scholarly journals Differential Induction of the Arabidopsis thaliana Thi2.1 Gene by Fusarium oxysporum f. sp. matthiolae

1998 ◽  
Vol 11 (6) ◽  
pp. 523-529 ◽  
Author(s):  
Petra Epple ◽  
Alberto Vignutelli ◽  
Klaus Apel ◽  
Holger Bohlmann
Keyword(s):  
Signal Transduction ◽  
Arabidopsis Thaliana ◽  
Fusarium Oxysporum ◽  
Signal Transduction Pathway ◽  
Transcript Level ◽  
Recognition System ◽  
Gus Expression ◽  
Necrotrophic Fungi ◽  
Pathogenesis Related ◽  
The Uk

The Arabidopsis thaliana Thi2.1 gene is inducible by necrotrophic fungi through a signal transduction pathway different from that for pathogenesis-related (PR) proteins. We have identified three ecotypes that are susceptible (Col-2, Ler, and Ws) and two ecotypes that are resistant (Mt-0 and Uk-4) to spray inoculation with Fusarium oxysporum f. sp. matthiolae. The Thi2.1 transcript level after infection correlates with resistance, being 5 to 10 times higher in the resistant than in the susceptible ecotypes. The β-glucuronidase (GUS) expression of a Thi2.1-promoter-uidA fusion (with a promoter derived from Col-2) is on the average almost 10 times higher in the Uk-4 background than in the Col-2 background. This confirms the results obtained by Northern (RNA) blots and indicates that Uk-4, and probably other resistant ecotypes too, might have a more sensitive recognition system for F. oxysporum f. sp. matthiolae or might have a signal transduction system that gives a higher amplification of the original recognition signal. Our results suggest a role of the Thi2.1 gene in resistance against F. oxysporum f. sp. matthiolae and perhaps other necrotrophic fungi.

scholarly journals Coupling of Cell Division and Differentiation in Arabidopsis thaliana Cultured Cells with Interaction of Ethylene and ABA Signaling Pathways

Life ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 15
Author(s):  
Novikova ◽  
Stepanchenko ◽  
Zorina ◽  
Nosov ◽  
Rakitin ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Signal Transduction ◽  
Arabidopsis Thaliana ◽  
Cell Division ◽  
Cell Differentiation ◽  
Signal Transduction Pathway ◽  
Transduction Pathway ◽  
Aba Signaling ◽  
Exogenous Aba ◽  
Ethylene Signal

Recent studies indicate direct links between molecular cell cycle and cell differentiation machineries. Ethylene and abscisic acid (ABA) are known to affect cell division and differentiation, but the mechanisms of such effects are poorly understood. As ethylene and ABA signaling routes may interact, we examined their involvement in cell division and differentiation in cell tissue cultures derived from several Arabidopsis thaliana plants: wild type (Col-0), and ethylene-insensitive mutants etr1-1, ctr1-1, and ein2-1. We designed an experimental setup to analyze the growth-related parameters and molecular mechanisms in proliferating cells upon short exposure to ABA. Here, we provide evidence for the ethylene–ABA signaling pathways’ interaction in the regulation of cell division and differentiation as follows: (1) when the ethylene signal transduction pathway is functionally active (Col-0), the cells actively proliferate, and exogenous ABA performs its function as an inhibitor of DNA synthesis and division; (2) if the ethylene signal is not perceived (etr1-1), then, in addition to cell differentiation (tracheary elements formation), cell death can occur. The addition of exogenous ABA can rescue the cells via increasing proliferation; (3) if the ethylene signal is perceived, but not transduced (ein2-1), then cell differentiation takes place—the latter is enhanced by exogenous ABA while cell proliferation is reduced; (4) when the signal transduction pathway is constitutively active, the cells begin to exit the cell cycle and proceed to endo-reduplication (ctr1-1). In this case, the addition of exogenous ABA promotes reactivation of cell division.

scholarly journals Differential Expression of Fungal Genes Determines the Lifestyle of Plectosphaerella Strains During Arabidopsis thaliana Colonization

2020 ◽  
Vol 33 (11) ◽  
pp. 1299-1314 ◽  
Author(s):  
Antonio Muñoz-Barrios ◽  
Sara Sopeña-Torres ◽  
Brisa Ramos ◽  
Gemma López ◽  
Irene del Hierro ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
In Planta ◽  
Necrotrophic Fungi ◽  
Pathogenesis Related ◽  
Nonpathogenic Strain ◽  
Genes Encoding ◽  
Fungal Genes ◽  
Growth Adaptation

The fungal genus Plectosphaerella comprises species and strains with different lifestyles on plants, such as P. cucumerina, which has served as model for the characterization of Arabidopsis thaliana basal and nonhost resistance to necrotrophic fungi. We have sequenced, annotated, and compared the genomes and transcriptomes of three Plectosphaerella strains with different lifestyles on A. thaliana, namely, PcBMM, a natural pathogen of wild-type plants (Col-0), Pc2127, a nonpathogenic strain on Col-0 but pathogenic on the immunocompromised cyp79B2 cyp79B3 mutant, and P0831, which was isolated from a natural population of A. thaliana and is shown here to be nonpathogenic and to grow epiphytically on Col-0 and cyp79B2 cyp79B3 plants. The genomes of these Plectosphaerella strains are very similar and do not differ in the number of genes with pathogenesis-related functions, with the exception of secreted carbohydrate-active enzymes (CAZymes), which are up to five times more abundant in the pathogenic strain PcBMM. Analysis of the fungal transcriptomes in inoculated Col-0 and cyp79B2 cyp79B3 plants at initial colonization stages confirm the key role of secreted CAZymes in the necrotrophic interaction, since PcBMM expresses more genes encoding secreted CAZymes than Pc2127 and P0831. We also show that P0831 epiphytic growth on A. thaliana involves the transcription of specific repertoires of fungal genes, which might be necessary for epiphytic growth adaptation. Overall, these results suggest that in-planta expression of specific sets of fungal genes at early stages of colonization determine the diverse lifestyles and pathogenicity of Plectosphaerella strains.

scholarly journals Chemically Induced Virus Resistance in Arabidopsis thaliana Is Independent of Pathogenesis-Related Protein Expression and the NPR1 Gene

2002 ◽  
Vol 15 (1) ◽  
pp. 75-81 ◽  
Author(s):  
Chui Eng Wong ◽  
Rachael A. J. Carson ◽  
John P. Carr
Keyword(s):  
Arabidopsis Thaliana ◽  
Induced Resistance ◽  
Alternative Oxidase ◽  
Signal Transduction Pathway ◽  
Plant Viruses ◽  
Chemically Induced ◽  
Pathogenesis Related Protein ◽  
Pathogenesis Related ◽  
Distinct Branch ◽  
Resistance To Viruses

Salicylic acid (SA) treatment triggers inhibition of replication or movement of several positive-sense RNA plant viruses in tobacco. This resistance can also be stimulated by nonlethal concentrations of cyanide and antimycin A (AA) without triggering induction of pathogenesis-related PR-1 protein genes. In two ecotypes of Arabidopsis thaliana (Columbia and Nössen), SA-induced resistance to a tobamovirus, Turnip vein clearing virus (TVCV), was also induced by nonlethal concentrations of cyanide and AA without concomitant induction of PR-1 gene expression. Furthermore, chemically induced resistance to TVCV, as well as the induction of the plant mitochondrial alternative oxidase (a potential target for the chemicals), was independent of NPR1, a gene that plays a key role downstream of SA in the induction of PR proteins. The chemically induced resistance to TVCV appeared to be due to inhibition of replication at the site of inoculation. Taken together, these results show that in Arabidopsis, as in tobacco, resistance to viruses can be induced via a distinct branch of the defensive signal transduction pathway. This suggests that the existence of this virus-specific branch may be widespread among plants.

Characterization of a Salicylic Acid-Insensitive Mutant (sai1) of Arabidopsis thaliana, Identified in a Selective Screen Utilizing the SA-Inducible Expression of the tms2 Gene

1997 ◽  
Vol 10 (1) ◽  
pp. 69-78 ◽  
Author(s):  
Jyoti Shah ◽  
Frank Tsui ◽  
Daniel F. Klessig
Keyword(s):  
Signal Transduction ◽  
Arabidopsis Thaliana ◽  
Salicylic Acid ◽  
Root Growth ◽  
Signal Transduction Pathway ◽  
Inducible Expression ◽  
Transduction Pathway ◽  
Wild Type ◽  
Pathogen Invasion ◽  
Tms2 Gene

Salicylic acid (SA) plays an important signaling role in the resistance of many plants to pathogen invasion. Increases in endogenous SA levels have been associated with the hypersensitive response as well as systemic acquired resistance (SAR). SA also induces the expression of a subset of the pathogenesis-related (PR) genes. However, relatively little is known about the events occurring subsequent to SA accumulation during a resistance response. In order to identify mutations in components of the SA signal transduction pathway, we have developed a genetic screen in Arabidopsis thaliana that utilizes the Agrobacterium tumefaciens tms2 gene as a counter-selectable marker. SA-inducible expression of the tms2 gene from the tobacco PR-1a promoter confers sensitivity to α-naphthalene acetamide (α-NAM), resulting in inhibition of root growth in germinating transgenic Arabidopsis seedlings. Mutants in which root growth is insensitive to α-NAM have been selected from this PR-1a:tms2 transgenic line with the expectation that a subset will lack a regulatory component downstream of SA. The sai1 mutant so identified expressed neither the PR-1a:tms2 transgene nor the endogenous Arabidopsis PR-1, PR-2, and PR-5 genes in response to SA. These genes also were not induced in sai1 by 2,6-dichloroisonicotinic acid (INA) or benzothiadiazole (BTH), two chemical inducers of SAR. As expected of a mutation acting downstream of SA, sai1 plants accumulate SA and its glucoside in response to infection with an avirulent pathogen and are more susceptible to this avirulent pathogen than the wild-type parent. sai1 is allelic to npr1, a previously identified SA-noninducible mutation. The recessive nature of the noninducible sai1 mutation suggests that the wild-type SAI1 gene acts as a positive regulator in the SA signal transduction pathway.

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