As strains of P. ananatis have been found to be pathogenic on a broad range of plant hosts as well as humans, the pan-genome was analyzed to identify potential molecular determinants underlying its pathogenicity.
The two lineages of the latter pathovar are pathogenic on different hosts (Anturium and Dieffenbachia) and hence may be considered as separate pathovars [ 30].
For example, strains that are pathogenic on the same host species can have divergent effector complements (Almeida et al. 2009; Baltrus et al. 2011; O'Brien et al. 2011), suggesting that P. syringae lineages are able to adapt to a given environment using multiple variations of effector repertoires (Lindeberg et al. 2012).
By contrast, Phytophthora kernoviae is pathogenic on a number of forest, heathland and ornamental angiosperm hosts in the United Kingdom (Brasier et al. [2005]; Beales et al. [2009]).
While both of these fungal species are pathogenic on the plant genera Theobroma and Herrania, M. roreri is not known to have any other hosts, whereas M. perniciosa has distinct biotypes that infect different host species [ 11].
Thus a parasite species that is pathogenic in one host species either do not infect the alternative host, or are less pathogenic and prolific.
Indeed, if on the one hand, microbial symbionts can confer a fitness gain on their arthropod hosts, including better nutrition [9], heat tolerance [10], [11], and resistance to pathogens [12], [13], [14], on the other hand, arthropod microbiota can be pathogenic for the host vector [15], [16], or can have deleterious effects on host reproduction [17], [18].
Whereas heightened immune responses are pathogenic, RA is paradoxically associated with impaired host defense to microbes.
None of the strains were pathogenic or able to cause mortality in hosts at 36°C.
