and Tarom. The results of this study suggest that the investigated genes are involved in the resistance responses of rice against the sheath blight agent. For the first time, the induction of PR-5, PR-9, PR-10, PR-12, PR-13, and NH-1 was observed in this study in the resistant and susceptible Iranian cultivars of rice following attacks by R. solani.

scholarly journals MKK4/5-MPK3/6 Cascade Regulates Agrobacterium-Mediated Transformation by Modulating Plant Immunity in Arabidopsis

2021 ◽  
Vol 12 ◽  
Author(s):  
Tengfei Liu ◽  
Li Cao ◽  
Yuanyuan Cheng ◽  
Jing Ji ◽  
Yongshu Wei ◽  
...  
Keyword(s):  
Plant Defense ◽  
Early Stage ◽  
Plant Immunity ◽  
Defense Responses ◽  
Mitogen Activated Protein Kinase ◽  
Ros Production ◽  
Crown Gall Disease ◽  
Mitogen Activated Protein ◽  
Defense Response Genes ◽  
Signaling Components

Agrobacterium tumefaciens is a specialized plant pathogen that causes crown gall disease and is commonly used for Agrobacterium-mediated transformation. As a pathogen, Agrobacterium triggers plant immunity, which affects transformation. However, the signaling components and pathways in plant immunity to Agrobacterium remain elusive. We demonstrate that two Arabidopsis mitogen-activated protein kinase kinases (MAPKKs) MKK4/MKK5 and their downstream mitogen-activated protein kinases (MAPKs) MPK3/MPK6 play major roles in both Agrobacterium-triggered immunity and Agrobacterium-mediated transformation. Agrobacteria induce MPK3/MPK6 activity and the expression of plant defense response genes at a very early stage. This process is dependent on the MKK4/MKK5 function. The loss of the function of MKK4 and MKK5 or their downstream MPK3 and MPK6 abolishes plant immunity to agrobacteria and increases transformation frequency, whereas the activation of MKK4 and MKK5 enhances plant immunity and represses transformation. Global transcriptome analysis indicates that agrobacteria induce various plant defense pathways, including reactive oxygen species (ROS) production, ethylene (ET), and salicylic acid- (SA-) mediated defense responses, and that MKK4/MKK5 is essential for the induction of these pathways. The activation of MKK4 and MKK5 promotes ROS production and cell death during agrobacteria infection. Based on these results, we propose that the MKK4/5-MPK3/6 cascade is an essential signaling pathway regulating Agrobacterium-mediated transformation through the modulation of Agrobacterium-triggered plant immunity.

scholarly journals Poaceae-specific cell wall-derived oligosaccharides activate plant immunity via OsCERK1 during Magnaporthe oryzae infection in rice

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chao Yang ◽  
Rui Liu ◽  
Jinhuan Pang ◽  
Bin Ren ◽  
Huanbin Zhou ◽  
...  
Keyword(s):  
Cell Wall ◽  
Immune Responses ◽  
Magnaporthe Oryzae ◽  
Plant Cell Wall ◽  
Plant Immunity ◽  
Host Cells ◽  
Specific Cell ◽  
Chitin Binding Protein ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns

AbstractMany phytopathogens secrete cell wall degradation enzymes (CWDEs) to damage host cells and facilitate colonization. As the major components of the plant cell wall, cellulose and hemicellulose are the targets of CWDEs. Damaged plant cells often release damage-associated molecular patterns (DAMPs) to trigger plant immune responses. Here, we establish that the fungal pathogen Magnaporthe oryzae secretes the endoglucanases MoCel12A and MoCel12B during infection of rice (Oryza sativa). These endoglucanases target hemicellulose of the rice cell wall and release two specific oligosaccharides, namely the trisaccharide 31-β-D-Cellobiosyl-glucose and the tetrasaccharide 31-β-D-Cellotriosyl-glucose. 31-β-D-Cellobiosyl-glucose and 31-β-D-Cellotriosyl-glucose bind the immune receptor OsCERK1 but not the chitin binding protein OsCEBiP. However, they induce the dimerization of OsCERK1 and OsCEBiP. In addition, these Poaceae cell wall-specific oligosaccharides trigger a burst of reactive oxygen species (ROS) that is largely compromised in oscerk1 and oscebip mutants. We conclude that 31-β-D-Cellobiosyl-glucose and 31-β-D-Cellotriosyl-glucose are specific DAMPs released from the hemicellulose of rice cell wall, which are perceived by an OsCERK1 and OsCEBiP immune complex during M. oryzae infection in rice.

scholarly journals Genome-Wide Identification and Expression of Chitinase Class I Genes in Garlic (Allium sativum L.) Cultivars Resistant and Susceptible to Fusarium proliferatum

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 720
Author(s):  
Mikhail A. Filyushin ◽  
Olga K. Anisimova ◽  
Elena Z. Kochieva ◽  
Anna V. Shchennikova
Keyword(s):  
Allium Sativum ◽  
Early Stage ◽  
Fungal Growth ◽  
Fusarium Proliferatum ◽  
Class I ◽  
Mrna Levels ◽  
Genome Wide ◽  
Pathogenesis Related ◽  
Chitinase Genes ◽  
Related Proteins

Vegetables of the Allium genus are prone to infection by Fusarium fungi. Chitinases of the GH19 family are pathogenesis-related proteins inhibiting fungal growth through the hydrolysis of cell wall chitin; however, the information on garlic (Allium sativum L.) chitinases is limited. In the present study, we identified seven class I chitinase genes, AsCHI1–7, in the A. sativum cv. Ershuizao genome, which may have a conserved function in the garlic defense against Fusarium attack. The AsCHI1–7 promoters contained jasmonic acid-, salicylic acid-, gibberellins-, abscisic acid-, auxin-, ethylene-, and stress-responsive elements associated with defense against pathogens. The expression of AsCHI2, AsCHI3, and AsCHI7 genes was constitutive in Fusarium-resistant and -susceptible garlic cultivars and was mostly induced at the early stage of F. proliferatum infection. In roots, AsCHI2 and AsCHI3 mRNA levels were increased in the susceptible and decreased in the resistant cultivar, whereas in cloves, AsCHI7 and AsCHI5 expression was decreased in the susceptible but increased in the resistant plants, suggesting that these genes are involved in the garlic response to Fusarium proliferatum attack. Our results provide insights into the role of chitinases in garlic and may be useful for breeding programs to increase the resistance of Allium crops to Fusarium infections.

scholarly journals Constitutive Expression of Arabidopsis Senescence Associated Gene 101 in Brachypodium distachyon Enhances Resistance to Puccinia brachypodii and Magnaporthe oryzae

Plants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1316
Author(s):  
Ning Wang ◽  
Na Song ◽  
Zejun Tang ◽  
Xiaojie Wang ◽  
Zhensheng Kang ◽  
...  
Keyword(s):  
Transgenic Plants ◽  
Magnaporthe Oryzae ◽  
Plant Immunity ◽  
Brachypodium Distachyon ◽  
Constitutive Expression ◽  
Wild Type ◽  
Homologous Genes ◽  
Pathogenesis Related ◽  
Salicylic Acid Accumulation ◽  
Pathogenesis Related Gene

Brachypodium distachyon, as an effective model of cereal grains, is susceptible to most destructive cereal pathogens. Senescence associated gene 101 (SAG101) has been studied extensively in Arabidopsis. SAG101 is one of the important regulators of plant immunity. However, no homologous genes of AtSAG101 were found in B. distachyon. In this study, the AtSAG101 gene was transformed into B. distachyon. Three transgenic plant lines containing the AtSAG101 gene were confirmed by PCR and GUS gene activity. There were fewer Puccinia brachypodii urediospores in the AtSAG101-overexpressing plants compared to wild type plants. P. brachypodii biomass was obviously decreased in AtSAG101 transgenic plants. The length of infection hyphae and infection unit areas of P. brachypodii were significantly limited in transgenic plants. Moreover, there were small lesions in AtSAG101 transgenic plants challenged by Magnaporthe oryzae. Salicylic acid accumulation was significantly increased, which led to elevated pathogenesis-related gene expression in transgenic B. distachyon inoculated by P. brachypodii or M. oryzae compared to wild type plants. These results were consistent with infected phenotypes. Overexpression of AtSAG101 in B. distachyon caused resistance to M. oryzae and P. brachypodii. These results suggest that AtSAG101 could regulate plant resistance in B. distachyon.

scholarly journals XCP1 is a caspase that proteolyzes Pathogenesis-related protein 1 to produce the cytokine CAPE9 for systemic immunity in Arabidopsis

2021 ◽  
Author(s):  
Ying-Lan Chen ◽  
Fan-Wei Lin ◽  
Kai-Tan Cheng ◽  
Hung-Yu Wang ◽  
Thomas Efferth ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Plant Immunity ◽  
Related Protein ◽  
Proteolytic Activation ◽  
Systemic Immunity ◽  
Pathogenesis Related Protein ◽  
Pathogenesis Related ◽  
Comparable Activity ◽  
Molecular Patterns ◽  
Substrate Motif

Abstract Proteolytic activation of cytokines regulates immunity in diverse organisms. In animals, cysteine-dependent aspartate-specific proteases (caspases) play central roles in cytokine maturation. Although the proteolytic production of peptide cytokines is also essential for plant immunity, evidence for a plant caspase is still lacking. In this study, we discovered that proteolysis of a caspase-like substrate motif “CNYD” within Pathogenesis-related protein 1 (AtPR1) in Arabidopsis generates an immunomodulatory cytokine (AtCAPE9). Salicylic acid enhances CNYD-targeted protease activity and the proteolytic release of AtCAPE9 from AtPR1 in Arabidopsis. We show that this process involves a caspase, identified as Xylem cysteine peptidase 1 (XCP1). XCP1 exhibits a calcium-modulated pH-activity profile and a comparable activity to human caspases. XCP1 is required to induce systemic immunity triggered by pathogen-associated molecular patterns. This work reveals XCP1 as the first known plant caspase, which produces the cytokine AtCAPE9 from the canonical salicylic acid signaling marker PR1 to activate systemic immunity.

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