Role of Phenylalanine Ammonia Lyase and Polyphenol Oxidase in Host Resistance to Bacterial Wilt of Tomato

Pectobacterium atrosepticum, P. carotovorum subsp. brasiliensis, and Dickeya spp. cause soft rot of potato (Solanum tuberosum) worldwide. Plants respond to bacterial invasion by activating defense responses associated with accumulation of several enzymes and inhibitors, which prevent pathogen infection. This study focused on the role of polyphenol oxidase (PPO), peroxidase (POD), phenylalanine ammonia lyase (PAL), chlorogenic acid, and total soluble phenols in imparting resistance to soft rot pathogens. Seven and 11 varieties grown by farmers in South Africa and Zimbabwe, respectively, were used in the study. The results showed significantly higher (P < 0.001) enzyme activity of PPO and PAL as well as higher concentrations of chlorogenic acid and total soluble phenols in Vanderplank, Pentland Dell, M69/11, Romano, M59/20, and MondialZw. PAL activity increased significantly with time in all varieties, and the highest activity was recorded 8 h after cutting. The resistance of the varieties was correlated with high PPO and PAL enzyme activity as well as increased concentrations of chlorogenic acid and total soluble phenols. PPO, POD, and PAL activities increased significantly in wounded and inoculated tubers. These findings show that PAL, PPO, POD, chlorogenic acid, and total soluble phenols play a role in imparting resistance to potato soft rot infection.

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Role of hydrogen peroxide and ascorbate-glutathione pathway in host resistance to bacterial wilt of eggplant

Russian Journal of Plant Physiology ◽

10.1134/s1021443717030049 ◽

2017 ◽

Vol 64 (3) ◽

pp. 375-385 ◽

Cited By ~ 1

Author(s):

P. Avinash ◽

S. Umesha ◽

S. Marahel

Keyword(s):

Hydrogen Peroxide ◽

Bacterial Wilt ◽

Host Resistance ◽

Glutathione Pathway

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BROWNING OF LITCHI FRUIT PERICARP: ROLE OF POLYPHENOL OXIDASE, PEROXIDASE, PHENYLALANINE AMMONIA LYASE AND EFFECT OF GAMMA RADIATION*

Journal of Food Biochemistry ◽

10.1111/j.1745-4514.2011.00572.x ◽

2011 ◽

Vol 36 (5) ◽

pp. 604-612 ◽

Cited By ~ 16

Author(s):

BIBHUTI BHUSAN MISHRA ◽

SANJEEV KUMAR ◽

SURBHI WADHAWAN ◽

SACHIN N. HAJARE ◽

SUDHANSHU SAXENA ◽

...

Keyword(s):

Gamma Radiation ◽

Polyphenol Oxidase ◽

Phenylalanine Ammonia Lyase ◽

Fruit Pericarp ◽

Litchi Fruit

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Faculty Opinions recommendation of An important role of prostanoid receptor EP2 in host resistance to Mycobacterium tuberculosis infection in mice.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.725356631.793504122 ◽

2015 ◽

Author(s):

Padmini Salgame ◽

Archana Gopalakrishnan

Keyword(s):

Mycobacterium Tuberculosis ◽

Host Resistance ◽

Tuberculosis Infection ◽

Mycobacterium Tuberculosis Infection ◽

Prostanoid Receptor

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Different Sequevars of Ralstonia pseudosolanacearum Causing Bacterial Wilt of Bidens pilosa in China

Plant Disease ◽

10.1094/pdis-12-19-2738-sc ◽

2020 ◽

Vol 104 (11) ◽

pp. 2768-2773

Author(s):

Yonglin He ◽

Yixue Mo ◽

Dehong Zheng ◽

Qiqin Li ◽

Wei Lin ◽

...

Keyword(s):

Arachis Hypogaea ◽

Bacterial Wilt ◽

Geographical Origin ◽

Bidens Pilosa ◽

Invasive Weed ◽

High Virulence ◽

Race 1 ◽

Ralstonia Pseudosolanacearum ◽

Phylotype I

Bidens pilosa is an invasive weed that threatens the growth of crops and biodiversity in China. In 2017, suspected bacterial wilt of B. pilosa was discovered in Qinzhou and Beihai, Guangxi, China. A variety of weeds are considered as reservoirs harboring bacterial wilt pathogens, but most do not show obvious symptoms in the field. Identifying the classification status of the B. pilosa bacterial wilt pathogen and exploring its geographical origin might be helpful for clarifying the role of weeds in the circulation of the disease. Phylotyping, sequevar analysis, and cross inoculation of pathogens isolated from B. pilosa and nearby peanut (Arachis hypogaea), balsam gourd (Momordica charantia), and eucalyptus (Eucalyptus robusta) plants were carried out. Three isolates of B. pilosa (Bp01, Bp02, and Bp03) were identified as Ralstonia pseudosolanacearum, race 1, biovar 3, and phylotype I, and belonged to sequevars 17 and 44, and an unknown sequevar. The sequevars isolated from B. pilosa were not completely consistent with those of the nearby hosts, and the virulence of these isolates differed when cross inoculated. The Bp03 sequevar was different from peanut isolate sequevars in the same field and was not identical to any previously designated sequevars. The isolates from B. pilosa and other nearby hosts displayed low or no virulence toward their cross hosts (with wilt incidences less than 33.33%). An exception to this was the isolates from B. pilosa, which displayed high virulence toward eucalyptus (with a wilt incidence of 70.00 to 100.00%). This is the first report of different sequevars of R. pseudosolanacearum causing typical bacterial wilt symptoms in B. pilosa in the field.

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Ralstonia solanacearum Needs Motility for Invasive Virulence on Tomato

Journal of Bacteriology ◽

10.1128/jb.183.12.3597-3605.2001 ◽

2001 ◽

Vol 183 (12) ◽

pp. 3597-3605 ◽

Cited By ~ 201

Author(s):

Julie Tans-Kersten ◽

Huayu Huang ◽

Caitilyn Allen

Keyword(s):

Bacterial Wilt ◽

Ralstonia Solanacearum ◽

Soft Agar ◽

Cell Protein ◽

In Planta ◽

Tomato Plants ◽

Bacterial Wilt Disease ◽

Virulence Assay ◽

Flagellar Filament

ABSTRACT Ralstonia solanacearum, a widely distributed and economically important plant pathogen, invades the roots of diverse plant hosts from the soil and aggressively colonizes the xylem vessels, causing a lethal wilting known as bacterial wilt disease. By examining bacteria from the xylem vessels of infected plants, we found thatR. solanacearum is essentially nonmotile in planta, although it can be highly motile in culture. To determine the role of pathogen motility in this disease, we cloned, characterized, and mutated two genes in the R. solanacearum flagellar biosynthetic pathway. The genes for flagellin, the subunit of the flagellar filament (fliC), and for the flagellar motor switch protein (fliM) were isolated based on their resemblance to these proteins in other bacteria. As is typical for flagellins, the predicted FliC protein had well-conserved N- and C-terminal regions, separated by a divergent central domain. The predicted R. solanacearum FliM closely resembled motor switch proteins from other proteobacteria. Chromosomal mutants lackingfliC or fliM were created by replacing the genes with marked interrupted constructs. Since fliM is embedded in the fliLMNOPQR operon, the aphAcassette was used to make a nonpolar fliM mutation. Both mutants were completely nonmotile on soft agar plates, in minimal broth, and in tomato plants. The fliC mutant lacked flagella altogether; moreover, sheared-cell protein preparations from the fliC mutant lacked a 30-kDa band corresponding to flagellin. The fliM mutant was usually aflagellate, but about 10% of cells had abnormal truncated flagella. In a biologically representative soil-soak inoculation virulence assay, both nonmotile mutants were significantly reduced in the ability to cause disease on tomato plants. However, the fliC mutant had wild-type virulence when it was inoculated directly onto cut tomato petioles, an inoculation method that did not require bacteria to enter the intact host from the soil. These results suggest that swimming motility makes its most important contribution to bacterial wilt virulence in the early stages of host plant invasion and colonization.

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