scholarly journals RNase Activity Prevents the Growth of a Fungal Pathogen in Tobacco Leaves and Increases upon Induction of Systemic Acquired Resistance with Elicitin

1997 ◽  
Vol 115 (4) ◽  
pp. 1557-1567 ◽  
Author(s):  
E. Galiana ◽  
P. Bonnet ◽  
S. Conrod ◽  
H. Keller ◽  
F. Panabieres ◽  
...  
2019 ◽  
Vol 22 (8) ◽  
pp. 987-991 ◽  
Author(s):  
E. A. Trifonova ◽  
S. M. Ibragimova ◽  
O. A. Volkova ◽  
V. K. Shumny ◽  
A. V. Kochetov

Disease resistance is an important characteristic for each variety of potato, and the search for pathogen resistance markers is one of the primary tasks of plant breeding. Higher plants possess a wide spectrum of enzymes catalyzing the hydrolysis of nucleic acids; it is believed that protection against pathogens is the most probable function of the enzymes. RNases are actively involved in several immune systems of higher plants, for example, systemic acquired resistance (SAR) and genetic silencing, hence RNase activity in plant leaves, as a relatively easily measured parameter, can serve as a good marker for the selection of pathogen resistant varieties. We have analyzed sixteen varieties of potatoes permitted for use on the territory of the Russian Federation and tested the correlation of the level of variety­specifc ribonuclease (RNase) activity with such economically valuable traits as maturity and resistance to viruses, late blight and common scab. In general, the level of RNase activity was variety­specifc, which was confrmed by very small values of average squared error for the majority of tested varieties. We have detected a statistically signifcant positive correlation of RNase activity in potato leaves with increased resistance of varieties to phytopathogenic viruses, a negative correlation with resistance to scab and an absence of a signifcant connection with maturity and resistance to late blight, regardless of the organ affected by the oomycete. Thus, the level of RNase activity in potato leaves can be used as a selective marker for resistance to viruses, while varieties with increased RNase activity should be avoided when selecting resistance to scab.


Genetics ◽  
1998 ◽  
Vol 149 (2) ◽  
pp. 537-548
Author(s):  
Sigrid M Volko ◽  
Thomas Boller ◽  
Frederick M Ausubel

Abstract To identify plant defense components that are important in restricting the growth of virulent pathogens, we screened for Arabidopsis mutants in the accession Columbia (carrying the transgene BGL2-GUS) that display enhanced disease susceptibility to the virulent bacterial pathogen Pseudomonas syringae pv. maculicola (Psm) ES4326. Among six (out of a total of 11 isolated) enhanced disease susceptibility (eds) mutants that were studied in detail, we identified one allele of the previously described npr1/nim1/sai1 mutation, which is affected in mounting a systemic acquired resistance response, one allele of the previously identified EDS5 gene, and four EDS genes that have not been previously described. The six eds mutants studied in detail (npr1-4, eds5-2, eds10-1, eds11-1, eds12-1, and eds13-1) displayed different patterns of enhanced susceptibility to a variety of phytopathogenic bacteria and to the obligate biotrophic fungal pathogen Erysiphe orontii, suggesting that particular EDS genes have pathogen-specific roles in conferring resistance. All six eds mutants retained the ability to mount a hypersensitive response and to restrict the growth of the avirulent strain Psm ES4326/avrRpt2. With the exception of npr1-4, the mutants were able to initiate a systemic acquired resistance (SAR) response, although enhanced growth of Psm ES4326 was still detectable in leaves of SAR-induced plants. The data presented here indicate that eds genes define a variety of components involved in limiting pathogen growth, that many additional EDS genes remain to be discovered, and that direct screens for mutants with altered susceptibility to pathogens are helpful in the dissection of complex pathogen response pathways in plants.


2021 ◽  
Author(s):  
Ryan Lenz ◽  
Katherine Louie ◽  
Kelsey Sondreli ◽  
Stephanie Galanie ◽  
Jin-Gui Chen ◽  
...  

Sphaerulina musiva is an economically and ecologically important fungal pathogen that causes Septoria stem canker and leaf spot disease of Populus species. To bridge the gap between genetic markers and structural barriers previously found to be linked to Septoria (Sphaerulina musiva) canker disease resistance in poplar, we employed hydrophilic interaction liquid chromatography (HILIC) and tandem mass spectrometry (MS/MS) to identify and quantify metabolites involved with signaling and cell wall re-modelling. Fluctuations in signaling molecules, organic acids, amino acids, sterols, phenolics, and saccharides in resistant and susceptible Populus trichocarpa inoculated with Sphaerulina musiva, were observed. The patterns of 222 metabolites in the resistant host implicates systemic acquired resistance (SAR), cell wall apposition, and lignin deposition as modes of resistance to this hemibiotrophic pathogen. This pattern is consistent with the expected response to the biotrophic phase of S. musiva colonization during the first 24 hours post-inoculation. The fungal pathogen metabolized key regulatory signals of SAR, other phenolics, and precursors of lignin biosynthesis which were depleted in the susceptible host. This is the first study to characterize metabolites associated with the response to initial colonization by S. musiva between resistant and susceptible hosts.


2011 ◽  
Vol 101 (10) ◽  
pp. 1202-1208 ◽  
Author(s):  
Jian-Gang Li ◽  
Jing Cao ◽  
Fei-Fei Sun ◽  
Dong-Dong Niu ◽  
Fang Yan ◽  
...  

In a previous study, we isolated a new harpin protein, PopW, from the bacterium Ralstonia solanacearum ZJ3721 that can induce a hypersensitive response in tobacco, Nicotiana tabacum, leaves. In the current study, we demonstrate that, in a greenhouse experiment, PopW induced tobacco-acquired resistance against the Tobacco mosaic virus (TMV) with a biocontrol efficacy of 80.9 to 97.4% at a concentration as low as 25 μg/ml in both PopW-treated and neighboring leaves. The resistance induced by PopW is systemic acquired resistance mediated by salicylic acid, which was certified by the development of resistance being accompanied by the expression of the pathogenesis-related-1 gene (PR1) 8 h after PopW was sprayed onto the tobacco leaves. In addition, hydrogen peroxide began to accumulate 10 h after PopW spraying, peaking at 24 h with a maximum concentration of 1.97 μM/g fresh weight. The activities of phenylalanine ammonia lyase (EC4.3.1.5), polyphenoloxidase (EC1.14.18.1), and peroxidase (EC1.11.1.7) also increased, peaking at different times in the PopW-treated tobacco leaves. PopW also reduced the level of TMV disease in field trials with a biocontrol efficacy of 45.2%. Furthermore, PopW both increased tobacco yield (by 30.4 more than in control plants) and improved tobacco foliar quality, with an increase of 50.2% in the number of first-class tobacco leaves from treated compared with untreated plants. All of these results indicate that the new harpin protein PopW has the potential to be an effective biocontrol agent against TMV in tobacco.


1999 ◽  
Vol 12 (1) ◽  
pp. 53-58 ◽  
Author(s):  
Antonio Molina ◽  
Jörn Görlach ◽  
Sandra Volrath ◽  
John Ryals

Wheat cDNAs that encode proteins PR-1.1 and PR-1.2 were cloned. Deduced amino acid sequences were homologous to those of pathogen-induced, basic PR-1 proteins from plants. Although expression of PR1.1 and PR1.2 genes was induced upon infection with either compatible or incompatible isolates of the fungal pathogen Erysiphe graminis, these genes did not respond to activators of systemic acquired resistance (SAR), such as salicylic acid (SA), benzothiadiazole (BTH), or isonicotinic acid (INA)


2001 ◽  
Vol 25 (2) ◽  
pp. 149-157 ◽  
Author(s):  
Keiko Yoshioka ◽  
Hideo Nakashita ◽  
Daniel F. Klessig ◽  
Isamu Yamaguchi

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