Transcriptional profiling of Xanthomonas campestris pv. campestris in viable but nonculturable state

Abstract

Background Xanthomonas campestris pv. campestris (Xcc) is an important seed-borne plant pathogenic bacteria that can cause a serious threat to cruciferous crops. Bacteria can enter into the viable but non-culturable (VBNC) state under stress conditions, and cause potential risks to agricultural production because the VBNC bacterial cells will evade culture-based detection. However, little is known about the mechanism of VBNC. Our previous study showed that Xcc could be induced into VBNC state by copper ion (Cu2+). Results Here, RNA-seq was performed to explore the mechanism of VBNC state. The results indicated that expression profiling was changed dramatically in the different VBNC stages (0 d, 1 d, 2 d and 10 d). Moreover, metabolism related pathways were enriched according to COG, GO and KEGG analysis of differentially expressed genes (DEGs). The DEGs associated with cell motility were down-regulated, whereas pathogenicity related genes were up-regulated. This study revealed that the high expression of genes related to stress response could trigger the active cells to VBNC state, while the genes involved in transcription and translation category, as well as transport and metabolism category, were ascribed to maintaining the VBNC state. Conclusion This study summarized not only the related pathways that might trigger and maintain VBNC state, but also the expression profiling of genes in different survival state of bacteria under stress. It provided a new kind of gene expression profile and new ideas for studying VBNC state mechanism in X. campestris pv. campestris.

The Viable but Non-Culturable (VBNC) State, a Poorly Explored Aspect of Beneficial Bacteria

“…In recent metabolomics studies of the VBNC state, it has been observed in various bacterial species that active metabolic pathways are linked to the transport and metabolism of inorganic ions, carbohydrates, and amino acids, as well as pathways involved in the synthesis of the cell wall, membrane, and envelope [ 128 ]. Additionally, it has been determined that during the VBNC state, there is an augmentation in the amino acid content, consequently leading to the alteration of specific amino acid metabolic pathways, such as the biosynthesis of aminoacyl-tRNA and the metabolism of arginine, proline, alanine, aspartate, and glutamate.…”