scholarly journals Erwinia carotovora subsp. carotovora and Erwinia-Derived Elicitors HrpN and PehA Trigger Distinct but Interacting Defense Responses and Cell Death in Arabidopsis

2003 ◽  
Vol 16 (3) ◽  
pp. 179-187 ◽  
Author(s):  
Tarja Kariola ◽  
Tiina A. Palomäki ◽  
Günter Brader ◽  
E. Tapio Palva
Keyword(s):  
Erwinia Carotovora ◽  
Soft Rot ◽  
Defense Responses ◽  
Systemic Resistance ◽  
Marker Genes ◽  
Plant Responses ◽  
Virulence Determinants ◽  
Lesion Formation ◽  
Defense Gene Expression ◽  
Defense Signaling

We have used an hrp-positive strain of the soft rot pathogen Erwinia carotovora subsp. carotovora to elucidate plant responses to this bacterial necrotroph. Purified virulence determinants, harpin (HrpN) and polygalacturonase (PehA), were used as tools to facilitate this analysis. We show that HrpN elicits lesion formation in Arabidopsis and tobacco and triggers systemic resistance in Arabidopsis. Establishment of resistance is accompanied by the expression of salicylic acid (SA)-dependent, but also jasmonate/ethylene (JA/ET)-dependent, marker genes PR1 and PDF1.2, respectively, suggesting that both SA-dependent and JA/ET-dependent defense pathways are activated. Use of pathway-specific mutants and transgenic NahG plants show that both pathways are required for the induction of resistance. Arabidopsis plants treated simultaneously with both elictors PehA, known to trigger only JA/ET-dependent defense signaling, and HrpN react with accelerated and enhanced induction of the marker genes PR1 and PDF1.2 both locally and systemically. This mutual amplification of defense gene expression involves both SA-dependent and JA/ET-dependent defense signaling. The two elicitors produced by E. carotovora subsp. carotovora also cooperate in triggering increased production of superoxide and lesion formation.

scholarly journals Type III Secretion Contributes to the Pathogenesis of the Soft-Rot Pathogen Erwinia carotovora: Partial Characterization of the hrp Gene Cluster

2001 ◽  
Vol 14 (8) ◽  
pp. 962-968 ◽  
Author(s):  
A. Rantakari ◽  
O. Virtaharju ◽  
S. Vähämiko ◽  
S. Taira ◽  
E. T. Palva ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Type Iii Secretion ◽  
Plant Pathogens ◽  
Erwinia Carotovora ◽  
Soft Rot ◽  
Hypersensitive Reaction ◽  
Virulence Determinants ◽  
Type Iii ◽  
Hrp Genes ◽  
Soft Rot Erwinia

The virulence of soft-rot Erwinia species is dependent mainly upon secreted enzymes such as pectinases, pectin lyases, and proteases that cause maceration of plant tissue. Some soft-rot Erwinia spp. also harbor genes homologous to the hypersensitive reaction and pathogenesis (hrp) gene cluster, encoding components of the type III secretion system. The hrp genes are essential virulence determinants for numerous nonmacerating gram-negative plant pathogens but their role in the virulence of soft-rot Erwinia spp. is not clear. We isolated and characterized 11 hrp genes of Erwinia carotovora subsp. carotovora. Three putative σL-dependent Hrp box promoter sequences were found. The genes were expressed when the bacteria were grown in Hrp-inducing medium. The operon structure of the hrp genes was determined by mRNA hybridization, and the results were in accordance with the location of the Hrp boxes. An E. carotovora strain with mutated hrcC, an essential hrp gene, was constructed. The hrcC¯ strain was able to multiply and cause disease in Arabidopsis, but the population kinetics were altered so that growth was delayed during the early stages of infection.

scholarly journals Pochonia chlamydosporia Isolate PC-170-Induced Expression of Marker Genes for Defense Pathways in Tomatoes Challenged by Different Pathogens

2021 ◽  
Vol 9 (9) ◽  
pp. 1882
Author(s):  
Xia Zhuang ◽  
Jian-Long Zhao ◽  
Miao Bai ◽  
Xing-Xing Ping ◽  
Yan-Lin Li ◽  
...  
Keyword(s):  
Jasmonic Acid ◽  
Defense Responses ◽  
Systemic Resistance ◽  
Marker Genes ◽  
Root Knot Nematode ◽  
Pochonia Chlamydosporia ◽  
Susceptibility To Infection ◽  
Nematode Eggs ◽  
Mutant Lines ◽  
Ja Signaling

Pochonia chlamydosporia is a fungal parasite of nematode eggs. Studies have shown that some strains of Pochonia chlamydosporia can promote plant growth and induce plants’ systemic resistance to root-knot nematodes by colonizing in their roots. This study aimed to verify the effect of the PC-170 strain on tomato growth and systemic resistance. Split-root experiments were conducted to observe the systemic resistance induced by PC-170. To explore the defense pathway that was excited due to the colonization by PC-170, we tested the expression of marker genes for defense pathways, and used mutant lines to verify the role of plant defense pathways. Our results showed that PC-170 can colonize roots, and promotes growth. We found a role for jasmonic acid (JA) in modulating tomato colonization by PC-170. PC-170 can activate tomato defense responses to reduce susceptibility to infection by the root-knot nematode Meloidogyne incognita, and induced resistance to some pathogens in tomatoes. The marker genes of the defense pathway were significantly induced after PC-170 colonization. However, salicylic acid (SA)- and jasmonic acid (JA)-dependent defenses in roots were variable with the invasion of different pathogens. Defense pathways play different roles at different points in time. SA- and JA-dependent defense pathways were shown to cross-communicate. Different phytohormones have been involved in tomato plants’ responses against different pathogens. Our study confirmed that adaptive JA signaling is necessary to regulate PC-170 colonization and induce systemic resistance in tomatoes.

scholarly journals Identification and Characterization of Nip, Necrosis-Inducing Virulence Protein of Erwinia carotovora subsp. carotovora

2004 ◽  
Vol 17 (12) ◽  
pp. 1366-1375 ◽  
Author(s):  
Laura Mattinen ◽  
Marina Tshuikina ◽  
Andres Mäe ◽  
Minna Pirhonen
Keyword(s):  
Leaf Tissue ◽  
Erwinia Carotovora ◽  
Soft Rot ◽  
Bacterial Cells ◽  
Virulence Determinants ◽  
Virulence Protein ◽  
Encoding Gene ◽  
Rot Disease ◽  
Identification And Characterization

Erwinia carotovora subsp. carotovora is a gram-negative bacterium that causes soft rot disease of many cultivated crops. When a collection of E. carotovora subsp. carotovora isolates was analyzed on a Southern blot using the harpin-encoding gene hrpN as probe, several harpinless isolates were found. Regulation of virulence determinants in one of these, strain SCC3193, has been characterized extensively. It is fully virulent on potato and in Arabidopsis thaliana. An RpoS (SigmaS) mutant of SCC3193, producing elevated levels of secreted proteins, was found to cause lesions resembling the hypersensitive response when infiltrated into tobacco leaf tissue. This phenotype was evident only when bacterial cells had been cultivated on solid minimal medium at low pH and temperature. The protein causing the cell death was purified and sequenced, and the corresponding gene was cloned. The deduced sequence of the necrosis-inducing protein (Nip) showed homology to necrosis- and ethylene-inducing elicitors of fungi and oomycetes. A mutant strain of E. carotovora subsp. carotovora lacking the nip gene showed reduced virulence in potato tuber assay but was unaffected in virulence in potato stem or on other tested host plants.

scholarly journals Ecological adaptations influence the susceptibility of plants in the genus Zantedeschia to soft rot Pectobacterium spp.

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yelena Guttman ◽  
Janak Raj Joshi ◽  
Nofar Chriker ◽  
Nirmal Khadka ◽  
Maya Kleiman ◽  
...  
Keyword(s):  
Bacterial Colonization ◽  
Expression Patterns ◽  
Leaf Tissue ◽  
Soft Rot ◽  
Systemic Resistance ◽  
Marker Genes ◽  
Ecological Adaptations ◽  
Leaf Surfaces ◽  
Rot Disease ◽  
Group Species

AbstractSoft rot disease caused by Pectobacterium spp. is responsible for severe agricultural losses in potato, vegetables, and ornamentals. The genus Zantedeschia includes two botanical groups of tuberous ornamental flowers that are highly susceptible to the disease. Previous studies revealed that Z. aethiopica, a member of the section Zantedeschia, is significantly more resistant to Pectobacterium spp. than members of the same genus that belong to the section Aestivae. During early infection, we found different patterns of bacterial colonization on leaves of hosts belonging to the different sections. Similar patterns of bacterial colonization were observed on polydimethylsiloxane (PDMS) artificial inert replicas of leaf surfaces. The replicas confirmed the physical effect of leaf texture, in addition to a biochemical plant–bacterium interaction. The differential patterns may be associated with the greater roughness of the abaxial leaf surfaces of Aestivae group that have evolutionarily adapted to mountainous environments, as compared to Zantedeschia group species that have adapted to warm, marshy environments. Transverse leaf sections also revealed compact aerenchyma and reduced the total volume of leaf tissue air spaces in Aestivae members. Finally, an analysis of defense marker genes revealed differential expression patterns in response to infection, with significantly higher levels of lipoxygenase 2 (lox2) and phenylalanine ammonia lyase (pal) observed in the more resistant Z. aethiopica, suggesting greater activation of induced systemic resistance (ISR) mechanisms in this group. The use of Zantedeschia as a model plant sheds light on how natural ecological adaptations may underlay resistance to bacterial soft rot in cultivated agricultural environments.

scholarly journals Potato Homologs of Arabidopsis thaliana Genes Functional in Defense Signaling—Identification, Genetic Mapping, and Molecular Cloning

2005 ◽  
Vol 18 (10) ◽  
pp. 1107-1119 ◽  
Author(s):  
Karolina M. Pajerowska ◽  
Jane E. Parker ◽  
Christiane Gebhardt
Keyword(s):  
Arabidopsis Thaliana ◽  
Plant Pathogens ◽  
Molecular Mechanisms ◽  
Expressed Sequence Tag ◽  
Quantitative Resistance ◽  
Erwinia Carotovora ◽  
Soft Rot ◽  
Signaling Cascades ◽  
Defense Signaling ◽  
Expressed Sequence

Defense against pests and pathogens is a fundamental process controlled by similar molecular mechanisms in all flowering plants. Using Arabidopsis thaliana as a model, steps of the signal transduction pathways that link pathogen recognition to defense activation have been identified and corresponding genes have been characterized. Defense signaling (DS) genes are functional candidates for controlling natural quantitative variation of resistance to plant pathogens. Nineteen Arabidopsis genes operating in defense signaling cascades were selected. Solanaceae EST (expressed sequence tag) databases were employed to identify the closest homologs of potato (Solanum tuberosum). Sixteen novel DS potato homologs were positioned on the molecular maps. Five DS homologs mapped close to known quantitative resistance loci (QRL) against the oomycete Phytophthora infestans causing late blight and the bacterium Erwinia carotovora subsp. atroseptica causing blackleg of stems and tuber soft rot. The five genes are positional candidates for QRL and are highly sequence related to Arabidopsis genes AtSGT1b, AtPAD4, and AtAOS. Full-length complementary DNA and genomic sequences were obtained for potato genes StSGT1, StPAD4, and StEDS1, the latter being a putative interactor of StPAD4. Our results form the basis for further studies on the contributions of these candidate genes to natural variation of potato disease resistance.

Screening of Antagonistic Bacterium to Control Konjac Soft Rot

2013 ◽  
Vol 726-731 ◽  
pp. 4427-4430
Author(s):  
Guo Hua Chen
Keyword(s):  
Bacterial Strain ◽  
Bacterial Pathogen ◽  
Erwinia Carotovora ◽  
Soft Rot ◽  
Field Trials ◽  
Antagonistic Effect ◽  
Soil Samples ◽  
Plate Method ◽  
Antagonistic Bacterium

Konjac soft rot is a bottleneck limiting konjac yield caused by bacterial strain of Erwinia carotovora var. carotovora. In order to control konjac soft rot, soil samples were collected, and each sample was spread on surface of a plate seeded with E. carotovora var. carotovora in advance. Strains expressing antagonistic activities were selected and then isolated with streak plate method. One bacterial strain (named Z10) was obtained from soil by this method. In field trials, strain Z10 still showed antagonistic effect against the bacterial pathogen.

scholarly journals Caterpillar salivary enzymes: "eliciting" a response

2004 ◽  
Vol 85 (1) ◽  
pp. 33-37 ◽  
Author(s):  
Magali Merkx-Jacques ◽  
Jacqueline C. Bede
Keyword(s):  
Artificial Diet ◽  
Spodoptera Exigua ◽  
Induced Defense ◽  
Defense Responses ◽  
Beet Armyworm ◽  
Herbivorous Insect ◽  
Plant Responses ◽  
Plant Defense Responses ◽  
Induced Defense Responses ◽  
Bertha Armyworm

Abstract Plants exhibit remarkable plasticity in their ability to differentiate between herbivorous insect species and subtly adjust their defense responses to target distinct pests. One key mechanism used by plants to recognize herbivorous caterpillars is elicitors present in their oral secretions; however, these elicitors not only cause the induction of plant defenses but recent evidence suggests that they may also suppress plant responses. The absence of “expected changes” in induced defense responses of insect-infested plants has been attributed to hydrogen peroxide produced by caterpillar salivary glucose oxidase (GOX). Activity of this enzyme is variable among caterpillar species; it was detected in two generalist caterpillars, the beet armyworm (Spodoptera exigua) and the bertha armyworm (Mamestra configurata), but not in other generalist or specialist caterpillar species tested. In the beet armyworm, GOX activity fluctuated over larval development with high activity associated with the salivary glands of fourth instars. Larval salivary GOX activity of the beet armyworm and the bertha armyworm was observed to be significantly higher in caterpillars reared on artificial diet as compared with those reared on Medicago truncatula plants. This implies that a factor in the diet is involved in the regulation of caterpillar salivary enzyme activity. Therefore, plant diet may be regulating caterpillar oral elicitors that are involved in the regulation of plant defense responses: our goal is to understand these two processes.

scholarly journals Morphological and Molecular Analyses of Host and Nonhost Interactions Involving Barley and Wheat and the Covered Smut Pathogen Ustilago hordei

2010 ◽  
Vol 23 (12) ◽  
pp. 1619-1634 ◽  
Author(s):  
Denis A. Gaudet ◽  
Yuanyuan Wang ◽  
Carolyn Penniket ◽  
Z. X. Lu ◽  
Guus Bakkeren ◽  
...  
Keyword(s):  
Lipid Transfer Protein ◽  
Expression Patterns ◽  
Fluorescent Microscopy ◽  
Defense Responses ◽  
Lipid Transfer ◽  
Defense Gene Expression ◽  
Basal Resistance ◽  
Morphological Defense ◽  
Pathway Expression ◽  
Ustilago Hordei

Ustilago hordei interactions on coleoptiles of barley host cultivars Odessa (compatible), Hannchen (incompatible, carrying the Ruh1 resistance gene), and on nonhost Neepawa wheat were studied using light and fluorescent microscopy. Autofluorescence, mainly caused by callose accumulation, was more rapidly expressed in nonhost wheat at 30 to 72 h compared with the incompatible reaction between 72 and 144 h. Microarray results demonstrated that more than half of the 893 differentially regulated genes were observed in Neepawa; of these genes, 45% fell into the defense- and stress-related classes in Neepawa compared with 25 and 37% in Odessa and Hannchen, respectively. Their expression coincided with the early morphological defense responses observed and were associated with the jasmonic acid and ethylene (JA/ET) signaling pathway. Expression patterns in Odessa and Hannchen were similar, involving fewer genes and coinciding with later morphological defense responses of these varieties. Although no visible hypersensitive response was apparent in Hannchen or Neepawa, specific upregulation of hypersensitivity-related proteins was observed, such as beta-VPE at 48 h. Expression levels of the callose synthase gene were closely associated with callose accumulation. Differential responses in defense-gene expression among disease reaction types included upregulation of PR-1.1b and downregulation of a nonspecific lipid transfer protein in the incompatible and compatible interactions, respectively. Transcript levels of EDS1 and PAD4, involved in both basal resistance and R-mediated resistance to avirulent pathogens, were up-regulated during both nonhost and Ruh1-mediated resistance. Application of methyl-jasmonate, salicylic acid and ET to leaves revealed that only PR1.1b is strongly up-regulated by all three compounds, while the majority of the defense-related genes are only slightly up-regulated by these signaling compounds.

scholarly journals Role of Ca2+ in Mediating Plant Responses to Extracellular ATP and ADP

2018 ◽  
Vol 19 (11) ◽  
pp. 3590 ◽  
Author(s):  
Greg Clark ◽  
Stanley Roux
Keyword(s):  
Cytosolic Calcium ◽  
Defense Responses ◽  
Receptor Activation ◽  
Extracellular Atp ◽  
Extracellular Nucleotides ◽  
Nucleoside Triphosphate ◽  
Plant Responses ◽  
Downstream Signaling ◽  
Nucleoside Triphosphate Diphosphohydrolase

Among the most recently discovered chemical regulators of plant growth and development are extracellular nucleotides, especially extracellular ATP (eATP) and extracellular ADP (eADP). Plant cells release ATP into their extracellular matrix under a variety of different circumstances, and this eATP can then function as an agonist that binds to a specific receptor and induces signaling changes, the earliest of which is an increase in the concentration of cytosolic calcium ([Ca2+]cyt). This initial change is then amplified into downstream-signaling changes that include increased levels of reactive oxygen species and nitric oxide, which ultimately lead to major changes in the growth rate, defense responses, and leaf stomatal apertures of plants. This review presents and discusses the evidence that links receptor activation to increased [Ca2+]cyt and, ultimately, to growth and diverse adaptive changes in plant development. It also discusses the evidence that increased [Ca2+]cyt also enhances the activity of apyrase (nucleoside triphosphate diphosphohydrolase) enzymes that function in multiple subcellular locales to hydrolyze ATP and ADP, and thus limit or terminate the effects of these potent regulators.

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