Open AccessXanthomonas transcriptome inside cauliflower hydathodes reveals bacterial virulence strategies and physiological adaptations at early infection stages
Author(s) -
Luneau Julien S.,
Cerutti Aude,
Roux Brice,
Carrère Sébastien,
Jardinaud MarieFrançoise,
Gaillac Antoine,
Gris Carine,
Lauber Emmanuelle,
Berthomé Richard,
Arlat Matthieu,
Boulanger Alice,
Noël Laurent D.
Publication year - 2022
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1111/mpp.13117
Subject(s) - biology , xanthomonas campestris , xanthomonas , virulence , transcriptome , gene , microbiology and biotechnology , pathogen , type three secretion system , xanthomonas campestris pv. campestris , botany , genetics , gene expression
Xanthomonas campestris pv. campestris (Xcc) is a seed‐transmitted vascular pathogen causing black rot disease on cultivated and wild Brassicaceae. Xcc enters the plant tissues preferentially via hydathodes, which are organs localized at leaf margins. To decipher both physiological and virulence strategies deployed by Xcc during early stages of infection, the transcriptomic profile of Xcc was analysed 3 days after entry into cauliflower hydathodes. Despite the absence of visible plant tissue alterations and despite a biotrophic lifestyle, 18% of Xcc genes were differentially expressed, including a striking repression of chemotaxis and motility functions. The Xcc full repertoire of virulence factors had not yet been activated but the expression of the HrpG regulon composed of 95 genes, including genes coding for the type III secretion machinery important for suppression of plant immunity, was induced. The expression of genes involved in metabolic adaptations such as catabolism of plant compounds, transport functions, sulphur and phosphate metabolism was upregulated while limited stress responses were observed 3 days postinfection. We confirmed experimentally that high‐affinity phosphate transport is needed for bacterial fitness inside hydathodes. This analysis provides information about the nutritional and stress status of bacteria during the early biotrophic infection stages and helps to decipher the adaptive strategy of Xcc to the hydathode environment.