Ecological and evolutionary dynamics of a model facultative pathogen: Agrobacterium and crown gall disease of plants

Abstract

Summary Many important pathogens maintain significant populations in highly disparate disease and non‐disease environments. The consequences of this environmental heterogeneity in shaping the ecological and evolutionary dynamics of these facultative pathogens are incompletely understood. Agrobacterium tumefaciens, the causative agent for crown gall disease of plants has proven a productive model for many aspects of interactions between pathogens and their hosts and with other microbes. In this review, we highlight how this past work provides valuable context for the use of this system to examine how heterogeneity and transitions between disease and non‐disease environments influence the ecology and evolution of facultative pathogens. We focus on several features common among facultative pathogens, such as the physiological remodelling required to colonize hosts from environmental reservoirs and the consequences of competition with host and non‐host associated microbiota. In addition, we discuss how the life history of facultative pathogens likely often results in ecological tradeoffs associated with performance in disease and non‐disease environments. These pathogens may therefore have different competitive dynamics in disease and non‐disease environments and are subject to shifting selective pressures that can result in pathoadaptation or the within‐host spread of avirulent phenotypes.

The biotroph Agrobacterium tumefaciens thrives in tumors by exploiting a wide spectrum of plant host metabolites

“…A. tumefaciens is a niche‐constructing pathogen that genetically modifies the plant host genome by transferring a part (the transfer DNA (T‐DNA)) of its virulence Ti plasmid (Barton et al ., ; Dessaux & Faure, ). When expressed into the plant cell nucleus, the T‐DNA genes divert the host hormonal and metabolic pathways to provoke the development of galls or plant tumors (Deeken et al ., ).…”

A Small Regulatory RNA Controls Cell Wall Biosynthesis and Antibiotic Resistance

“…However, by means of differential RNA sequencing, sRNAs have been identified in essentially all bacterial and archaeal species studied thus far ( 13 , 14 ), including alphaproteobacteria, such as photosynthetic Rhodobacter species ( 15 ), plant-symbiotic rhizobia ( 16 – 18 ), and the mammalian pathogen Brucella abortus ( 19 ). The alphaproteobacterium Agrobacterium tumefaciens , also known as Agrobacterium fabrum ( 20 ), is a plant pathogen that has the unique ability to transfer part of its own DNA (T-DNA) into numerous eudicots ( 21 ). Integration of the T-DNA into the plant genome and subsequent expression of the involved genes leads to enhanced production of phytohormones and thereby to the formation of so-called crown gall tumors ( 22 , 23 ).…”

Isolation, Identification and Characterization of Endophytic Bacterium Rhizobium oryzihabitans sp. nov., from Rice Root with Biotechnological Potential in Agriculture

“…A 50% sequence identity was considered as the cut-off value for the orthologous clustering to obtain the pan and core genome. The virulence factors analysis of strain M15 T and R. radiobacter LMG140 T , a well known pathogenic species to cause the crown gall disease across thousands of different plant species [38], were performed using Virulence Factors of Pathogenic Bacteria. The secondary metabolite biosynthetic gene clusters of the 12 Rhizobium species were predicted using antiSMASH 5.0 [39].…”