scholarly journals Lysogeny in Rhizobium Leguminosarum and Rh. Trifolii

1963 ◽  
Vol 16 (3) ◽  
pp. 597 ◽  
Author(s):  
E A Schwinghamer ◽  
DJ Reinrardt
Keyword(s):  
Host Range ◽  
Host Specificity ◽  
Ultraviolet Light ◽  
Rhizobium Leguminosarum ◽  
Clear Plaque ◽  
Rhizobial Species ◽  
Lysogenic Conversion ◽  
Light Inducibility

Seven lysogenic strains-three of Rh. legumino8urum and four of Rh. trifoliiwere identified among a total of 54 strains from these two species and Rh. phaseoli. The Rh.leguminosarum strains may be multiply lysogenic; two of them also produce lethal agents resembling bacteriocins in their effect. Lysogeny was confumed by standard criteria of ultraviolet light inducibility, self.immunity, and reductive ability. Lysogenic conversion involving symbiotic characteristics was not observed. A minimum of six different temperate phages and two clear-plaque-forming variant phages were identified. The host range includes strains of the above three rhizobial species, but not of Rh. melilotii. Variation in host specificity of some phages following host passage is under investigation.

scholarly journals A Draft Genome Sequence of Pseudomonas syringae pv. tomato T1 Reveals a Type III Effector Repertoire Significantly Divergent from That of Pseudomonas syringae pv. tomato DC3000

2009 ◽  
Vol 22 (1) ◽  
pp. 52-62 ◽  
Author(s):  
Nalvo F. Almeida ◽  
Shuangchun Yan ◽  
Magdalen Lindeberg ◽  
David J. Studholme ◽  
David J. Schneider ◽  
...  
Keyword(s):  
Host Range ◽  
Host Specificity ◽  
Pseudomonas Syringae ◽  
Genome Sequence ◽  
Draft Genome ◽  
Draft Genome Sequence ◽  
Tomato Dc3000 ◽  
Type Iii ◽  
Host Range Determination ◽  
Range Determination

Diverse gene products including phytotoxins, pathogen-associated molecular patterns, and type III secreted effectors influence interactions between Pseudomonas syringae strains and plants, with additional yet uncharacterized factors likely contributing as well. Of particular interest are those interactions governing pathogen-host specificity. Comparative genomics of closely related pathogens with different host specificity represents an excellent approach for identification of genes contributing to host-range determination. A draft genome sequence of Pseudomonas syringae pv. tomato T1, which is pathogenic on tomato but nonpathogenic on Arabidopsis thaliana, was obtained for this purpose and compared with the genome of the closely related A. thaliana and tomato model pathogen P. syringae pv. tomato DC3000. Although the overall genetic content of each of the two genomes appears to be highly similar, the repertoire of effectors was found to diverge significantly. Several P. syringae pv. tomato T1 effectors absent from strain DC3000 were confirmed to be translocated into plants, with the well-studied effector AvrRpt2 representing a likely candidate for host-range determination. However, the presence of avrRpt2 was not found sufficient to explain A. thaliana resistance to P. syringae pv. tomato T1, suggesting that other effectors and possibly type III secretion system–independent factors also play a role in this interaction.

Ecological release in lizard endoparasites from the Atlantic Forest, northeast of the Neotropical Region

Parasitology ◽  
2020 ◽  
Vol 147 (4) ◽  
pp. 491-500
Author(s):  
Adonias A. Martins Teixeira ◽  
Pablo Riul ◽  
Samuel Vieira Brito ◽  
João A. Araujo-Filho ◽  
Diêgo Alves Teles ◽  
...  
Keyword(s):  
Host Range ◽  
Host Specificity ◽  
Atlantic Forest ◽  
Positive Relationship ◽  
Niche Breadth ◽  
Neotropical Region ◽  
Parasite Abundance ◽  
Ecological Release ◽  
Parasite Richness

AbstractWe compared lizard endoparasite assemblages between the Atlantic Forest and naturally isolated forest enclaves to test the ecological release hypothesis, which predicts that host specificity should be lower (large niche breadth) and parasite abundance should be greater for parasites from isolated forest enclaves (poor assemblages) than for parasites from the coastal Atlantic Forest (rich assemblages). Parasite richness per specimen showed no difference between the isolated and non-isolated areas. Parasite abundance did not differ between the isolated and non-isolated areas but showed a positive relationship with parasite richness considering all areas (isolated and non-isolated). Furthermore, host specificity was positively related to parasite richness. Considering that host specificity is inversely proportional to the host range infected by a parasite, our results indicate that in assemblages with greater parasite richness, parasites tend to infect a smaller range of hosts than do those in simple assemblages. In summary, our study partially supports the ecological release hypothesis: in assemblages with greater parasite richness, lizard parasites from Atlantic Forest are able to increase their parasite abundance (per host), possibly through facilitated infection; however, the amplitude of infected hosts only expands in poor assemblages (lower parasite richness).

Host Range Alteration of the Bioherbicidal FungusAlternaria crassawith Fruit Pectin and Bant Filtrates

Weed Science ◽  
1994 ◽  
Vol 42 (3) ◽  
pp. 487-491 ◽  
Author(s):  
C. Douglas Boyette ◽  
Hamed K. Abbas
Keyword(s):  
Host Range ◽  
Host Specificity ◽  
Water Soluble ◽  
Weed Species ◽  
Eastern Black Nightshade ◽  
Black Nightshade ◽  
Hemp Sesbania ◽  
Greenhouse Tests

In greenhouse tests, the host specificity ofAlternaria crassa(Sacc.) Rands, a mycoherbicide for jimsonweed was altered by the addition of water-soluble filtrates of jimsonweed and hemp sesbania or fruit pectin to fungal conidia suspensions. Several crop and weed species that were resistant to the fungus alone exhibited various degrees of susceptibility following these amendments, with 100% mortality occurring to the weeds hemp sesbania, showy crotalaria, and eastern black nightshade when treated with the fungus/pectin mixture. Nonhost plants that were inoculated with conidial mixtures amended with sucrose or cellulose were not affected. Modification of host specificity of this pathogen could have an influence on its bioherbiddal potential

scholarly journals Restriction of Host Range by the sym2 Allele of Afghan Pea Is Nonspecific for the Type of Modification at the Reducing Terminus of Nodulation Signals

1998 ◽  
Vol 11 (5) ◽  
pp. 418-422 ◽  
Author(s):  
Alexandra O. Ovtsyna ◽  
Rene Geurts ◽  
Ton Bisseling ◽  
Ben J. J. Lugtenberg ◽  
Igor A. Tikhonovich ◽  
...  
Keyword(s):  
Host Range ◽  
Bradyrhizobium Japonicum ◽  
Rhizobium Leguminosarum ◽  
Reducing Sugar ◽  
Introgression Lines ◽  
Fixed Nitrogen ◽  
Normal Frequency

Rhizobium leguminosarum bv. viciae strains producing lipo-chitin oligosaccharides (LCOs) that are O-acetylated at the reducing terminus are required for nodulation of wild pea cultivars originating from Afghanistan that possess the recessive sym2A allele. The O-acetylation of the reducing sugar of LCOs is mediated by the bacterial nodX gene, which presumably encodes an acetyltransferase. We found that for nodulation on Afghan pea cultivars and sym2A introgression lines the nodX gene can be functionally replaced by the nodZ gene of Bradyrhizobium japonicum, which encodes a fucosyltransferase that fucosylates the reducing terminus of LCOs. The structure of the nodules, which were induced with normal frequency, was typical for effective pea nodules, and they fixed nitrogen with the same efficiency as nodules induced by nodX-carrying strains.

Multiple host-specificity loci of the broad host-range Rhizobium sp. NGR234 selected using the widely compatible legume Vigna unguiculata

1987 ◽  
Vol 8 (6) ◽  
pp. 447-459 ◽  
Author(s):  
A. Lewin ◽  
C. Rosenberg ◽  
z. A. H. Meyer ◽  
C. H. Wong ◽  
L. Nelson ◽  
...  
Keyword(s):  
Host Range ◽  
Host Specificity ◽  
Vigna Unguiculata ◽  
Broad Host Range ◽  
Rhizobium Sp

scholarly journals Brazilian Peppertree Thrips Pseudophilothrips ichini (Hood) (Insecta: Thysanoptera: Phlaeothripidae)

EDIS ◽  
2020 ◽  
Vol 2020 (2) ◽  
Author(s):  
Patricia Prade ◽  
Carey R Minteer ◽  
James P Cuda
Keyword(s):  
Biological Control ◽  
Host Range ◽  
Host Specificity ◽  
Biological Control Agent ◽  
Control Agent ◽  
Severe Reduction ◽  
Limited Host Range

The Brazilian peppertree thrips, Pseudophilothrips ichini (Hood) (Thysanoptera: Phlaeothripidae), is an insect native to Brazil (Figure 1). This species has been studied for the last 20+ years as a potential biological control agent of Brazilian peppertree, Schinus terebinthifolia Raddi (Sapindales: Anacardiaceae), in Florida (Cuda et al. 2008; Cuda et al. 2008; Manrique at al. 2014; Wheeler et al. 2016a, b). Host specificity experiments demonstrated that Pseudophilothrips ichini has a limited host range (Cuda et al. 2008; Cuda et al. 2009; Wheeler et al. 2017) and can cause a severe reduction of Brazilian peppertree biomass (Manrique at al. 2014).https://edis.ifas.ufl.edu/in1270

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