Designing a crop rotation strategy to manage Streptomyces scabies causing potato scab in north India

2020 ◽  
Vol 168 (7-8) ◽  
pp. 469-477
Author(s):  
Mandeep Singh Hunjan ◽  
Hardeep Singh Sabhikhi
Keyword(s):  
Crop Rotation ◽  
Potato Scab ◽  
Streptomyces Scabies ◽  
North India ◽  
Rotation Strategy

scholarly journals Effect of Nitrogen Fertilizer on Soil CO2 Emission Depends on Crop Rotation Strategy

2020 ◽  
Vol 12 (13) ◽  
pp. 5271
Author(s):  
Dejie Kong ◽  
Nana Liu ◽  
Chengjie Ren ◽  
Huiying Li ◽  
Weiyu Wang ◽  
...  
Keyword(s):  
Crop Rotation ◽  
Co2 Emission ◽  
Management Practices ◽  
N Fertilizer ◽  
Emission Rates ◽  
Fertilizer Management ◽  
Soil Co2 ◽  
Soil Co2 Emission ◽  
The Impact ◽  
Rotation Strategy

Developing environmentally friendly and sustainable nitrogen (N) fertilizer management strategies is crucial in mitigating carbon dioxide (CO2) emission from soil. How N fertilizer management practices influence soil CO2 emission rates under different crop rotations remains unclear. The aim of this study was to assess the impact on soil CO2 emission and soil physicochemical properties of three N fertilizer treatments including traditional rate (TF), optimized rate (0.8TF), and no fertilizer (NF) under three different crop rotation treatments: wheat-fallow (WF), wheat-soybean (WS), and wheat-maize (WM) over two years in a field experiment in northwest China. The rates were 5.51, 5.60, and 5.97 μmol·m−2·s−1 of mean soil CO2 emission under the TF, 0.8TF, and NF treatments, respectively. Mean soil CO2 emission rates were 21.33 and 26.99% higher under the WM rotation compared with the WF and WS rotations, respectively. The WS rotation showed higher soil nutrient content and lower soil CO2 emissions, and reduced fertilizer application. Importantly, soil organic carbon (SOC) concentration in the topsoil can be maximized by including either a summer legume or a summer maize crop in winter wheat rotations, and by applying N fertilizer at the optimal rate. This may be particularly beneficial in the dryland cropping systems of northern China.

scholarly journals Hopanoids Are Not Essential for Growth of Streptomyces scabies 87-22

2009 ◽  
Vol 191 (16) ◽  
pp. 5216-5223 ◽  
Author(s):  
Ryan F. Seipke ◽  
Rosemary Loria
Keyword(s):  
Cell Function ◽  
Normal Growth ◽  
Potato Scab ◽  
Biosynthetic Gene Cluster ◽  
Streptomyces Scabies ◽  
Morphological Development ◽  
Bacterial Physiology ◽  
Aerial Growth ◽  
Mutant Strains ◽  
And Oxidative Stress

ABSTRACT Hopanoids are triterpenoic, pentacyclic compounds that are structurally similar to sterols, which are required for normal cell function in eukaryotes. Hopanoids are thought to be an important component of bacterial cell membranes because they control membrane fluidity and diminish passive diffusion of ions, and a few taxons modulate their hopanoid content in response to environmental stimuli. However, to our knowledge, mutational studies to assess the importance of hopanoids in bacterial physiology have never been performed. Genome sequencing of the potato scab pathogen, Streptomyces scabies 87-22, revealed a hopanoid biosynthetic gene cluster (HBGC) that is predicted to synthesize hopene and aminotrihydroxybacteriohopane products. Hopene was produced by fully sporulated cultures of S. scabies on solid ISP4 (International Streptomyces Project 4) medium as well as by submerged mycelia grown in liquid minimal medium. The elongated hopanoid aminotrihydroxybacteriohopane was not detected under either growth condition. Transcription of the S. scabies HBGC was upregulated during aerial growth, which suggests a link between hopanoid production and morphological development. Functional analysis of the S. scabies Δhop615-1 and Δhop615-7 mutant strains, the first hopanoid mutants created in any bacterial taxon, revealed that hopanoids are not required for normal growth or for tolerance of ethanol, osmotic and oxidative stress, high temperature, or low pH. This suggests that hopanoids are not essential for normal streptomycete physiology.

Competition and antibiosis in the biological control of potato scab

2001 ◽  
Vol 47 (4) ◽  
pp. 332-340 ◽  
Author(s):  
Eric C Neeno-Eckwall ◽  
Linda L Kinkel ◽  
Janet L Schottel
Keyword(s):  
Biological Control ◽  
Population Density ◽  
Potato Scab ◽  
Antibiotic Activity ◽  
Streptomyces Scabies ◽  
Population Densities ◽  
Streptomyces Diastatochromogenes ◽  
Greenhouse Assay ◽  
Spontaneous Mutants

Nonpathogenic, antibiotic-producing streptomycetes have been shown to reduce potato scab when added to disease-conducive soil. Spontaneous mutants of the pathogenic Streptomyces scabies RB4 that are resistant to at least one antibiotic activity produced by the nonpathogenic suppressive isolates Streptomyces diastatochromogenes strain PonSSII and S. scabies PonR have been isolated. To determine the importance of antibiosis in this biocontrol system, these mutants were investigated for their ability to cause disease in the presence of the two pathogen antagonists in a greenhouse assay. Disease caused by one of the mutant strains was reduced in the presence of both suppressive isolates, whereas disease caused by the other five mutants was not significantly reduced by either suppressive strain. In addition, a nonpathogenic mutant of S. scabies RB4 was isolated, which produced no detectable in vitro antibiotic activity and reduced disease caused by its pathogenic parent strain when the pathogen and mutant were coinoculated into soil. Population densities of the pathogen were consistently lower than those of the suppressive strains when individual strains were inoculated into soil. When a pathogen was coinoculated with a suppressive strain, the total streptomycete population density in the pot was always less than that observed when the suppressive isolate was inoculated alone. When the pathogens were inoculated individually into soil, a positive correlation was seen between population density and disease severity. In coinoculation experiments with pathogen and suppressive strains, higher total streptomycete population densities were correlated with lower amounts of disease.Key words: Streptomyces scabies, biological control, antibiotic resistance, potato scab disease.

scholarly journals Production and regulation of potato-scab-inducing phytotoxins by Streptomyces scabies

1993 ◽  
Vol 139 (7) ◽  
pp. 1579-1586 ◽  
Author(s):  
M. J. Babcock ◽  
E. C. Eckwall ◽  
J. L. Schottel
Keyword(s):  
Potato Scab ◽  
Streptomyces Scabies
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