scholarly journals First Report of a Soft Rot of Philodendron ‘Con-go’ in China Caused by Dickeya dieffenbachiae

Plant Disease ◽  
2012 ◽  
Vol 96 (3) ◽  
pp. 452-452 ◽  
Author(s):  
B. R. Lin ◽  
H. F. Shen ◽  
J. N. Zhou ◽  
X. M. Pu ◽  
Z. N. Chen ◽  
...  
Keyword(s):  
16S Rdna ◽  
Phylogenetic Trees ◽  
Soft Rot ◽  
Gyrb Gene ◽  
Control Treatment ◽  
Gene Sequences ◽  
16S Rdna Gene ◽  
First Report ◽  
Rdna Gene ◽  
Plastic Bags

Philodendron is a popular foliage plant cultivated in interiorscapes of homes, offices, and malls throughout China. A severe outbreak of a soft rot of Philodendron ‘Con-go’ occurred in Guangzhou, China from 2010 to 2011. The disease was characterized by leaf infections starting as pinpoint spots that are water soaked and yellow to pale brown. The lesions are sometimes surrounded by a diffuse yellow halo. When the humidity is high and temperatures are warm to hot, the spots expand rapidly, becoming slimy, irregular, and sunken with light tan centers, darker brown borders, and diffused yellow margins and may involve the entire leaf in a few days. An invasion of the midrib and larger veins by the causal bacterium often results in advancement into the petiole and stem. A survey of three areas of production of Philodendron ‘Con-go’ (5 ha) in Guangzhou revealed that 91% of the fields were affected at an incidence ranging from 15 to 30%. Of 41 bacterial isolates obtained from lesions, three were selected randomly for further characterization. All strains were gram negative, negative for oxidase and positive for catalase and tryptophanase (indole production), and utilized citrate, tartrate, malonate, glucose, sucrose, fructose, and maltose but not glucopyranoside, trehalose, or palatinose. Biolog analysis (version 4.20.05, Hayward, CA) identified the isolates as Pectobacterium chrysanthemi (SIM 0.804 to 0.914). According to Samson et al. (1), it was renamed as a Dickeya sp. PCR was performed on the 16S rDNA gene with primers 27f and 1495r (3) and 1,423 bp of the 16S rDNA gene (GenBank No. JN709491) showed 99% identity to P. chrysanthemi (GenBank No. AF373202), and 98% to Dickeya dieffenbachiae (GenBank No. JF311644). Additionally, the gyrB gene was amplified with primers gyrB-f1 (5′-atgtcgaattcttatgactcctc-3′) and gyrB-r1 (5′-tcaratatcratattcgcygctttc-3′) designed based on all the submitted gyrB gene sequences of Dickeya spp. The dnaX gene was amplified with primers dnaXf and dnaXr (2). The products were sequenced and phylogeny analyses were performed by means of MEGA 5.05. Results showed that the gyrB and the dnaX genes of the strains were 98% homologous to those of D. dieffenbachiae (GenBank Nos. JF311652 and GQ904757). Therefore, on the basis of phylogenetic trees of the 16S rDNA, gyrB, and dnaX gene sequences, the bacterial isolate named PC1 is related to D. dieffenbachiae (100% bootstrap values). Pathogenicity of each of the three strains on Philodendron ‘Con-go’ was confirmed by injecting 60 50-day-old seedlings each with 0.1 ml of the isolate suspension (108 CFU/ml) into the leaves. Another 60 were injected with sterile water to serve as the control treatment. Plants were enclosed in plastic bags and returned to the greenhouse under 50% shade at 32°C day and 28°C night temperatures with high humidity. After 72 h, all the injected plants started to show symptoms similar to those observed on field plants, but no symptoms appeared on the control plants. The reisolates were identical to the inoculated strains in biochemical characteristics. Bacteria characteristic of the inoculated strains were not reisolated from the control plants. To our knowledge, this is the first report of D. dieffenbachiae causing soft rot of Philodendron ‘Con-go' in China. References: (1) R. Samson et al. Evol. Microbiol. 55:1415, 2005. (2) M. Sławiak et al. Eur. J. Plant Pathol. 125:245, 2009. (3) W. G. Weisbury et al. J. Bacteriol. 173:697, 1991.

scholarly journals First Report of a Soft Rot of Phalaenopsis aphrodita Caused by Dickeya dieffenbachiae in China

Plant Disease ◽  
2012 ◽  
Vol 96 (5) ◽  
pp. 760-760 ◽  
Author(s):  
J. N. Zhou ◽  
B. R. Lin ◽  
H. F. Shen ◽  
X. M. Pu ◽  
Z. N. Chen ◽  
...  
Keyword(s):  
16S Rdna ◽  
Large Scale ◽  
Soft Rot ◽  
The Philippines ◽  
Gyrb Gene ◽  
Bacterial Suspension ◽  
Sterile Water ◽  
Gene Sequences ◽  
First Report ◽  
Tropical Asia

Phalaenopsis orchids, originally from tropical Asia, are mainly planted in Thailand, Singapore, Malaysia, the Philippines, and Taiwan and have gained popularity from consumers all over the world. The cultivation area of Phalaenopsis orchids has been rising and large-scale bases have been established in mainland China, especially South China because of suitable environmental conditions. In September 2011, a soft rot of Phalaenopsis aphrodita was found in a Phalaenopsis planting base in Guangzhou with an incidence of ~15%. Infected plants initially showed water-soaked, pale-to-dark brown pinpoint spots on leaves that were sometimes surrounded by a yellow halo. Spots expanded rapidly with rising humidity and temperatures, and in a few days, severely extended over the blade with a light tan color and darker brown border. Lesions decayed with odorous fumes and tissues collapsed with inclusions exuding. The bacterium advanced to the stem and pedicle. Finally, leaves became papery dry and the pedicles lodged. Six diseased samples were collected, and bacteria were isolated from the edge of symptomatic tissues after sterilization in 0.3% NaOCl for 10 min, rinsing in sterile water three times, and placing on nutrient agar for culture. Twelve representative isolates were selected for further characterization. All strains were gram negative, grew at 37°C, were positive for indole production, and utilized malonate, glucose, and sucrose but not glucopyranoside, trehalose, or palatinose. Biolog identification (version 4.20.05, Hayward, CA) was performed and Pectobacterium chrysanthemi (SIM 0.868) was confirmed for the tested isolates (transfer to genus Dickeya). PCR was used to amplify the 16S rDNAgene with primers 27f and 1492r, dnaX gene with primers dnaXf and dnaXr (3), and gyrB gene with primers gyrBf (5′-GAAGGYAAAVTKCATCGTCAGG-3′) and gyrB-r1 (5′-TCARATATCRATATTCGCYGCTTTC-3′) designed on the basis of the published gyrB gene sequences of genus Dickeya. BLASTn was performed online, and phylogeny trees (100% bootstrap values) were created by means of MEGA 5.05 for these gene sequences, respectively. Results commonly showed that the representative tested strain, PA1, was most homologous to Dickeya dieffenbachiae with 98% identity for 16S rDNA(JN940859), 97% for dnaX (JN989971), and 96% for gyrB (JN971031). Thus, we recommend calling this isolate D. dieffenbachiae PA1. Pathogenicity tests were conducted by injecting 10 P. aphrodita seedlings with 100 μl of the bacterial suspension (1 × 108 CFU/ml) and another 10 were injected with 100 μl of sterile water as controls. Plants were inoculated in a greenhouse at 28 to 32°C and 90% relative humidity. Soft rot symptoms were observed after 2 days on the inoculated plants, but not on the control ones. The bacterium was isolated from the lesions and demonstrated identity to the inoculated plant by the 16S rDNA sequence comparison. Previously, similar diseases of P. amabilis were reported in Tangshan, Jiangsu, Zhejiang, and Wuhan and causal agents were identified as Erwinia spp. (2), Pseudomonas grimontii (1), E. chrysanthemi, and E. carotovora subsp. carovora (4). To our knowledge, this is the first report of D. dieffenbachiae causing soft rot disease on P. aphrodita in China. References: (1) X. L. Chu and B. Yang. Acta Phytopathol. Sin. 40:90, 2010. (2) Y. M. Li et al. J. Beijing Agric. Coll. 19:41, 2004. (3) M. Sławiak et al. Eur. J. Plant Pathol. 125:245, 2009. (4) Z. Y. Wu et al. J. Zhejiang For. Coll. 27:635, 2010.

scholarly journals First Report of a γ 3-Proteobacterium Associated with Diseased Strawberries in Italy

Plant Disease ◽  
2007 ◽  
Vol 91 (12) ◽  
pp. 1688-1688 ◽  
Author(s):  
F. Terlizzi ◽  
A. R. Babini ◽  
C. Lanzoni ◽  
A. Pisi ◽  
R. Credi ◽  
...  
Keyword(s):  
16S Rdna ◽  
16S Rdna Gene ◽  
First Report ◽  
Genome Region ◽  
Rdna Gene ◽  
Rdna Sequences ◽  
Pcr Products ◽  
Emilia Romagna Region ◽  
Young Leaves ◽  
Stolbur Phytoplasma

During the fall seasons of 2005 and 2006, diseased strawberry plants (Fragaria × ananassa Duch.) were observed in nurseries and production fields in Ferrara, Forli-Cesena, and Ravenna provinces (Emilia-Romagna region, northern Italy). Symptoms consisted of a conspicuous plant stunting with a poor root system. Older leaves rolled upward and displayed a marked premature purplish discoloration, while young leaves were cupped, chlorotic, generally reduced in size, and had shortened petioles. This strawberry disorder was similar to “marginal chlorosis”, an infectious disease occurring in France that can be induced by two different phloem-limited uncultured bacteria: the γ 3-proteobacterium ‘Candidatus Phlomobacter fragariae’ and the stolbur phytoplasma (16SrXII-A). In strawberry production fields, ‘Ca. P. fragariae’ is reported as being the prevalent agent of this disease (1). Sixty-seven diseased plants were collected from production fields and nurseries for testing for ‘Ca. P. fragariae’. Leaf samples were analyzed by 4′,6-diamidine-2-phenylindole staining and PCR. Forty samples showed fluorescent DNA in the phloem, whereas no fluorescence was observed in symptomless strawberries. When tested by PCR with primers Fra4/Fra5, which amplify a 550-bp fragment of the 16S rDNA region of ‘Ca. P. fragariae’ (1), 13 of 36 strawberries from production fields and 1 of 31 nursery plants gave a positive reaction. On the other hand, 21 samples from nurseries and 5 from production fields tested positive for stolbur phytoplasma (3). No amplification was obtained with DNA from symptomless or healthy strawberry plants. Sequencing Fra4/Fra5 amplicons from three samples (GenBank Accession Nos. DQ362916–DQ362918) showed a 98.1 to 98.6% and a 98.3 to 98.8% identity with the published sequences of the French isolate “LG2001” (GenBank Accession No. AM110766) and the Japanese isolate J-B (GenBank Accession No. AB246669) of ‘Ca. P. fragariae’, respectively. Higher homology (99.2 to 99.8%) was found with another bacterium-like organism (BLO) of the γ 3-proteobacteria subgroup (GenBank Accession No. AY057392) associated with the syndrome “basses richesses” of sugar beet (SBR). Furthermore, PCR assays performed with primers Pfr1/Pfr4, specific for spoT gene of ‘Ca. P. fragariae’, did not show any amplification with DNA from the 14 diseased strawberry plants tested. This is in agreement with the SBR BLO identification (2). To better characterize the Italian isolates, the full-length 16S rDNA gene was analyzed with primers fd1/Fra4 and Fra5/rp1, which amplify the 5′ and 3′ region of 16S rDNA gene of the proteobacteria, respectively (2). PCR products from eight isolates were sequenced, and the 16S rDNA sequences obtained (GenBank Accession Nos. DQ538372–DQ538379) showed a 96.4 to 97.3% identity with the known ‘Ca. P. fragariae’ isolates, while a higher homology (99.4 to 99.9%) was again found with the SBR BLO. To our knowledge, this is the first report of a γ 3-proteobacterium affecting strawberry in Italy. In the genome region analyzed, our isolates are more similar to the SBR BLO than to ‘Ca. P. fragariae’. Further work is in progress to investigate incidence, geographical distribution, epidemiology, and host range of this pathogen in Italy. References: (1) J. L. Danet et al. Phytopathology 93:644, 2003. (2) O. Semetey et al. Phytopathology 97:72, 2007. (3) F. Terlizzi et al. Plant Dis. 90:831, 2006.

scholarly journals Antioxidant Potential of Pediococcus Pentosaceus Strains from the Sow Milk Bacterial Collection in Weaned Piglets

2021 ◽  
Author(s):  
Leli Wang ◽  
Qihang Liu ◽  
Yuwei Chen ◽  
Xinlei Zheng ◽  
Chuni Wang ◽  
...  
Keyword(s):  
16S Rdna ◽  
Signaling Pathway ◽  
Commensal Bacteria ◽  
Functional Evaluation ◽  
Gene Sequences ◽  
16S Rdna Gene ◽  
Maternal Milk ◽  
Pediococcus Pentosaceus ◽  
Rdna Gene ◽  
Rdna Sequencing

Abstract Background: In modern animal husbandry, breeders pay increasing attention to improving sow nutrition during pregnancy and lactation to favor the health of neonates. Sow milk is a main food for piglets during their first three weeks of life, which is not only a rich repository of essential nutrients and a broad range of bioactive compounds, but also an indispensable source of commensal bacteria. Maternal milk microorganisms are important sources of commensal bacteria for neonatal gut. Bacteria from maternal milk may serve as an additive to confer a health benefit on the composition of the indigenous microbiota of piglets. Methods: The sow milk microbiota was collected using the culturomics methods of Continuous Culture and Interval Sampling, following by the identification of 16S rDNA gene sequences. To screen potential probiotics, the functional evaluation was conducted to assess their antagonistic activity against pathogens in vitro and evaluate their resistance against oxidative stress in damaged Drosophila induced by paraquat. In piglet feeding trial, a total of 54 newborn suckling piglets were chosen from nine sows and randomly assigned to three treatments with different concentration of a candidate strain. Multiple approaches were carried out to verify its antioxidant function including western blotting, enzyme activity analysis, metabolomics and 16S rDNA sequencing. Results: The 1240 isolates were screened out from the sow milk microbiota and grouped into 271 bacterial taxa based on a nonredundant set of 16S rDNA gene sequences. Among 80 Pediococcus isolates, a new Pediococcus pentosaceus strain (SMM914) showed best performance in inhibition ability against swine pathogens and in Drosophila model challenged by paraquat. Pretreatment of piglets with SMM914 induces the Nrf2-Keap1 antioxidant signaling pathway and greatly affected the pathways of amino acid metabolism and lipid metabolism in plasma. In colon, Lactobacillus was significantly increased in the high dose of SMM914 group compared with the control group. Conclusion: SMM914 functions as a promising probiotic conferring antioxidant capacity by activating the Nrf2-Keap1 antioxidant signaling pathway in piglets. Our study provided useful resources for deeply understanding the relationships between the maternal microbiota and offspring.

BACTERIAS ENDOFÍTICAS DE ELODEA POTAMOGETON (“LLACHU”) DEL LAGO TITICACA

SCIENTIARVM ◽  
2015 ◽  
Vol 1 (1) ◽  
pp. 35-38
Author(s):  
Pedro Ubaldo Coila Añasco ◽  
◽  
Julio César Bernabé Ortiz ◽  
Domingo Alberto Ruelas ◽  
◽  
...  
Keyword(s):  
16S Rdna ◽  
Endophytic Bacteria ◽  
Phylogenetic Trees ◽  
Isoamyl Alcohol ◽  
The United States ◽  
Luria Bertani ◽  
16S Rdna Gene ◽  
Symbiotic Interaction ◽  
Rdna Gene ◽  
Raoultella Terrigena

ABTRACT: The “llachu” (Elodea potamogeton) is an aquatic plant from Lake Titicaca, food for the cattle of the circumlacustrine ring. Some areas of the lake have been eutrophied by pollution; even so, the plant grows. Being one of the survival mechanisms, the symbiotic interaction with microorganisms, the objective of the study was to isolate and molecularly characterize some endophytic bacteria of the plant. For isolation, the samples were washed and disinfected with 70% alcohol, 0.5% sodium hypochlorite and 80% Tween; then, it was homogenized and an aliquot seeded in Luria-Bertani (LB) medium, three strains were chosen to be reseeded on solid LB agar. From the pure strains, DNA was extracted with the phenol-chloroform-isoamyl alcohol mixture, quantifying by spectrophotometry. The 16S rDNA gene was amplified by PCR; amplicons were submitted to Functional Biosciences Inc. in the United States for sequencing. The sequences were edited with BioEdit 7.0.0 and similar sequences were chosen with BLASTn from GenBank, to perform multiple alignment of sequences with Clustal W. To determine evolutionary relationships, MEGA7 was used, constructing phylogenetic trees by the Neighbor-Joining method. Molecular analysis shows that the Sample10ped strain corresponds to Pantoea sp. with an identity greater than 76%; the Sample11pe strain to Pseudomonas sp. with 100% identity; and, to the strain Sample12ped to Raoultella terrígena sp. or Klebsiella sp. with an identity of 99%. The sequences of the last two were registered in GenBank, whose accessions are SUB4288247 and SUB4252655. Keywords: Endophytic bacteria, Elodea potamogeton, 16S rDNA gene, phylogeny

scholarly journals First Report of a Leaf Spot of Radermachera sinica in China Caused by Bacillus megaterium

Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1425-1425 ◽  
Author(s):  
Y. L. Li ◽  
Z. Zhou ◽  
Y. C. Yuan ◽  
J. R. Ye
Keyword(s):  
16S Rdna ◽  
Bacillus Megaterium ◽  
Leaf Spot ◽  
Disease Incidence ◽  
Bacterial Suspension ◽  
Distilled Water ◽  
Biochemical Tests ◽  
16S Rdna Gene ◽  
First Report ◽  
Rdna Gene

Radermachera sinica is widely planted as an ornamental plant in homes, offices, and malls in China. A leaf spot of R. sinica occurred in Luoyang, China, from 2013 to 2014. Lesions mostly occurred in wounds and were irregular with light brown centers and purple borders. One or more lesions on a leaf sometimes covered the entire blade. Eighty plants were surveyed in Luoyang, with disease incidence of 17%. Five millimeter pieces from the borders of lesions were surface-disinfected with 75% ethanol for 30 s, 1% sodium hypochlorite for 5 min, washed three times in sterilized distilled water, placed on nutrient agar (NA) medium at 25°C in darkness, and incubated for 24 to 48 h. Four white, round, smooth, and shiny colonies were selected for further identification. All strains were gram-positive, aerobic rods with many peritrichous flagella, and could grow in medium containing 5% NaCl. The strains were positive for catalase, starch hydrolysis, liquefaction of gelatin, reduction of nitrate, acid production from glucose, mannitol, maltose, lactose, xylose, and pectinose. The strains were positive for phenylalanine deaminase, decomposition of tyrosine, and utilization of citrate. The strains were identified by biochemical tests as Bacillus megaterium (1). To confirm pathogenicity, the strains were grown on NA for 48 h and suspended in sterile distilled water to produce a suspension with a final concentration of 108 CFU/ml. Healthy leaves of biennial R. sinica plants were sterilized with 75% ethanol and washed three times with sterilized distilled water. Fresh wounds were made with a sterile needle on the healthy leaves. Each of four strains was tested by spray inoculation with a bacterial suspension on three leaves. Sterile distilled water was used as negative control. Plants were enclosed in plastic bags and placed in a growth chamber at 28°C with 80% relative humidity. After 5 days, water-soaked lesions were observed. Two weeks later, lesions 4 mm in diameter turned light brown with purple borders, and most of lesions occurred in puncture wounds. Symptoms similar to those observed on field plants developed on all inoculated leaves, while no symptoms appeared on the control leaves. B. megaterium was re-isolated from the lesions of inoculated leaves, but not from the control leaves. To confirm the bacterial identification, PCR was performed on the 16S rDNA gene with P1/P2 (P1: CAGAGTTTGATCCTGGCT, P2: AGGAGGTGATCCAGCCGCA) (2) and 1,463 bp of the 16S rDNA gene (GenBank Accession No. KJ789369) showed 100% sequence identity to B. megaterium DSM 319 (NC_014103.1). To our knowledge, this is the first report of a leaf spot of R. sinica caused by B. megaterium in China as well as anywhere in the world. References: (1) P. Vos et al. Bergey's Manual of Systematic Bacteriology. Vol 3: The Firmicutes. Springer, 2009. (2) W. G. Weisbury et al. J. Bacteriol. 173:697, 1991.

scholarly journals Phylogenetic relationship of Salmonella enterica strains in Tehran, Iran, using 16S rRNA and gyrB gene sequences

2011 ◽  
Vol 5 (06) ◽  
pp. 465-472 ◽  
Author(s):  
Mercedeh Tajbakhsh ◽  
Babak Noory Nayer ◽  
Kamyar Motavaze ◽  
Pedram Kharaziha ◽  
Mohsen Chiani ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rdna ◽  
Phylogenetic Relationship ◽  
Salmonella Enterica ◽  
Phylogenetic Trees ◽  
Gyrb Gene ◽  
Rrna Gene ◽  
Gene Sequences ◽  
Comparison Results ◽  
Relationship Of

Introduction: We assessed whether 16S rDNA and gyrB gene sequences, alone or combined, were suitable for determining the phylogenetic relationship among Salmonella enterica strains isolated from Tehran, Iran.  Patients over five years of age enrolled in an acute diarrheal surveillance project in Tehran province between May 2004 and October 2006 were selected as our study group.  Methodology: 16S ribosomal DNA (rDNA) and gyrB genes from 40 Salmonella isolates obtained from patients with acute diarrhea were sequenced and the data was used to generate phylogenetic trees that facilitated isolate comparison. Results: Salmonella strains clustered into five to seven phylogenetic groups, dependent on analysis of 16S rDNA (1546 bp), gyrB (1256 bp) or a combination of the two genes.  By 16S rDNA sequence analysis, only strains of Salmonella enterica  serovar Typhi ( S. Typhi)  clustered exclusively together.  gyrB sequences permitted clustering of all the S. Typhi and S. Paratyphi A isolates, and clustering of S. Enteritidis into two separate but exclusive groups.  Concatenation of the two data sets did not significantly improve the resolution of the strains compared to the gyrB gene.  None of the analyses completely resolved S. enterica Paratyphi B and C into mutually exclusive groups.   Conclusion: Sequencing of gyrB represents a potentially useful tool for determining the phylogenetic relationship of S. enterica strains in Tehran, Iran. Genetic analysis of the 16S rRNA gene alone or in combination with gyrB did not increase the resolution between serotypes of S. enterica.  We speculate that inclusion of additional genetic markers would improve the sensitivity of the analysis.

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