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Laboratory of Plant-Microbe Interactions - LIPM

Laboratory of Plant-Microbe Interactions

Infectious strategies of Xanthomonas

Logo SIX

The SIX team wants to unravel the molecular mechanisms allowing the adaptation of phytopathogenic bacteria to their hosts with the long-term objective to propose knowledge-informed strategies to contend plant diseases.

Our work is focused on the plant pathogenic bacterium Xanthomonas campestris pv. campestris (Xcc) which is the causal agent of black rot of Brassicaceae. This bacterium infects plant of agronomical interest such as cabbage, broccoli or cauliflower as well as the model plant Arabidopsis thaliana.

Xcc belongs to a large genus which comprises 27 species that collectively affect more than 400 host plant species. The genome sequences of hundreds of Xanthomonas strains affecting economically important crops, such as rice, citrus, banana, tomato, pepper and bean are now publicly available making this genus a good model for comparative genomics.

We focus our studies on three major processes controlling the interaction with plants:

  • Type III Effectors (T3Es) which are bacterial proteins injected into plant cells by the Type III secretion System (T3SS). T3Es manipulate the physiology of host-plants either to suppress immunity or to manipulate plant physiology.
  • Physiological and regulatory processes allowing the adaptation of Xcc to the plant environments.

To carry out our studies we combine several approaches ranging from molecular biology, genetics, biochemistry, transcriptomics and genomics.

Overview fig

(A) Symptoms on cabbage leaf 16 days after hydathode infection with Xcc. (B) Lower side leaf print on rich medium  showing microbial community of a cabbage leaf 10 days after dipping with Xcc. Xcc colonies are present at the leaf margin. (C) Visualization of Xcc-GFP (green) on cabbage leaf surface by confocal microscopy.

Contacts: Laurent NOËL