scholarly journals Isolation and Identification of taxonomically diverse bacterial endophytes from citrus in Punjab Pakistan

2022 ◽  
Author(s):  
Sagheer Atta
Keyword(s):  
Burkholderia Cepacia ◽  
Biological Control Agent ◽  
Bacterial Species ◽  
Pcr Amplification ◽  
Control Agent ◽  
Total Production ◽  
Font Size ◽  
Isolation And Identification ◽  
Bacterial Populations ◽  
Gamma Proteobacteria

<pre style="margin: 0in 0in 0.0001pt; font-size: 10pt; font-family: "Courier New"; caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); text-align: justify; line-height: 26.666664123535156px;"> <span style="font-size: 12pt; line-height: 32px; font-family: "Times New Roman", serif;">Citrus is an economically important fruit crop grown in all provinces of Pakistan, while Punjab accounting for 95 percent of total production due to its favorable climate for citrus production. Commercially grown varieties in Pakistan include sweet oranges, grapefruits, Mandarine, Lime, and lemon. The goal of this research was to see how diverse the cultivable bacterial populations are found in citrus cultivars. Out of 90 isolated cultures, 37 endophytic bacterial species and 15 </span><span style="font-size: 12pt; line-height: 32px; font-family: "Times New Roman", serif;">different genera of bacteria were characterized</span><span style="font-size: 12pt; line-height: 32px; font-family: "Times New Roman", serif;"> based on morphological, biochemical, and molecular methods from citrus leaves. All the isolated bacteria were subjected to PCR amplification through 16S rDNA followed by sequencing. </span><span style="font-size: 12pt; line-height: 32px; font-family: "Times New Roman", serif;">RDP base classification revealed that class Bacilli has the largest percentage of isolates, whereas class Alpha, Beta, and Gamma Proteobacteria have the lowest percentage among all genotypes used. According to the findings, the phylum Firmicutes contains a common genus (Brevibacterium, 1%; Enterococcus, 6%; Staphylococcus, 7% and Bacillus, 60%). Alpha (Rhizobium) beta (Burkholderia cepacia; Comamonas terigena) gamma Proteobacteria (Enterobacter hermachei (1%), Klebsiella pneumoniae (1%), Proteus mirabilis (8%), Pseudomonas aeruginosa (5%), Psychrobacter pulmonis and Yersinia molalretti (1%) respectively. </span><span style="font-size: 12pt; line-height: 32px; font-family: "Times New Roman", serif;">These results revealed that cultivars of the plants might contribute to the structure and endophytic bacterial communities associated with citrus. Endophytes extracted from leaf samples of different citrus cultivars in Pakistan are reported for the first time. The idea of employing endophytes bacteria to produce enzymes stimulate plant growth, and its purpose as a biological control agent will be investigated in the future.</span><span style="font-size: 12pt; line-height: 32px; font-family: "Times New Roman", serif;"><o:p></o:p></span></pre>

scholarly journals Influence of Tomato Genotype on Growth of Inoculated and Indigenous Bacteria in the Spermosphere

2001 ◽  
Vol 67 (2) ◽  
pp. 514-520 ◽  
Author(s):  
Holly M. Simon ◽  
Kevin P. Smith ◽  
Jeremy A. Dodsworth ◽  
Bobbi Guenthner ◽  
Jo Handelsman ◽  
...  
Keyword(s):  
Genetic Basis ◽  
Biological Control Agent ◽  
Bacterial Species ◽  
Control Agent ◽  
Growth Patterns ◽  
Host Genotype ◽  
Host Effect ◽  
Tomato Genotype ◽  
Total Bacteria ◽  
Soil Changes

ABSTRACT We previously demonstrated a genetic basis in tomato for support of the growth of a biological control agent, Bacillus cereusUW85, in the spermosphere after seed inoculation (K. P. Smith, J. Handelsman, and R. M. Goodman, Proc. Natl. Acad. Sci. USA 96:4786–4790, 1999). Here we report results of studies examining the host effect on the support of growth of Bacillus andPseudomonas strains, both inoculated on seeds and recruited from soil, using selected inbred tomato lines from the recombinant inbred line (RIL) population used in our previous study. Two tomato lines, one previously found to support high and the other low growth ofB. cereus UW85 in the spermosphere, had similar effects on growth of each of a diverse, worldwide collection of 24 B. cereus strains that were inoculated on seeds and planted in sterilized vermiculite. In contrast, among RILs that differed for support of B. cereus UW85 growth in the spermosphere, we found no difference for support of growth of the biocontrol strainsPseudomonas fluorescens 2-79 or Pseudomonas aureofaciens AB254. Thus, while the host effect on growth extended to all strains of B. cereus examined, it was not exerted on other bacterial species tested. When seeds were inoculated with a marked mutant of B. cereus UW85 and planted in soil, RIL-dependent high and low support of bacterial growth was observed that was similar to results from experiments conducted in sterilized vermiculite. When uninoculated seeds from two of these RILs were planted in soil, changes in population levels of indigenousBacillus and fluorescent Pseudomonas bacteria differed, as measured over time by culturing and direct microscopy, from growth patterns observed in the inoculation experiments. Neither RIL supported detectable levels of growth of indigenousBacillus soil bacteria, while the line that supported growth of inoculated B. cereus UW85 supported higher growth of indigenous fluorescent pseudomonads and total bacteria. The vermiculite system used in these experiments was predictive for growth of B. cereus UW85 inoculated on seeds and grown in soil, but the patterns of growth of inoculated strains—bothBacillus and Pseudomonas spp.—did not reflect host genotype effects on indigenous microflora recruited from soil to the spermosphere.

Dominant symbiotic bacteria associated with wild medfly populations reveal a bacteriocin-like killing phenotype: a ‘cold-case’ study

2019 ◽  
Vol 110 (4) ◽  
pp. 457-462
Author(s):  
Silvia Ciolfi ◽  
Laura Marri
Keyword(s):  
Bacterial Species ◽  
Klebsiella Oxytoca ◽  
Pcr Amplification ◽  
Fruit Trees ◽  
Antagonistic Activity ◽  
Culture Collection ◽  
Symbiotic Bacteria ◽  
Bacterial Populations

AbstractThe gut of the agricultural pest Ceratitis capitata hosts a varied community of bacteria, mainly Enterobacteriaceae, that were implicated in several processes that increase the fitness of the insect. In this study, we investigated the antagonistic activity in vitro of Klebsiella oxytoca strains isolated in the 1990s from the alimentary tract of wild medflies collected from different varieties of fruit trees at diverse localities. Assays were carried out against reference strains (representative of Gram-negative and -positive bacterial species) of the American Type Culture Collection (ATCC). Eight Klebsiella, out of 11, expressed a killing activity against Escherichia coli ATCC 23739, and Enterobacter cloacae ATCC 13047; among the eight strains, at least one showed activity against Salmonella typhimurium ATCC 23853. Genomic DNA derived from all Klebsiella strains was then subjected to PCR amplification using specific primer pairs designed from each of the four bacteriocin (KlebB, C, D, CCL) sequences found so far in Klebsiella. KlebD primer pairs were the only to produce a single product for all strains expressing the killing phenotype in vitro. One of the amplicons was cloned and sequenced; the DNA sequence shows 93% identity with a plasmid-carried colicin-D gene of a strain of Klebsiella michiganensis, and 86% identity with the sequence encoding for the klebicin D activity protein in K. oxytoca. Our work provides the first evidence that dominant symbiotic bacteria associated with wild medfly populations express a killing phenotype that may mediate inter and intraspecies competition among bacterial populations in the insect gut in vivo.

scholarly journals Pathogenicity of Burkholderia cepacia (Pseudomonas cepacia) in four onion genotypes (Allium sp.)

1969 ◽  
Vol 80 (3) ◽  
pp. 123-134
Author(s):  
Rodrigo O. Campo ◽  
Mildred Zapata
Keyword(s):  
Puerto Rico ◽  
Burkholderia Cepacia ◽  
Biological Control Agent ◽  
Control Agent ◽  
Phytopathogenic Fungi ◽  
Pseudomonas Cepacia ◽  
Randomized Design ◽  
Sour Skin ◽  
Different Levels ◽  
Yellow Onion

Onion is one of the major crops in Puerto Rico.The bacterium Burkholderia cepacia (basonym: Pseudomonas cepacia) is the causal agent of the onion disease sour skin. In Puerto Rico the strain B. cepacia UPR-5C has been reported as a biological control agent of various phytopathogenic fungi. At present, the pathogenic characteristics of this strain are unknown. The pathogenicity of B. cepacia UPR-5C was determined in four commercial onion genotypes, yellow, red scailions, white Spanish and slip, by using a complete randomized design with split plots. The onion genotypes were inoculated with bacteria of 10e CFU/ml from each growth phase and with the filtrates corresponding to each phase. Symptoms were evaluated seven days after inoculation.Treatments with cells, but not filtrates, induced symptoms in the yellow onion genotype. The red, white and slip genotypes were not susceptible, but the bacterium is pathogenic to yellow onions. There are, however, different levels of resistance within the species.

Interaction of a biological control agent, Chaetomium globosum, with seed coat microflora

1982 ◽  
Vol 28 (4) ◽  
pp. 431-437 ◽  
Author(s):  
J. P. Hubbard ◽  
G. E. Harman ◽  
C. J. Eckenrode
Keyword(s):  
Seed Coat ◽  
Plant Pathogens ◽  
Biological Control Agent ◽  
Control Agent ◽  
Selective Medium ◽  
Chaetomium Globosum ◽  
Bacterial Populations ◽  
Soilborne Plant Pathogens ◽  
Pea Seeds ◽  
Logarithmic Growth

The mechanism by which Chaetomium globosum, applied as ascospores to squash, snap bean, and pea seeds, reduces damage caused by larvae of the seed-corn maggot, Hylemya platura (Meigen), and soilborne plant pathogens was investigated. Chaetomium globosum ascospores germinate rapidly and cover the seed coat with a dense mat of mycelium soon after seeds are planted in soil. However, if seeds are not treated with C. globosum before planting, other organisms rapidly colonize the seed coat during germination. Seed flies oviposit near seeds in response to the growth of pseudomonads on the seed surface. Studies employing a selective medium indicate that Pseudomonas become the most prevalent genus occurring on the seed coat during seed germination. Treatment of seed with C. globosum suppresses the logarithmic growth of pseudomonads on the seed coat but affects neither bacterial populations in the soil surrounding the seed nor germination of Fusarium solani f. sp. pisi chlamydospores, either on the seed coat or in the soil surrounding the seed. A water-insoluble antibiotic was extracted from C. globosum treated seeds. After systemtic examination of other possibilities, it was concluded that this nondiffusable antibiotic substance produced by C. globosum suppresses pseudomonads responsible for stimulation of oviposition by seed flies as well as the soilborne plant pathogens.

Culturable bacterial populations associated with ectomycorrhizae of Norway spruce stands with different degrees of decline in the Czech Republic

2010 ◽  
Vol 56 (1) ◽  
pp. 52-64 ◽  
Author(s):  
Lorena Avidano ◽  
Maurizio Rinaldi ◽  
Roberto Gindro ◽  
Pavel Cudlín ◽  
Maria Giovanna Martinotti ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Burkholderia Cepacia ◽  
Forest Decline ◽  
Bacterial Species ◽  
Principal Component ◽  
Atmospheric Pollutants ◽  
Culturable Bacteria ◽  
Bacterial Populations ◽  
Spruce Stands ◽  
Associated Species

The aim of this study was to determine which species of culturable bacteria are associated with ectomycorrhizae (ECM) of Norway spruce (Picea abies (L.) Karst) in the Sudety Mountains, exposed for years to atmospheric pollutants, acid rain, and climatic stress, and to identify particular species that have adapted to those conditions. Biolog identification was performed on bacterial species from ECM of adult spruce trees and seedlings of stands with low, intermediate, and high forest decline. Bacterial diversity in ECM associated with adult spruce trees, seedlings, and seedlings grown on monoliths was calculated; although the expected values appeared to vary widely, no significant differences among sites were observed. Dendrograms based on the identified bacterial species showed that stands with low forest decline clustered separately from the others. Principal component analysis of the normalized data for ECM-associated species showed a clear separation between stands with high forest decline and stands with low forest decline for seedlings and a less evident separation for adult spruce trees. In conclusion, shifts in ECM-associated culturable bacterial populations seem to be associated with forest decline in Norway spruce stands. Some bacterial species were preferentially associated with mycorrhizal roots depending on the degree of forest decline; this was more evident in seedlings where the species Burkholderia cepacia and Pseudomonas fluorescens were associated with, respectively, ECM of the most damaged stands and those with low forest decline.

scholarly journals The isolation and identification of pathogenic fungi from Tessaratoma papillosa Drury (Hemiptera: Tessaratomidae)

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3888 ◽  
Author(s):  
Xiang Meng ◽  
Junjie Hu ◽  
Gecheng Ouyang
Keyword(s):  
Entomopathogenic Fungi ◽  
Southern China ◽  
Biological Control Agent ◽  
Pathogenic Fungi ◽  
Control Agent ◽  
Morphological Identification ◽  
Pest Species ◽  
Stink Bug ◽  
Isolation And Identification ◽  
Highly Virulent

Background Litchi stink-bug, Tessaratoma papillosa Drury (Hemiptera: Tessaratomidae), is one of the most widespread and destructive pest species on Litchi chinensis Sonn and Dimocarpus longan Lour in Southern China. Inappropriate use of chemical pesticides has resulted in serious environmental problems and food pollution. Generating an improved Integrated Pest Management (IPM) strategy for litchi stink-bug in orchard farming requires development of an effective biological control agent. Entomopathogenic fungi are regarded as a vital ecological factor in the suppression of pest populations under field conditions. With few effective fungi and pathogenic strains available to control litchi stink-bug, exploration of natural resources for promising entomopathogenic fungi is warranted. Methods & Results In this study, two pathogenic fungi were isolated from cadavers of adult T. papillosa. They were identified as Paecilomyces lilacinus and Beauveria bassiana by morphological identification and rDNA-ITS homogeneous analysis. Infection of T. papillosa with B. bassiana and P. lilacinus occurred initially from the antennae, metameres, and inter-segmental membranes. Biological tests showed that the two entomopathogenic fungi induced high mortality in 2nd and 5th instar nymphs of T. papillosa. B. bassiana was highly virulent on 2nd instar nymphs of T. papillosa, with values for cadaver rate, LC50 and LT50 of 88.89%, 1.92 × 107 conidia/mL and 4.34 days respectively. Discussion This study provides two valuable entomopathogenic fungi from T. papillosa. This finding suggests that the highly virulent P. lilacinus and B. bassiana play an important role in the biocontrol of T. papillosa in China. These pathogenic fungi had no pollution or residue risk, and could provide an alternative option for IPM of litchi stink-bug.

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