Potato berry bioassay to detect Streptomyces spp. that produce phytotoxic thaxtomin A and cause potato common scab.

A novel strain of Streptomyces (named DS3024) was isolated from a potato field in Michigan in 2006. The taxonomy of the organism was determined by morphology, biochemistry, and genetic analysis. Analysis of the 16S ribosomal RNA gene sequence indicated that the organism was most similar to an isolate of Streptomyces sp., ME02-6979.3a, which is not pathogenic to potato tubers but is distinct from other known pathogenic Streptomyces spp. Strain DS3024 has genes that encode thaxtomin synthetase (txtAB), which is required for pathogenicity and virulence, and tomatinase (tomA), which is a common marker for many pathogenic Streptomyces spp. However, the nec1 gene (associated with virulence in most pathogenic Streptomyces spp.) was not detected. The new strain was capable of growth at pH 4.5, caused necrosis on potato tuber slices, and produced thaxtomin A. In greenhouse experiments, DS3024 caused scab symptoms on potato tubers similar to those caused by Streptomyces scabies on tubers of potato cv. Atlantic, which is scab susceptible. We propose that DS3024 is a new strain of Streptomyces capable of causing common scab on potato tubers. The prevalence of this strain of Streptomyces in potato-producing areas in the north-central United States has not been determined.

Download Full-text

Quantitative relationships among thaxtomin A production, potato scab severity, and fatty acid composition in Streptomyces

Canadian Journal of Microbiology ◽

10.1139/w98-061 ◽

1998 ◽

Vol 44 (8) ◽

pp. 768-776 ◽

Cited By ~ 35

Author(s):

Linda L Kinkel ◽

John H Bowers ◽

Kyoko Shimizu ◽

Eric C Neeno-Eckwall ◽

Janet L Schottel

Keyword(s):

Fatty Acid ◽

Common Scab ◽

Potato Scab ◽

Quantitative Information ◽

Fatty Acid Profiles ◽

Field Isolates ◽

Thaxtomin A ◽

Streptomyces Spp ◽

Potato Common Scab ◽

Fatty Acid Data

Thaxtomin A production in culture, potato common scab severity (percentage of tuber surface infected or number of lesions per tuber), and fatty acid profiles were determined for 78 Streptomyces isolates. Only pathogenic Streptomyces spp. (n = 17) produced thaxtomin A in culture. Thaxtomin A production in culture (µg/mL) was significantly positively correlated with the percentage of tuber surface infected (R = 0.60; p = 0.017) but not with the number of lesions per tuber (R = 0.37; p = 0.17). An increase of 1 µg/mL in thaxtomin A production corresponded to an 11% increase in disease severity (percentage of tuber surface infected). The data indicate that quantitative information on the ability of a particular pathogen isolate or population to produce thaxtomin A may be critical to understanding and predicting the disease potential of that population. Using cluster analysis of fatty acid data, 94% of 67 unknown field isolates grouped with other field isolates having the same pathogenicity (plus or minus).Key words: thaxtomin A, phytotoxin, potato scab.

Download Full-text

Differential Production of the Phytotoxins Thaxtomin A and Concanamycins A and B by Potato Common Scab-causing Streptomyces spp.

Japanese Journal of Phytopathology ◽

10.3186/jjphytopath.64.202 ◽

1998 ◽

Vol 64 (3) ◽

pp. 202-204 ◽

Cited By ~ 22

Author(s):

Masahiro NATSUME ◽

Akiko YAMADA ◽

Nobuya TASHIRO ◽

Hiroshi ABE

Keyword(s):

Common Scab ◽

Thaxtomin A ◽

Streptomyces Spp ◽

Potato Common Scab

Download Full-text

Comparative Genomics of Potato Common Scab-Causing Streptomyces spp. Displaying Varying Virulence

Frontiers in Microbiology ◽

10.3389/fmicb.2021.716522 ◽

2021 ◽

Vol 12 ◽

Author(s):

Cindy Hudec ◽

Adrien Biessy ◽

Amy Novinscak ◽

Renée St-Onge ◽

Simon Lamarre ◽

...

Keyword(s):

Virulence Factors ◽

Prince Edward Island ◽

Common Scab ◽

Potato Production ◽

Biosynthetic Gene Cluster ◽

Economic Losses ◽

Clear Correlation ◽

Thaxtomin A ◽

Streptomyces Spp ◽

Potato Common Scab

Common scab of potato causes important economic losses worldwide following the development of necrotic lesions on tubers. In this study, the genomes of 14 prevalent scab-causing Streptomyces spp. isolated from Prince Edward Island, one of the most important Canadian potato production areas, were sequenced and annotated. Their phylogenomic affiliation was determined, their pan-genome was characterized, and pathogenic determinants involved in their virulence, ranging from weak to aggressive, were compared. 13 out of 14 strains clustered with Streptomyces scabiei, while the last strain clustered with Streptomyces acidiscabies. The toxicogenic and colonization genomic regions were compared, and while some atypical gene organizations were observed, no clear correlation with virulence was observed. The production of the phytotoxin thaxtomin A was also quantified and again, contrary to previous reports in the literature, no clear correlation was found between the amount of thaxtomin A secreted, and the virulence observed. Although no significant differences were observed when comparing the presence/absence of the main virulence factors among the strains of S. scabiei, a distinct profile was observed for S. acidiscabies. Several mutations predicted to affect the functionality of some virulence factors were identified, including one in the bldA gene that correlates with the absence of thaxtomin A production despite the presence of the corresponding biosynthetic gene cluster in S. scabiei LBUM 1485. These novel findings obtained using a large number of scab-causing Streptomyces strains are challenging some assumptions made so far on Streptomyces’ virulence and suggest that other factors, yet to be characterized, are also key contributors.

Download Full-text

Relationship Between the Application of Foliar Chemicals to Reduce Common Scab Disease of Potato and Correlation with Thaxtomin A Toxicity

Plant Disease ◽

10.1094/pdis-05-11-0397 ◽

2012 ◽

Vol 96 (1) ◽

pp. 97-103 ◽

Cited By ~ 10

Author(s):

Robert S. Tegg ◽

Ross Corkrey ◽

Calum R. Wilson

Keyword(s):

Measurement Error ◽

Common Scab ◽

Russet Burbank Potato ◽

Disease Suppression ◽

Tuber Initiation ◽

Strongly Correlated ◽

Symptom Development ◽

Thaxtomin A ◽

Foliar Sprays ◽

Streptomyces Spp

Production of the phytotoxin thaxtomin A by pathogenic Streptomyces spp. is essential for induction of common scab disease in potato. The disease can be significantly reduced by a range of chemicals applied as foliar sprays before tuber initiation. We tested a range of chemicals that had previously demonstrated varying capacities to reduce common scab for both disease suppression and their ability to inhibit thaxtomin A toxicity in both ‘Desiree’ and ‘Russet Burbank’ potato. Our results for disease suppression generally supported previous studies. Our tuber slice assays with thaxtomin A showed a strong correlation between the ability of the chemical to suppress common scab symptom development and the ability of the chemical to inhibit thaxtomin A toxicity. A Bayesian measurement error linear regression model was derived for each cultivar and trial and demonstrated a clear positive relationship between disease and thaxtomin-A-induced necrosis. The relationships obtained were much stronger than would have been obtained without adjustment for measurement error. This demonstrates that disease mitigation using chemical foliar sprays is strongly correlated with the ability of the chemical to inhibit thaxtomin A toxicity, suggesting this mechanism as a key mode of action for understanding this novel disease control strategy.

Download Full-text

Phenazine Production by Pseudomonas sp. LBUM223 Contributes to the Biological Control of Potato Common Scab

Phytopathology ◽

10.1094/phyto-01-13-0022-r ◽

2013 ◽

Vol 103 (10) ◽

pp. 995-1000 ◽

Cited By ~ 39

Author(s):

Tanya Arseneault ◽

Claudia Goyer ◽

Martin Filion

Keyword(s):

Common Scab ◽

Soil Conditions ◽

Pseudomonas Sp ◽

Thaxtomin A ◽

Potato Common Scab ◽

Phenazine Production ◽

Pathogen Populations ◽

The Impact ◽

Important Disease

Common scab of potato is mainly caused by Streptomyces scabies. Currently, no method can efficiently control this economically important disease. We have previously determined that Pseudomonas sp. LBUM223 exhibits antagonistic properties toward S. scabies under in vitro conditions. Inhibition was mainly attributed to phenazine-1-carboxylic acid (PCA) production because an isogenic mutant of LBUM223 (phzC–), not producing PCA, was incapable of significantly reducing S. scabies growth. In order to understand the impact of PCA production by LBUM223 in controlling common scab under soil conditions, pot experiments were performed to determine its effect on (i) reducing scab symptoms development, (ii) S. scabies population dynamics, and (iii) txtA expression in S. scabies, a key gene involved in thaxtomin A biosynthesis and required for pathogenesis. Symptoms were significantly reduced following inoculation with LBUM223 but not its mutant. Surprisingly, pathogen populations increased in the geocaulosphere in the presence of both wild-type and mutant strains of LBUM223; however, significant repression of txtA expression in S. scabies was only observed in the presence of PCA-producing LBUM223, not its mutant. These results suggest that, under soil conditions, PCA production by LBUM223 does not control common scab development by antibiosis but, instead, reduces S. scabies thaxtomin A production in the geocaulosphere, leading to reduced virulence.

Download Full-text

Isolation and Characterization of Plant-Pathogenic Streptomyces Species Associated with Common Scab-Infected Potato Tubers in Newfoundland

Phytopathology ◽

10.1094/phyto-05-15-0125-r ◽

2016 ◽

Vol 106 (2) ◽

pp. 123-131 ◽

Cited By ~ 15

Author(s):

Joanna K. Fyans ◽

Luke Bown ◽

Dawn R. D. Bignell

Keyword(s):

Common Scab ◽

Virulence Gene ◽

Potato Scab ◽

Potato Tubers ◽

Streptomyces Species ◽

Genus Streptomyces ◽

Thaxtomin A ◽

Streptomyces Spp ◽

Putative Virulence Gene ◽

Isolation And Characterization

Potato common scab (CS) is an economically important crop disease that is caused by several members of the genus Streptomyces. In this study, we characterized the plant-pathogenic Streptomyces spp. associated with CS-infected potato tubers harvested in Newfoundland, Canada. A total of 17 pathogenic Streptomyces isolates were recovered from potato scab lesions, of which eight were determined to be most similar to the known CS pathogen S. europaeiscabiei. All eight S. europaeiscabiei isolates were found to produce the thaxtomin A phytotoxin and to harbor the nec1 virulence gene, and most also carry the putative virulence gene tomA. The remaining isolates appear to be novel pathogenic species that do not produce thaxtomin A, and only two of these isolates were determined to harbor the nec1 or tomA genes. Of the non-thaxtomin-producing isolates, strain 11-1-2 was shown to exhibit a severe pathogenic phenotype against different plant hosts and to produce a novel, secreted phytotoxic substance. This is the first report documenting the plant-pathogenic Streptomyces spp. associated with CS disease in Newfoundland. Furthermore, our findings provide further evidence that phytotoxins other than thaxtomin A may also contribute to the development of CS by Streptomyces spp.

Download Full-text

Microbial Communities Associated with Potato Common Scab-Suppressive Soil Determined by Pyrosequencing Analyses

Plant Disease ◽

10.1094/pdis-07-11-0571 ◽

2012 ◽

Vol 96 (5) ◽

pp. 718-725 ◽

Cited By ~ 97

Author(s):

Noah Rosenzweig ◽

James M. Tiedje ◽

John F. Quensen ◽

Qingxiao Meng ◽

Jianjun J. Hao

Keyword(s):

Microbial Communities ◽

Common Scab ◽

Disease Suppression ◽

Rrna Gene ◽

Suppressive Soil ◽

Streptomyces Spp ◽

Potato Common Scab ◽

Order Of Magnitude ◽

Disease Suppressive Soil ◽

Conducive Soil

Potato common scab, caused by Streptomyces spp., is an annual production problem for potato growers, and not effectively controlled by current methods. A field with naturally occurring common scab suppression has been identified in Michigan, and confirmed to have a biological basis for this disease suppression. This field and an adjacent scab nursery conducive to disease were studied using pyrosequencing to compare the two microbial communities. Total DNA was extracted from both the disease-conducive and -suppressive soils. A phylogenetically taxon-informative region of the 16S rRNA gene was used to establish operational taxonomic units (OTUs) to characterize bacterial community richness and diversity. In total, 1,124 OTUs were detected and 565 OTUs (10% dissimilarity) were identified in disease-conducive soil and 859 in disease-suppressive soil, including 300 shared both between sites. Common phyla based on relative sequence abundance were Acidobacteria, Proteobacteria, and Firmicutes. Sequences of Lysobacter were found in significantly higher numbers in the disease-suppressive soil, as were sequences of group 4 and group 6 Acidobacteria. The relative abundance of sequences identified as the genus Bacillus was significantly higher by an order of magnitude in the disease-conducive soil.

Download Full-text

Repeated Applications of a Nonpathogenic Streptomyces Strain Enhance Development of Suppressiveness to Potato Common Scab

Plant Disease ◽

10.1094/pdis-07-16-1020-re ◽

2017 ◽

Vol 101 (1) ◽

pp. 224-232 ◽

Cited By ~ 3

Author(s):

Lea H. Hiltunen ◽

Jani Kelloniemi ◽

Jari P. T. Valkonen

Keyword(s):

Common Scab ◽

Disease Incidence ◽

Potato Cultivar ◽

Disease Suppression ◽

Streptomyces Strain ◽

Streptomyces Spp ◽

Potato Common Scab ◽

Repeated Applications ◽

Disease Pressure

Potato common scab caused by several Streptomyces spp. is an important disease with no effective methods of control. Suppressiveness against common scab can develop in soil as a result of long-term potato monoculture and has been associated with nonpathogenic Streptomyces spp. To determine whether the development of scab suppressiveness could be enhanced, the effect of repeated applications of an antagonistic Streptomyces strain on common scab was investigated in a long-term field trial over 5 years. Streptomyces strain 272 applied annually at planting consistently suppressed development of common scab symptoms. On scab-susceptible potato cultivar Bintje, strain 272 reduced disease severity, on average, by 43%; whereas, on the scab-tolerant Nicola, the strain reduced both disease incidence and severity by 43 and 59%, respectively. Regardless of disease pressure, the combined use of strain 272 and the tolerant cultivar reduced the scab coverage to a negligible level. After a single application of strain 272, efficient disease suppression did not persist in the soil to the following growing season. However, when strain 272 was applied in three or more consecutive years, the soil remained suppressive to scab for at least 2 years beyond the last application, suggesting that, with repeated applications, it may be possible to enhance development of scab suppression in soil.

Download Full-text

Rice Bran Amendment Suppresses Potato Common Scab by Increasing Antagonistic Bacterial Community Levels in the Rhizosphere

Phytopathology ◽

10.1094/phyto-12-15-0322-r ◽

2016 ◽

Vol 106 (7) ◽

pp. 719-728 ◽

Cited By ~ 13

Author(s):

Tsuyoshi Tomihama ◽

Yatsuka Nishi ◽

Kiyofumi Mori ◽

Tsukasa Shirao ◽

Toshiya Iida ◽

...

Keyword(s):

Rice Bran ◽

Common Scab ◽

Cultural Practices ◽

Potato Production ◽

Amplicon Sequencing ◽

Underlying Disease ◽

Antagonistic Activity ◽

Disease Suppression ◽

Streptomyces Spp ◽

Potato Common Scab

Potato common scab (PCS), caused by pathogenic Streptomyces spp., is a serious disease in potato production worldwide. Cultural practices, such as optimizing the soil pH and irrigation, are recommended but it is often difficult to establish stable disease reductions using these methods. Traditionally, local farmers in southwest Japan have amended soils with rice bran (RB) to suppress PCS. However, the scientific mechanism underlying disease suppression by RB has not been elucidated. The present study showed that RB amendment reduced PCS by repressing the pathogenic Streptomyces population in young tubers. Amplicon sequencing analyses of 16S ribosomal RNA genes from the rhizosphere microbiome revealed that RB amendment dramatically changed bacterial composition and led to an increase in the relative abundance of gram-positive bacteria such as Streptomyces spp., and this was negatively correlated with PCS disease severity. Most actinomycete isolates derived from the RB-amended soil showed antagonistic activity against pathogenic Streptomyces scabiei and S. turgidiscabies on R2A medium. Some of the Streptomyces isolates suppressed PCS when they were inoculated onto potato plants in a field experiment. These results suggest that RB amendment increases the levels of antagonistic bacteria against PCS pathogens in the potato rhizosphere.

Download Full-text