Xylose Isomerase Depletion Enhances Virulence of Xanthomonas citri subsp. citri in Citrus aurantifolia

• Published in: International journal of molecular sciences Vol. 24; no. 14; p. 11491
• Main Authors: Alexandrino, André Vessoni, Prieto, Evandro Luis, Nicolela, Nicole Castro Silva, da Silva Marin, Tamiris Garcia, Dos Santos, Talita Alves, de Oliveira da Silva, João Pedro Maia, da Cunha, Anderson Ferreira, Behlau, Franklin, Novo-Mansur, Maria Teresa Marques
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 15-07-2023; MDPI
• Subjects: Bacteria; Biodiesel fuels; Biofuels; citrus canker; Disease; Enzymes; Food quality; Fruits; Genes; Genomes; Genomics; Glucose; hrp genes; Metabolism; pathogenicity; Proteins; Virulence; xylA; xylose isomerase; xylR; pathogenicity; xylose isomerase; citrus canker; xylA; hrp genes; xylR
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms241411491

Citrus canker, caused by the bacterium
(Xcc), is one of the most devastating diseases for the citrus industry. Xylose is a constituent of the cell wall of plants, and the ability of Xcc to use this carbohydrate may play a role in virulence. Xcc has two genes codifying for xylose isomerase (XI), a bifunctional enzyme that interconverts D-xylose into D-xylulose and D-glucose into D-fructose. The aim of this work was to investigate the functional role of the two putative XI ORFs, XAC1776 (
) and XAC4225 (
), in Xcc pathogenicity. XI-coding genes of Xcc were deleted, and the single mutants (XccΔxylA1 or XccΔxylA2) or the double mutant (XccΔxylA1ΔxylA2) remained viable. The deletion of one or both XI genes (
and/or
) increased the aggressiveness of the mutants, causing disease symptoms. RT-qPCR analysis of wild strain and
deletion mutants grown in vivo and in vitro revealed that the highest expression level of
and
was observed in vivo for the double mutant. The results indicate that XI depletion increases the expression of the
regulatory genes in Xcc. We concluded that the intracellular accumulation of xylose enhances Xcc virulence.