Zoospore production in Pythium spinosum

1993 ◽  
Vol 97 (12) ◽  
pp. 1495-1498 ◽  
Author(s):  
W.J. Botha
Keyword(s):  
Zoospore Production

Zoospore Production Biology of Pythiaceous Plant Pathogens

2013 ◽  
Vol 162 (2) ◽  
pp. 69-80 ◽  
Author(s):  
Michael Pistininzi ◽  
Edward Weiss ◽  
Lauren Achtemeier ◽  
Chuanxue Hong
Keyword(s):  
Plant Pathogens ◽  
Zoospore Production ◽  
Production Biology

scholarly journals Selection of Biocontrol Agents of Pink Rot Based on Efficacy and Growth Kinetics Index Rankings

Plant Disease ◽  
2011 ◽  
Vol 95 (1) ◽  
pp. 24-30 ◽  
Author(s):  
Tugba Adiyaman ◽  
David A. Schisler ◽  
Patricia J. Slininger ◽  
Jennifer M. Sloan ◽  
Mark A. Jackson ◽  
...  
Keyword(s):  
Agricultural Soils ◽  
Oxygen Depletion ◽  
Bacterial Strains ◽  
Γ Irradiation ◽  
Commercial Development ◽  
Biocontrol Efficacy ◽  
Pink Rot ◽  
Production Values ◽  
Zoospore Production ◽  
Significant Difference

The microbiota of 84 different agricultural soils were transferred to separate samples of a γ irradiation-sterilized field soil enriched with potato periderm, and the resulting soils were assayed for biological suppressiveness to Phytophthora erythroseptica and their effect on zoospore production. The 13 most suppressive soil samples, which reduced zoospore production by 14 to 93% and disease severity on tubers by 6 to 21%, were used to isolate 279 organisms. Fourteen strains that reduce pink rot infections in preliminary tests were selected for further study. Six bacterial strains that reduced the severity of disease (P ≤ 0.05, Fischer's protected least significant difference) in subsequent tests were identified as Bacillus simplex (three strains), Pantoea agglomerans, Pseudomonas koreensis, and P. lini. Relative performance indices (RPIs) for biocontrol efficacy and for each of four kinetic parameters, including total colony-forming units (CFUmax), biomass production values (DWmax), cell production after 8 h (OD8), and time of recovery from oxygen depletion (DT) were calculated for each strain. Overall RPIEff,Kin values for each strain then were calculated using strain RPI values for both efficacy (RPIEff) and kinetics (RPIKin). Strains with the highest RPIEff,Kin possess the best biocontrol efficacy of the strains tested and liquid culture growth characteristics that suggest commercial development potential.

scholarly journals Mutations in ORP1 Conferring Oxathiapiprolin Resistance Confirmed by Genome Editing using CRISPR/Cas9 in Phytophthora capsici and P. sojae

2018 ◽  
Vol 108 (12) ◽  
pp. 1412-1419 ◽  
Author(s):  
Jianqiang Miao ◽  
Yuandong Chi ◽  
Dong Lin ◽  
Brett M. Tyler ◽  
Xili Liu
Keyword(s):  
Binding Protein ◽  
Phytophthora Capsici ◽  
Control Plant ◽  
Point Mutations ◽  
Wild Type ◽  
Oxysterol Binding Protein ◽  
Type Isolate ◽  
Phytophthora Spp ◽  
Zoospore Production ◽  
Wild Type Parent

Oxathiapiprolin is a novel fungicide that was recently registered in a number of countries to control plant-pathogenic oomycetes such as Phytophthora capsici. In our previous study, point mutations G770V and G839W in oxysterol binding protein-related protein 1 (ORP1) were detected in oxathiapiprolin-resistant P. capsici isolates (PcORP1). Here, we used the CRISPR/Cas9 system to verify the effects of these two point mutations on P. capsici phenotypes. Transformants containing heterozygous G770V and G839W mutations in PcORP1 showed high levels of oxathiapiprolin resistance. The G770V transformants showed otherwise similar phenotypes compared with the wild-type isolate BYA5, including sporangia and zoospore production, cyst germination, and pathogenicity. However, two independent transformants with heterozygous G839W mutations in PcORP1 could not produce sporangia. Three transformants with an unexpected point mutation in PcORP1 (ΔN837) showed high oxathiapiprolin resistance, and either similar or significantly reduced fitness compared with BYA5. The same deletion (ΔN837) was confirmed to confer oxathiapiprolin resistance in P. sojae by using CRISPR/Cas9. These homozygous P. sojae mutants also showed either similar or strongly reduced fitness compared with the wild-type parent isolate P6497. These results improve our understanding of oxathiapiprolin resistance in Phytophthora spp., and will be useful for the development of novel oxysterol-binding protein homolog inhibitor fungicides.

scholarly journals Effect of photosensitisers on growth and morphology of Phytophthora citrophthora coupled with leaf bioassays in pear seedlings

2020 ◽  
Vol 56 (No. 2) ◽  
pp. 74-82 ◽  
Author(s):  
Antonios Zambounis ◽  
Oksana Sytar ◽  
Dimitris Valasiadis ◽  
Zoe Hilioti
Keyword(s):  
Mycelial Growth ◽  
Biological Effects ◽  
Dry Weight ◽  
Colony Growth ◽  
Inhibitory Effect ◽  
Economic Losses ◽  
Inhibitory Effects ◽  
Phytophthora Citrophthora ◽  
Irregular Shapes ◽  
Zoospore Production

The phytopathogenic oomycetes of the genus Phytophthora cause devastating economic losses worldwide.<br />Naphthodianthrone compounds, present in plant extracts of buckwheat and Saint John’s wort act as photosensitiser<br />agents and exhibit antimicrobial activity against a number of pathogens. In this study, we investigated the potential<br />inhibitory effects of fagopyrin and hypericin on Phytophthora citrophthora (R.E. Sm. &amp; E.H. Sm.) Leonian 1906, the<br />main causal agent of rot diseases in deciduous trees. Fagopyrin had the highest inhibitory effect in the colony growth<br />at a concentration of 2% of a stock solution (3 mg/mL), inducing clubbed hyphae with round tips. Notably, hypericin<br />also inhibited the radial colony growth and increased the hyphal branching at the subapical region, while also promoting<br />the formation of enlarged cells with irregular shapes growing collectively as biofilm-like structures. In terms of the<br />mycelial dry weight, although both photosensitisers had considerable inhibitory effects, the fagopyrin treatment was<br />most effective. Leaf bioassays showed that under dark conditions the photosensitiser pre-treated zoospores formed a<br />dense, but aberrant, mycelial growth with penetration defects. In contrast, when the zoospore production was performed<br />under light conditions, the zoospores failed to cause necrotic lesions and penetration events implying that their<br />virulence was impaired. These findings shed light on the biological effects of fagopyrin and hypericin in the regulation<br />of the mycelial growth, morphology and pathogenicity of P. citrophthora.

scholarly journals Effects of Gypsum on Zoospores and Sporangia of Phytophthora cinnamomi in Field Soil

Plant Disease ◽  
2000 ◽  
Vol 84 (6) ◽  
pp. 617-621 ◽  
Author(s):  
B. J. Messenger ◽  
J. A. Menge ◽  
E. Pond
Keyword(s):  
Calcium Sulfate ◽  
Phytophthora Cinnamomi ◽  
Calcium Nitrate ◽  
Passive Movement ◽  
Field Soil ◽  
Soil Extracts ◽  
Zoospore Production ◽  
Colony Forming Units ◽  
Amended Soil

Sporangial production of Phytophthora cinnamomi buried in gypsum-amended avocado soil for 2 days was reduced by as much as 74% in greenhouse trials. P. cinnamomi sporangial volume was reduced an average of 64% in gypsum-amended soil. Soil extracts from gypsum-amended soil reduced in vitro sporangial production and volume. Irrigation with gypsum solutions of buried mycelium in unamended soil also reduced sporangial production and volume. Zoospore production and colony-forming units of P. cinnamomi were reduced in soil amended with calcium sulfate, calcium nitrate, or calcium carbonate. Zoospore encystment or passive movement through soil was not significantly affected by gypsum soil amendments.

Inhibitory effects of the natural product esculetin on Phytophthora capsici and its possible mechanism

Plant Disease ◽  
2020 ◽  
Author(s):  
Bi Wang ◽  
Pirui Li ◽  
Shu Xu ◽  
Lanying Liu ◽  
Yannan Xu ◽  
...  
Keyword(s):  
Natural Product ◽  
Phytophthora Capsici ◽  
Membrane Damage ◽  
Inhibitory Effects ◽  
Baseline Sensitivity ◽  
Cell Membrane Damage ◽  
Zoospore Production ◽  
Geographical Regions ◽  
Dna And Protein Synthesis ◽  
Median Effective Concentration

Esculetin is an important plant-derived natural product that has multiple bioactivities and applications. Phytophthora capsici is a notorious plant pathogen capable of infecting a broad range of hosts. In this study, we evaluated the antifungal activity of esculetin against P. capsici. The baseline sensitivity of P. capsici to esculetin was established using 108 isolates collected from various geographical regions in the Jiangsu and Shandong Provinces of China. The median effective concentration (EC50) values for esculetin ranged from 2.08 to 16.46 μg/mL, with a mean of 6.87 ± 2.70 μg/mL, and were normally distributed. Furthermore, both zoospore production and germination were also strongly inhibited by esculetin. Importantly, esculetin exhibited protective as well as curative activities against P. capsici on tomato, and was capable of restricting the early infection of P. capsici on Nicotiana benthamiana. We found that the esculetin treatment led to cell membrane damage of P. capsici, as revealed by morphological observations and measurements of relative conductivity and malondialdehyde (MDA). Finally, our results also suggested esculetin may adversely affect P. capsici by inhibiting its DNA and protein synthesis. These findings will contribute to a broader evaluation of using esculetin to control diseases caused by P. capsici and towards a better understanding of its mode of action as a potential fungicide.

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