scholarly journals The life history of the plant pathogen Pseudomonas syringae is linked to the water cycle

2008 ◽  
Vol 2 (3) ◽  
pp. 321-334 ◽  
Author(s):  
Cindy E Morris ◽  
David C Sands ◽  
Boris A Vinatzer ◽  
Catherine Glaux ◽  
Caroline Guilbaud ◽  
...  
Keyword(s):  
Life History ◽  
Pseudomonas Syringae ◽  
Plant Pathogen ◽  
Water Cycle ◽  
History Of

scholarly journals Inferring the Evolutionary History of the Plant Pathogen Pseudomonas syringae from Its Biogeography in Headwaters of Rivers in North America, Europe, and New Zealand

mBio ◽  
2010 ◽  
Vol 1 (3) ◽  
Author(s):  
C. E. Morris ◽  
D. C. Sands ◽  
J. L. Vanneste ◽  
J. Montarry ◽  
B. Oakley ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Plant Pathogen ◽  
Water Cycle ◽  
Phenotypic Diversity ◽  
Ice Nucleation ◽  
Content Type ◽  
History Of ◽  
Nucleation Activity ◽  
Ice Nucleation Activity ◽  
Agricultural Regions

ABSTRACTNonhost environmental reservoirs of pathogens play key roles in their evolutionary ecology and in particular in the evolution of pathogenicity. In light of recent reports of the plant pathogenPseudomonas syringaein pristine waters outside agricultural regions and its dissemination via the water cycle, we have examined the genetic and phenotypic diversity, population structure, and biogeography ofP. syringaefrom headwaters of rivers on three continents and their phylogenetic relationship to strains from crops. A collection of 236 strains from 11 sites in the United States, in France, and in New Zealand was characterized for genetic diversity based on housekeeping gene sequences and for phenotypic diversity based on measures of pathogenicity and ice nucleation activity. Phylogenetic analyses revealed several new genetic clades from water. The genetic structure ofP. syringaepopulations was not influenced by geographic location or water chemistry, whereas the phenotypic structure was affected by these parameters. Comparison with strains from crops revealed that the metapopulation ofP. syringaeis structured into three genetic ecotypes: a crop-specific type, a water-specific type, and an abundant ecotype found in both habitats. Aggressiveness of strains was significantly and positively correlated with ice nucleation activity. Furthermore, the ubiquitous genotypes were the most aggressive, on average. The abundance and diversity in water relative to crops suggest that adaptation to the freshwater habitat has played a nonnegligible role in the evolutionary history ofP. syringae. We discuss how adaptation to the water cycle is linked to the epidemiological success of this plant pathogen.IMPORTANCEMany pathogens have life cycles that involve survival and multiplication in nonhost environmental habitats. For human pathogens, numerous studies have revealed how adaptation to environmental habitats is linked to the evolution of their pathogenicity and emergence of pathogens. For plant pathogens, the link between adaptation to nonhost habitats and pathogenicity has not been explored. Here we have examined the genetic and phenotypic diversity of the plant pathogenPseudomonas syringaein headwaters of rivers on three continents and compared it to that of strains from crops. This model pathogen was chosen because it is widely abundant in habitats associated with the water cycle and in particular in pristine waters outside agricultural regions. This work reveals that there is considerable exchange of populations between freshwater and agricultural habitats and that those in the former contribute considerably to the diversification ofP. syringae.

Experimental life history of Echinostoma cinetorchis

1990 ◽  
Vol 28 (1) ◽  
pp. 39 ◽  
Author(s):  
S H Lee ◽  
J Y Chai ◽  
S T Hong ◽  
W M Sohn
Keyword(s):  
Life History ◽  
History Of

Queering Gender Identity Work: A Life History of a Black Transgender Woman

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Esethu Monakali
Keyword(s):  
Life History ◽  
Gender Identity ◽  
Public Spaces ◽  
Identity Work ◽  
Social Identities ◽  
Gender And Sexuality ◽  
Ongoing Effort ◽  
History Of ◽  
The Individual

This article offers an analysis of the identity work of a black transgender woman through life history research. Identity work pertains to the ongoing effort of authoring oneself and positions the individual as the agent; not a passive recipient of identity scripts. The findings draw from three life history interviews. Using thematic analysis, the following themes emerge: institutionalisation of gender norms; gender and sexuality unintelligibility; transitioning and passing; and lastly, gender expression and public spaces. The discussion follows from a poststructuralist conception of identity, which frames identity as fluid and as being continually established. The study contends that identity work is a complex and fragmented process, which is shaped by other social identities. To that end, the study also acknowledges the role of collective agency in shaping gender identity.

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