Comparative transcriptomics reveals a highly polymorphic Xanthomonas HrpG virulence regulon

Monnens Thomas Quiroz, Roux Brice, Cunnac Sébastien, Charbit Erika, Carrère Sébastien, Lauber Emmanuelle, Jardinaud Marie-Françoise, Darrasse Armelle, Arlat Mathieu, Szurek Boris, Pruvost Olivier, Jacques Marie Agnès, Gagnevin Lionel, Koebnik Ralf, Noel Laurent D., Boulanger Alice. 2024. Comparative transcriptomics reveals a highly polymorphic Xanthomonas HrpG virulence regulon. BMC Genomics, 25:777, 17 p.

https://doi.org/10.1186/s12864-024-10684-6

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Url - jeu de données - Entrepôt autre : https://doi.org/10.57745/9OTYNJ

Résumé : Background: Bacteria of the genus Xanthomonas cause economically significant diseases in various crops. Their virulence is dependent on the translocation of type III effectors (T3Es) into plant cells by the type III secretion system (T3SS), a process regulated by the master response regulator HrpG. Although HrpG has been studied for over two decades, its regulon across diverse Xanthomonas species, particularly beyond type III secretion, remains understudied. Results: In this study, we conducted transcriptome sequencing to explore the HrpG regulons of 17 Xanthomonas strains, encompassing six species and nine pathovars, each exhibiting distinct host and tissue specificities. We employed constitutive expression of plasmid-borne hrpG*, which encodes a constitutively active form of HrpG, to induce the regulon. Our findings reveal substantial inter- and intra-specific diversity in the HrpG* regulons across the strains. Besides 21 genes directly involved in the biosynthesis of the T3SS, the core HrpG* regulon is limited to only five additional genes encoding the transcriptional activator HrpX, the two T3E proteins XopR and XopL, a major facility superfamily (MFS) transporter, and the phosphatase PhoC. Interestingly, genes involved in chemotaxis and genes encoding enzymes with carbohydrate-active and proteolytic activities are variably regulated by HrpG*. Conclusions: The diversity in the HrpG* regulon suggests that HrpG-dependent virulence in Xanthomonas might be achieved through several distinct strain-specific strategies, potentially reflecting adaptation to diverse ecological niches. These findings enhance our understanding of the complex role of HrpG in regulating various virulence and adaptive pathways, extending beyond T3Es and the T3SS.

Mots-clés Agrovoc : Xanthomonas, génome, phylogénie, activité enzymatique, virulence, expression des gènes, génie génétique, séquence nucléotidique

Mots-clés libres : XANTHOMONAS, HrpG, Type III secretion system, Regulon diversity, Transcriptome sequencing

Classification Agris : H20 - Maladies des plantes

Champ stratégique Cirad : CTS 4 (2019-) - Santé des plantes, des animaux et des écosystèmes

Agences de financement hors UE : Agence Nationale de la Recherche, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement

Projets sur financement : (FRA) Etude comparative des génomes et des transcriptomes de Xanthomonas phytopathogènes, (FRA) L'étoffe d'un pathogène : comment Xanthomonas s'adapte à la vie in planta, (FRA) Towards a Unified theory of biotic Interactions: the roLe of environmental, (FRA) The Toulouse-Perpignan

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