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Ristaino, J. B.

Publications and source records attributed to Ristaino, J. B..

2 recordsLinked to original sources
bioRxiv2020

Global historic pandemics caused by the FAM-1 genotype of the Irish potato pathogen Phytophthora infestans

The FAM-1 genotype of Phytophthora infestans caused late blight in the 1840s in the US and Europe and was responsible for the Irish famine. We examined 140 herbarium specimens collected between 1845 and 1991 from six continents and used 12-plex microsatellite genotyping (SSR) to identify FAM-1 and the mtDNA lineage (Herb-1/ Ia) present in historic samples. FAM-1 was detected in approximately 73% of the historic specimens and was found on 6 continents. The US-1 genotype was found in only 27% of the samples and was found later on all continents except Australia/Oceania. FAM-1 was the first genotype detected in almost all the former British colonies from which samples were available. The data from historic samples suggest the FAM-1 genotype was widespread, diverse, and spread more widely than US-1. The famine lineage spread to six continents over 140 years, and likely spread during global colonization from Europe.

evolutionary biology↗
bioRxiv2020

Protective Plant Immune Responses are Elicited by Bacterial Outer Membrane Vesicles

Bacterial outer membrane vesicles (OMVs) perform a variety of functions in bacterial survival and virulence. In mammalian systems, OMVs activate immune responses and have been exploited as vaccines. However, little work has focused on the role that OMVs play during interactions with plant hosts. Here we report that OMVs from the pathogenic Pseudomonas syringae and the beneficial Pseudomonas fluorescens activate plant immune responses that protect against bacterial and oomycete pathogens. OMVs from these two species display different sensitivity to biochemical stressors, which could indicate differences in OMV cargo packaging. Furthermore, our study shows that OMV-induced protective immune responses are T3SS- and protein-independent, while OMV-mediated seedling growth inhibition largely depends on protein cargo. Importantly, OMV-mediated plant responses are distinct from those triggered by PAMP/MAMPs or effector molecules alone. OMVs provide a unique opportunity to study virulence factors in combination and add a new layer of interaction and complexity to host-microbe interactions.

microbiology↗