Single gene enables plant pathogenic Pectobacterium to overcome host‐specific chemical defence

Abstract

Plants of the Brassicales order, including Arabidopsis and many common vegetables, produce toxic isothiocyanates to defend themselves against pathogens. Despite this defence, plant pathogenic microorganisms like Pectobacterium cause large yield losses in fields and during storage of crops. The bacterial gene saxA was previously found to encode isothiocyanate hydrolase that degrades isothiocyanates in vitro. Here we demonstrate in planta that saxA is a virulence factor that can overcome the chemical defence system of Brassicales plants. Analysis of the distribution of saxA genes in Pectobacterium suggests that saxA from three different phylogenetic origins are present within this genus. Deletion of saxA genes representing two of the most common classes from P. odoriferum and P. versatile resulted in significantly reduced virulence on Arabidopsis thaliana and Brassica oleracea. Furthermore, expressing saxA from a plasmid in a potato‐specific P. parmentieri strain that does not naturally harbour this gene significantly increased the ability of the strain to macerate Arabidopsis. These findings suggest that a single gene may have a significant role in defining the host range of a plant pathogen.

Research Progress on Phytopathogenic Fungi and Their Role as Biocontrol Agents

“…A large number of studies have shown that the combined use of pathogenic fungi and other biological control methods (including bacteria, plant-derived insecticides, attractants, and natural enemies) can significantly improve the effectiveness of insect-pathogenic fungi (Figure 4) (Zhao et al, 2014;Van den Bosch et al, 2019). Fungus-based insecticides have great potential as a form of pest control.…”

Ontogenetic differences in the chemical defence of flea beetles influence their predation risk

“…One replicate was excluded from the analysis because the H. axyridis larva had moulted to the fourth larval instar. Survival data were analysed using a parametric survival regression model with a log-logistic hazard distribution in R (Therneau, 2015). Logrank tests with Benjamini and Hochberg correction were performed using the r package survminer (Kassambara & Kosinski, 2018).…”

Functional Variation in Dipteran Gut Bacterial Communities in Relation to Their Diet, Life Cycle Stage and Habitat

“…GBCs can be confronted with these compounds, depending on the gut structure of the insect and their spatial distribution in the gut (foregut, midgut, or hindgut). Several studies showed that members of GBCs possess detoxification mechanisms, which may be beneficial to the GBCs as well as their hosts [15,38].…”

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