scholarly journals Identification and Biological Characteristic Analysis of Pythium aristosporum Causing Rice Seedling Blight in Northeast China

2020 ◽  
Keyword(s):  
Northeast China ◽  
Rice Seedling ◽  
Biological Characteristic ◽  
Seedling Blight ◽  
Characteristic Analysis

Abstract The authors have requested that this preprint be withdrawn due to author disagreement.

scholarly journals Identification and Biological Characteristic Analysis of Pythium aristosporum Causing Rice Seedling Blight in Northeast China

2020 ◽  
Author(s):  
Jinxin Liu ◽  
Chuzheng Xu ◽  
Wenbo Han ◽  
Yonggang Li
Keyword(s):  
Northeast China ◽  
Ipomoea Batatas ◽  
Rice Seedling ◽  
Biological Characteristics ◽  
Control Measures ◽  
Practical Significance ◽  
Targeted Prevention ◽  
Seedling Blight ◽  
Characteristic Analysis ◽  
Wide Range

Abstract Background: Rice seedling blight caused by diverse pathogenic microorganism occurs worldwide, and it is currently the most important seedling disease affecting rice production in Northeast China. Understanding the biological characteristics, host range, and fungicide sensitivity of pathogens causing rice seedling blight has important theoretical and practical significance for further exploring occurrence of the disease and for making targeted prevention and control measures.Results: 10 isolates of Pythium spp. were obtained from rice seedling blight, according to Koch’s postulates, in Heilongjiang Province, China. Based on morphology, molecular biology, and phylogenetic tree analyses, the obtained fungal isolates were identified as P. aristosporum. The biological characteristics of P. aristosporum showed that the optimum fermentation conditions were as follows: temperature, 25°C; initial pH, 6; photoperiod, 24 h light; and carbon and nitrogen sources, starch and glycine, respectively. P. aristosporum causing rice seedling blight had a wide range of hosts and could infect tomato (Solanum lycopersicum), carrot (Daucus carota L.), sweetpotato (Ipomoea batatas), cucumber (Cucumis sativus L.), and zucchini (Cucurbita pepo L.), as well as seedlings of broad bean (Vicia faba L.), red bean (Vigna angularis), snailflower (Lablab purpureus (Linn.)Sweet), soybean (Glycine max), mung bean (Vigna radiata), kidney bean (Phaseolus vulgaris), and hyacinth bean (Dolichos lablab L.); however, it could not infect cabbage (Brassica oleracea L.) and maize (Zea mays L.) seedlings. We also evaluated P. aristosporum sensitivity to five commonly used fungicides and found that fludioxonil (EC50 = 0.0731 μg/ml) was the most effective against P. aristosporum.Conclusion: To our knowledge, this is the first report of P. aristosporum causing rice seedling blight in China. Fludioxonil is a relatively sensitive chemical fungicide against P. aristosporum. P. aristosporum causing rice seedling blight has a good environmental adaptability and a wide range of hosts, which poses a great threat to rice seedling production. Occurrence of the new disease caused by P. aristosporum should give full consideration for the use of proper disease management to protect rice.

scholarly journals Population Structure and Genetic Diversity of Fungi Causing Rice Seedling Blight in Northeast China Based on Microsatellite Markers

Plant Disease ◽  
2020 ◽  
Vol 104 (3) ◽  
pp. 868-874
Author(s):  
J. X. Liu ◽  
Y. N. Cai ◽  
W. Y. Jiang ◽  
Y. G. Li ◽  
Q. F. Zhang ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Northeast China ◽  
Management Strategies ◽  
Geographical Location ◽  
Rice Seedling ◽  
Fungal Species ◽  
Seedling Blight ◽  
Rice Varieties ◽  
Simple Sequence Repeat Analysis

Rice seedling blight, which is caused by diverse pathogenic microorganisms, occurs worldwide and is the most important seedling disease affecting rice production in Northeast China. To further characterize the population structure and genetic diversity of the fungi responsible for rice seedling blight in Northeast China, 225 fungal strains were isolated from diseased rice seedlings collected from various rice-producing areas. The isolated strains included Fusarium oxysporum (48.0%), F. verticillioides (11.6%), F. tricinctum (8.0%), F. redolens (6.7%), F. equiseti (6.2%), F. solani (6.2%), Rhizoctonia solani (6.7%), Alternaria alternata (4.0%), and Curvularia coatesiae (2.7%). F. oxysporum was the dominant fungal species causing rice seedling blight, with most isolates exhibiting moderate pathogenicity. Moreover, to our knowledge, this is the first study to identify A. alternata and C. coatesiae as causal agents of rice seedling blight in Northeast China. None of the F. oxysporum isolates were sensitive to 10 μg/ml of carbendazim, implying that carbendazim is ineffective for controlling rice seedling blight in Northeast China. The F. oxysporum isolates were divided into nine groups based on a simple sequence repeat analysis involving 14 primer pairs. In addition, an analysis of molecular variance revealed a significant correlation between the F. oxysporum population and geographical location, which had a significant effect on the differentiation of the dominant isolate population. The results of this study provide insights into the genetic diversity of F. oxysporum strains causing rice seedling blight and may be useful for selecting isolates to screen for disease-resistant rice varieties, evaluating fungicide efficacy, and developing effective disease management strategies.

scholarly journals Unraveling the Metabolite Signature of Endophytic Bacillus velezensis Strain Showing Defense Response Towards Fusarium oxysporum

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 683
Author(s):  
Yang Cao ◽  
Wei Ding ◽  
Chang Liu
Keyword(s):  
Fusarium Oxysporum ◽  
Inhibitory Activity ◽  
Defense Response ◽  
Endophytic Bacteria ◽  
Rice Seedling ◽  
Seedling Blight ◽  
Bacillus Velezensis ◽  
Secondary Bile Acid ◽  
Pathogen Inhibition

Seedling blight, caused by the fungus Fusarium oxysporum, significantly lowers rice production globally. Earlier reports have opined that endophytic bacteria strains could be possible biocontrol agents, but the mechanistic actions involved are still unclear. Therefore, this study aimed to isolate the endophytic bacteria with high inhibitory activity and elucidate its possible mechanisms for inducing resistance by metabolomics. The results showed that mdj-36 had the strongest in vitro pathogen inhibition of F. oxysporum, while mdj-34 displayed the lowest inhibitory activity identified as Bacillus velezensis strains. Metabolomic analyses demonstrated that B. velezensis mdj-36 growth medium could produce higher organic acids, terpenes, and diterpene than B. velezensis mdj-34. Further investigation revealed that ‘secondary bile acid biosynthesis’ and ‘glycerophospholipid metabolism’ pathways played essential roles in defense response towards F. oxysporum. This study’s findings provide a credible theoretical basis for the possible use of the B. velezensis strain against rice seedling blight.

Genomics-Driven Discovery of a Symbiont-Specific Cyclopeptide from Bacteria Residing in the Rice Seedling Blight Fungus

ChemBioChem ◽  
2018 ◽  
Vol 19 (20) ◽  
pp. 2167-2172 ◽  
Author(s):  
Sarah P. Niehs ◽  
Benjamin Dose ◽  
Kirstin Scherlach ◽  
Martin Roth ◽  
Christian Hertweck
Keyword(s):  
Rice Seedling ◽  
Seedling Blight

scholarly journals Breaking down walls to live in harmony

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Natalia Requena ◽  
Reinhard Fischer
Keyword(s):  
Rice Seedling ◽  
Seedling Blight

Some of the proteins and enzymes that allow bacteria to enter living fungal cells and cause rice seedling blight have been identified.

scholarly journals Genome Sequence ofBurkholderia plantariiZJ171, a Tropolone-Producing Bacterial Pathogen Responsible for Rice Seedling Blight

2016 ◽  
Vol 4 (6) ◽  
Author(s):  
Yuan Qian ◽  
Haruna Matsumoto ◽  
Wenzhuo Li ◽  
Guonian Zhu ◽  
Yasuyuki Hashidoko ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Draft Genome ◽  
Bacterial Pathogen ◽  
Rice Seedling ◽  
Causal Agent ◽  
Draft Genome Sequence ◽  
Seedling Blight ◽  
Coding Sequences ◽  
Insight Into

Burkholderia plantariiis the causal agent of rice seedling blight. Here, we report the draft genome sequence ofB. plantarii, which contains 8,020,831 bp, with a G+C content of 68.66% and a predicted 7,688 coding sequences. The annotated genome sequence will provide further insight into its pathogenicity.

scholarly journals Carot-4-en-9,10-Diol, a Conidiation-Inducing Sesquiterpene Diol Produced by Trichoderma virens PS1-7 upon Exposure to Chemical Stress from Highly Active Iron Chelators

2013 ◽  
Vol 79 (6) ◽  
pp. 1906-1914 ◽  
Author(s):  
Mengcen Wang ◽  
Makoto Hashimoto ◽  
Yasuyuki Hashidoko
Keyword(s):  
Intracellular Signaling ◽  
Metabolic Response ◽  
Rice Seedling ◽  
Iron Chelators ◽  
Chemical Stress ◽  
Dependent Manner ◽  
Trichoderma Virens ◽  
Seedling Blight ◽  
Content Type ◽  
Highly Active

ABSTRACTTo screen biocontrol agents againstBurkholderia plantarii, the causative agent of rice seedling blight, we employed catechol, an analog of the virulence factor tropolone, to obtain chemical stress-resistant microorganisms. The fungal isolate PS1-7, identified as a strain ofTrichoderma virens, showed the highest resistance to catechol (20 mM) and exhibited efficacy as a biocontrol agent for rice seedling blight. During investigation of metabolic traits ofT. virensPS1-7 exposed to catechol, we found a secondary metabolite that was released extracellularly and uniquely accumulated in the culture. The compound induced by chemical stress due to catechol was subsequently isolated and identified as a sesquiterpene diol, carot-4-en-9,10-diol, based on spectroscopic analyses.T. virensPS1-7 produced carot-4-en-9,10-diol as a metabolic response to tropolone at concentrations from 0.05 to 0.2 mM, and the response was enhanced in a dose-dependent manner, similar to its response to catechol at concentrations from 0.1 to 1 mM. Some iron chelators, such as pyrogallol, gallic acid, salicylic acid, and citric acid, at 0.5 mM also showed activation ofT. virensPS1-7 production of carot-4-en-9,10-diol. This sesquiterpene diol, formed in response to chemical stress, promoted conidiation ofT. virensPS1-7, suggesting that it is involved in an autoregulatory signaling system. In a bioassay of the metabolic and morphological responses ofT. virensPS1-7, conidiation in hyphae grown on potato dextrose agar (PDA) plates was either promoted or induced by carot-4-en-9,10-diol. Carot-4-en-9,10-diol can thus be regarded as an autoregulatory signal inT. virens, and our findings demonstrate that intrinsic intracellular signaling regulates conidiation ofT. virens.

scholarly journals Spatial-Temporal Characteristic Analysis of Ethnic Toponyms Based on Spatial Information Entropy at the Rural Level in Northeast China

Entropy ◽  
2020 ◽  
Vol 22 (4) ◽  
pp. 393 ◽  
Author(s):  
Fei Zhao ◽  
Yao Fu ◽  
Guize Luan ◽  
Sujin Zhang ◽  
Jingzhi Cai ◽  
...  
Keyword(s):  
Ethnic Groups ◽  
Information Entropy ◽  
Northeast China ◽  
Spatial Information ◽  
Distribution Characteristics ◽  
Rural Settlements ◽  
Temporal Database ◽  
Characteristic Analysis ◽  
Data Set ◽  
Cultural Connotations

As a symbol language, toponyms have inherited the unique local historical culture in the long process of historical development. As the birthplace of Manchu, there are many toponyms originated from multi-ethnic groups (e.g., Manchu, Mongol, Korean, Hui, and Xibe) in Northeast China which possess unique cultural connotations. This study aimed to (1) establish a spatial-temporal database of toponyms in Northeast China using a multi-source data set, and identify their ethnic types and origin times; and (2) explore the geographical distribution characteristics of ethnic toponyms and the evolution of rural settlements by comparing the spatial analysis and spatial information entropy methods. The results found that toponyms reflect not only the spatial distribution characteristics of the density and direction of ethnic groups, but also the migration law of rural settlements. Results also confirm that toponyms contain unique cultural connotations and provide a theoretical basis for the protection and promotion of the cultural connotations of toponyms. This research provides an entropic perspective and method for exploring the spatial-temporal evolutionary characteristics of ethnic groups and toponym mapping.

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