scholarly journals Bacillus velezensis CE 100 Inhibits Root Rot Diseases (Phytophthora spp.) and Promotes Growth of Japanese Cypress (Chamaecyparis obtusa Endlicher) Seedlings

2021 ◽  
Vol 9 (4) ◽  
pp. 821
Author(s):  
Jae-Hyun Moon ◽  
Sang-Jae Won ◽  
Chaw Ei Htwe Maung ◽  
Jae-Hyeok Choi ◽  
Su-In Choi ◽  
...  
Keyword(s):  
Root Rot ◽  
Plant Growth Promoting Rhizobacteria ◽  
Chamaecyparis Obtusa ◽  
Fertilizer Treatment ◽  
Bacillus Velezensis ◽  
Japanese Cypress ◽  
Phytophthora Root Rot ◽  
Abnormal Growth ◽  
Phytophthora Spp ◽  
Plant Growth Promoting

Root rot diseases, caused by phytopathogenic oomycetes, Phytophthora spp. cause devastating losses involving forest seedlings, such as Japanese cypress (Chamaecyparis obtusa Endlicher) in Korea. Plant growth-promoting rhizobacteria (PGPR) are a promising strategy to control root rot diseases and promote growth in seedlings. In this study, the potential of Bacillus velezensis CE 100 in controlling Phytophthora root rot diseases and promoting the growth of C. obtusa seedlings was investigated. B. velezensis CE 100 produced β-1,3-glucanase and protease enzymes, which degrade the β-glucan and protein components of phytopathogenic oomycetes cell-wall, causing mycelial growth inhibition of P. boehmeriae, P. cinnamomi, P. drechsleri and P. erythoroseptica by 54.6%, 62.6%, 74.3%, and 73.7%, respectively. The inhibited phytopathogens showed abnormal growth characterized by swelling and deformation of hyphae. B. velezensis CE 100 increased the survival rate of C. obtusa seedlings 2.0-fold and 1.7-fold compared to control, and fertilizer treatment, respectively. Moreover, B. velezensis CE 100 produced indole-3-acetic acid (IAA) up to 183.7 mg/L, resulting in a significant increase in the growth of C. obtusa seedlings compared to control, or chemical fertilizer treatment, respectively. Therefore, this study demonstrates that B. velezensis CE 100 could simultaneously control Phytophthora root rot diseases and enhance growth of C. obtusa seedlings.

scholarly journals Plant growth-promoting rhizobacteria induced resistance in Jatropha curcas through phenyl propanoid metabolism against Rhizoctoniabataticola

2017 ◽  
Vol 9 (1) ◽  
pp. 121-128
Author(s):  
S. Kumar ◽  
M. Singh ◽  
Sushil Sharma
Keyword(s):  
Plant Growth ◽  
Pseudomonas Fluorescens ◽  
Jatropha Curcas ◽  
Root Rot ◽  
Plant Growth Promoting Rhizobacteria ◽  
Systemic Resistance ◽  
Total Phenols ◽  
Phenyl Propanoid ◽  
Plant Growth Promoting ◽  
Growth Promoting

The root rot disease in Jatropha curcas L. caused by Rhizoctonia. bataticola (Taub.) Butler has been recorded in causing 10-12 per cent mortality of 20-30 days old seedlings of Jatropha curcasin southern Haryana. The incidence of this disease has also been observed from other parts of Haryana too. Induction of systemic resistance in host plants through microbes and their bioactive metabolites are attaining popularity in modern agricultural practices. Studies on the plant growth-promoting rhizobacteria induced resistance in Jatropha curcas through phenyl propanoid metabolism against Rhizoctoniabataticola were undertaken at Chaudhary Charan Singh, Haryana Agricultural University, Regional Research Station, Bawal. Three plant growth-promoting rhizobacteria (PGPRs) viz., Pseudomonas maltophila, Pseudomonas fluorescens and Bacillus subtilis were evaluated for their potential to induce systemic resistance in Jatropha against root rot. The maximum increase of 97 per cent in total phenols, 120 per cent in peroxidase, 123 per cent in polyphenol oxidase, 101 per cent in phenylalanine ammonia lyase and 298 per cent in tyrosine ammonia lyase was detected in plants raised with Pseudomonas fluorescens+ Rhizoctoniaba-taticola inoculation in Jatropha curcas at 10 days post inoculation against control except total phenols where it was maximum (99%) at 30 DPI. There was slight or sharp decline in these parameters with age irrespective of inoculations. The pathogen challenged plants showed lower levels of total phenols and enzymes. The observations revealed that seed bacterization with Pseudomonas fluorescens results in accumulation of phenolics and battery of enzymes in response to pathogen infection and thereby induce resistance systemically.

scholarly journals Evaluating the Efficacy of the Systems Approach at Mitigating Five Common Pests in Oregon Nurseries

2014 ◽  
Vol 32 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Nancy K. Osterbauer ◽  
Melissa Lujan ◽  
Gary McAninch ◽  
S. Lane ◽  
Aaron Trippe
Keyword(s):  
Root Rot ◽  
Systems Approach ◽  
Phytophthora Root Rot ◽  
Potted Plants ◽  
Foliar Blight ◽  
Total Percentage ◽  
Phytophthora Spp ◽  
Root Weevils ◽  
Pest Incidence ◽  
Point Inspection

In Oregon, the U.S. Nursery Certification (USNCP), Grower Assisted Inspection (GAIP), and Shipping Point Inspection (SPI) programs are used to certify nursery plants as pest free. To compare the programs' effectiveness for mitigating pest risk, potted plants grown within two USNCP, two GAIP, and two SPI nurseries were surveyed for Phytophthora root rot (Phytophthora spp.), Phytophthora foliar blight (Phytophthora spp.), bittercress (Cardamine spp.), snails and slugs (Class Gastropoda), and root weevils (Otiorhynchus spp.). A total of 1,635 plots were surveyed in the nurseries, with one or more pests detected in 1,003 plots. Based on the total percentage of plots found infested with a pest, significantly fewer were detected in the GAIP nurseries (55%) than in the USNCP nurseries (68%). However, bittercress incidence was significantly higher in GAIP nurseries (21%), while snails and slugs incidence was significantly higher in USNCP nurseries (49%), and Phytophthora root rot incidence was significantly higher in SPI nurseries (31%). Also, the plant families grown by the nurseries had a significant impact on pest incidence for two of the target pests, Phytophthora root rot and root weevils. While the GAIP seemed the best at mitigating pest incidence overall, none of the certification programs was consistently the most effective against all five target pests.

scholarly journals Incidence of Phytophthora Root Rot of Fraser Fir in North Carolina and Sensitivity of Isolates of Phytophthora cinnamomi to Metalaxyl

Plant Disease ◽  
2000 ◽  
Vol 84 (6) ◽  
pp. 661-664 ◽  
Author(s):  
D. M. Benson ◽  
L. F. Grand
Keyword(s):  
North Carolina ◽  
Root Rot ◽  
Phytophthora Cinnamomi ◽  
Disease Incidence ◽  
The State ◽  
Systematic Sampling ◽  
Phytophthora Root Rot ◽  
Fraser Fir ◽  
Phytophthora Spp ◽  
Old Trees

A survey of Fraser fir Christmas trees in North Carolina for incidence of Phytophthora root rot was conducted during 1997 and 1998. Field sites (7- to 13-year-old trees) and nursery transplant beds (4- to 5-year-old trees) selected at random were surveyed based on foliar symptoms of Phytophthora root rot. Field sites were surveyed with a random transect method (>3,000 trees/field) or by counting all trees (<3,000 trees/field). Overall, incidence of Phytophthora root rot averaged 9% over the 58 field sites sampled, with a range of 0 to 75%. No relationship was found between number of years Fraser fir had been planted in the field site and disease incidence. Disease incidence did not increase as field sites were rotated through second or third crops of Fraser fir. Phytophthora spp. were recovered from 1.8% of asymptomatic trees sampled from 58 field sites across the state. P. cinnamomi accounted for 91% of the Phytophthora isolates recovered. In nursery transplant beds where a systematic sampling procedure was used, incidence of diseased trees averaged 2%, with a range of 0 to 12% across 16 locations. Recovery of Phytophthora spp. averaged 1.2% from root samples collected from 50 asymptomatic seedlings at each location. Isolates collected from the field and nursery transplant beds were grown on cornmeal agar incorporated with 0, 1, 1.25, 10, or 100 μg a.i. metalaxyl/ml. All 166 isolates of P. cinnamomi tested were sensitive to metalaxyl at 1 or 1.25 μg a.i. metalaxyl/ml. Although incidence of Phytophthora root rot has not increased in the state compared to a survey done in 1976 to 1977, the disease continues to limit production of Fraser fir in North Carolina.

scholarly journals Phytophthora Root Rot Modifies the Composition of the Avocado Rhizosphere Microbiome and Increases the Abundance of Opportunistic Fungal Pathogens

2021 ◽  
Vol 11 ◽  
Author(s):  
Itzel A. Solís-García ◽  
Oscar Ceballos-Luna ◽  
Elvis Marian Cortazar-Murillo ◽  
Damaris Desgarennes ◽  
Edith Garay-Serrano ◽  
...  
Keyword(s):  
Root Rot ◽  
Fungal Pathogens ◽  
Microbial Consortia ◽  
Plant Growth Promoting Bacteria ◽  
Its Sequencing ◽  
Phytophthora Root Rot ◽  
Rhizosphere Microbiome ◽  
Plant Growth Promoting ◽  
And Function ◽  
Induced Changes

The structure and function of rhizosphere microbial communities are affected by the plant health status. In this study, we investigated the effect of root rot on the avocado rhizosphere microbiome, using 16S rDNA and ITS sequencing. Furthermore, we isolated potential fungal pathogens associated with root rot symptoms and assessed their pathogenic activity on avocado. We found that root rot did not affect species richness, diversity or community structure, but induced changes in the relative abundance of several microbial taxa. Root rot increased the proportion of Pseudomonadales and Burkholderiales in the rhizosphere but reduced that of Actinobacteria, Bacillus spp. and Rhizobiales. An increase in putative opportunistic fungal pathogens was also detected in the roots of symptomatic trees; the potential pathogenicity of Mortierella sp., Fusarium spp., Lasiodiplodia sp. and Scytalidium sp., is reported for the first time for the State of Veracruz, Mexico. Root rot also potentially modified the predicted functions carried out by rhizobacteria, reducing the proportion of categories linked with the lipid and amino-acid metabolisms whilst promoting those associated with quorum sensing, virulence, and antibiotic resistance. Altogether, our results could help identifying microbial taxa associated to the disease causal agents and direct the selection of plant growth-promoting bacteria for the development of biocontrol microbial consortia.

scholarly journals Use of plant growth-promoting rhizobacteria (PGPR) and soil organic amendments for the management of root diseases complex of uridbean

2013 ◽  
Vol 54 (1) ◽  
pp. 65-70 ◽  
Author(s):  
I. A. Siddiqui ◽  
S. S.. Shaukat ◽  
S. Ehteshamul-Haque
Keyword(s):  
Root Rot ◽  
Organic Amendment ◽  
Organic Amendments ◽  
Plant Growth Promoting Rhizobacteria ◽  
Macrophomina Phaseolina ◽  
Root Knot Nematode ◽  
Neem Cake ◽  
Root Diseases ◽  
Plant Growth Promoting ◽  
Growth Promoting

Efficacy of two strains of <i>Pseudomonas aeruginosa</i> (Pa-5 and IE-2) and <i>Bacillus subtilis</i> isolate alone or in conjunction with neem cake or <i>Datura fastuosa</i> was tested for the management of three soilbrne root-infecting fungi including <i>Macrophomina phaseolina, Fusarium solani</i> and <i>Rhizoctonia solani</i> and the root-knot nematode, <i>Meloidogyne javanica</i> on uridbean. Biocontrol bacteria used in combination with either neem cake or <i>D.fastuosa</i> gave better control of the root-rot and root-knot infection with the enhancement of growth of uridbean compared to the use ofeither component alone. Neem cake l% w/w mixed with <i>P.aeruginosa</i> strain IE-2 caused greatest inhibition of the root-knot development due to <i>M.javanica, P.aeruginosa</i> and <i>B.subtilis</i> used with organic amendment also increased <i>Bradyrhizobium</i>-nodules in the root system.

The plant beneficial rhizobacterium Bacillus velezensis FZB42 controls the soybean pathogen Phytophthora sojae due to bacilysin production

2021 ◽  
Author(s):  
Xingshan Han ◽  
Dongxia Shen ◽  
Qin Xiong ◽  
Beihua Bao ◽  
Wenbo Zhang ◽  
...  
Keyword(s):  
Pectate Lyase ◽  
Plant Growth Promoting Rhizobacteria ◽  
Underlying Mechanism ◽  
Antibacterial Activities ◽  
Phytophthora Sojae ◽  
Plant Diseases ◽  
Economic Losses ◽  
Bacillus Velezensis ◽  
Soybean Seedlings ◽  
Plant Growth Promoting

Soybean root rot caused by the oomycete Phytophthora sojae is a serious soil-borne disease threatening soybean production in China. Bacillus velezensis FZB42 is a model strain for Gram-positive plant growth-promoting rhizobacteria and is able to produce multiple antibiotics. In this study, we demonstrated that B. velezensis FZB42 can efficiently antagonize P. sojae. The underlying mechanism for the inhibition was then investigated. The FZB42 mutants deficient in the synthesis of lipopeptides (bacillomycin D and fengycin), known for antifungal activities, and polyketides (bacillaene, difficidin, and macrolactin), known for antibacterial activities, were not impaired in their antagonism toward P. sojae ; in contrast, mutants deficient in bacilysin biosynthesis completely lost their antagonistic activities toward P. sojae , indicating that bacilysin was responsible for the activity. Isolated pure bacilysin confirmed this inference. Bacilysin was previously shown to be antagonistic mainly toward prokaryotic bacteria rather than eukaryotes. Here, we found that bacilysin could severely damage the hyphal structures of P. sojae and lead to the loss of their intracellular contents. A device was invented allowing interactions between P. sojae and B. velezensis FZB42 on nutrient agar. In this manner, the effect of FZB42 on P. sojae was studied by transcriptomics. FZB42 significantly inhibited the expression of P. sojae genes related to growth, macromolecule biosynthesis, pathogenicity, and ribosomes. Among them, the genes for pectate lyase were the most significantly downregulated. Additionally, we showed that bacilysin effectively prevents soybean sprouts from being infected by P. sojae and could antagonize diverse Phytophthora species, such as P. palmivora , P. melonis , P. capsici , P. litchi , and, most importantly, P. infestans . Importance Phytophthora spp. are widespread eukaryotic phytopathogens and often extremely harmful. Phytophthora can infect many types of plants important to agriculture and forestry and thus cause large economic losses. Perhaps due to inappropriate recognition of Phytophthora as a common pathogen in history, research on the biological control of Phytophthora is limited. This study shows that B. velezensis FZB42 can antagonize various Phytophthora species and prevent the infection of soybean seedlings by P. sojae . The antibiotic produced by FZB42, bacilysin, which was previously known to have antibacterial effectiveness, is responsible for the inhibitory action against Phytophthora . We further showed that some Phytophthora genes and pathways may be targeted in future biocontrol studies. Therefore, our data provide a basis for the development of new tools for the prevention and control of root and stem rot in soybean and other plant diseases caused by Phytophthora .

scholarly journals Development and Application of qPCR and RPA Genus- and Species-Specific Detection of Phytophthora sojae and P. sansomeana Root Rot Pathogens of Soybean

Plant Disease ◽  
2017 ◽  
Vol 101 (7) ◽  
pp. 1171-1181 ◽  
Author(s):  
J. Alejandro Rojas ◽  
Timothy D. Miles ◽  
Michael D. Coffey ◽  
Frank N. Martin ◽  
Martin I. Chilvers
Keyword(s):  
Mitochondrial Genome ◽  
Internal Control ◽  
Root Rot ◽  
Phytophthora Sojae ◽  
Diagnostic Tools ◽  
Specific Detection ◽  
Phytophthora Root Rot ◽  
Phytophthora Spp ◽  
Field Season ◽  
Species Specific

Phytophthora root rot of soybean, caused by Phytophthora sojae, is one of the most important diseases in the Midwestern United States, and is estimated to cause losses of up to 1.2 million metric tons per year. Disease may also be caused by P. sansomeana; however, the prevalence and damage caused by this species is not well known, partly due to limitations of current diagnostic tools. Efficient, accurate, and sensitive detection of pathogens is crucial for management. Thus, multiplex qPCR and isothermal RPA (recombinase polymerase amplification) assays were developed using a hierarchical approach to detect these Phytophthora spp. The assays consist of a genus-specific probe and two species-specific probes that target the atp9-nad9 region of the mitochondrial genome that is highly specific for the genus Phytophthora. The qPCR approach multiplexes the three probes and a plant internal control. The RPA assays run each probe independently with a plant internal control multiplexed in one amplification, obtaining a result in as little as 20 mins. The multicopy mitochondrial genome provides sensitivity with sufficient variability to discern among different Phytophthora spp. The assays were highly specific when tested against a panel of 100 Phytophthora taxa and range of Pythium spp. The consistent detection level of the assay was 100 fg for the qPCR assay and 10 pg for the RPA assay. The assays were validated on symptomatic plants collected from Michigan (U.S.) and Ontario (Canada) during the 2013 field season, showing correlation with isolation. In 2014, the assays were validated with samples from nine soybean producing states in the U.S. The assays are valuable diagnostic tools for detection of Phytophthora spp. affecting soybean.

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