Global transcriptome and targeted metabolite analyses of roots reveal different defence mechanisms against Ralstonia solanacearum infection in two resistant potato cultivars

Abstract

Ralstonia solanacearum (Rs), the causal agent of bacterial wilt disease in an unusually wide range of host plants, including potato (Solanum tuberosum), is one of the most destructive phytopathogens that seriously reduces crop yields worldwide. Identification of defence mechanisms underlying bacterial wilt resistance is a prerequisite for biotechnological approaches to resistance breeding. Resistance to Rs has been reported only in a few potato landraces and cultivars. Our in vitro inoculation bioassays confirmed that the cultivars ‘Calalo Gaspar’ (CG) and ‘Cruza 148’ (CR) are resistant to Rs infection. Comparative transcriptome analyses of CG and CR roots, as well as of the roots of an Rs-susceptible cultivar, ‘Désirée’ (DES), were carried out two days after Rs infection, in parallel with their respective noninfected controls. In CR and DES, the upregulation of chitin interactions and cell wall-related genes was detected. The phenylpropanoid biosynthesis and glutathione metabolism pathways were induced only in CR, as confirmed by high levels of lignification over the whole stele in CR roots six days after Rs infection. At the same time, Rs infection greatly increased the concentrations of chlorogenic acid and quercetin derivatives in CG roots as it was detected using ultra-performance liquid chromatography − tandem mass spectrometry. Characteristic increases in the expression of MAP kinase signalling pathway genes and in the concentrations of jasmonic, salicylic, abscisic and indoleacetic acid were measured in DES roots. These results indicate different Rs defence mechanisms in the two resistant potato cultivars and a different response to Rs infection in the susceptible cultivar.

Transcriptional alterations of the resistant potato genotype ‘Cruza 148’ in response to Ralstonia solanacearum infection

“…In contrast, Jose et al. (2023) found that plant–pathogen interactions pathway was downregulated in ‘Cruza 148’ after pathogen infection. The difference could be because the plants were grown under different growth conditions (cocoa peat plugs vs in vitro plants).…”

Functional and evolutionary comparative analysis of the DIR gene family in Nicotiana tabacum L. and Solanum tuberosum L.

“…To analyze the dynamic expression profiles of StDIR genes in response to Ras infection in potato, the transcriptome data obtained from potato roots (GSE211973) under the infection of Ras were analyzed (Additional file 7: Table S7 ) [ 27 ]. The results unveiled distinct variations in the expression patterns of DIR genes among potato cultivars, notably the resistant CG and CR cultivars and the sensitive DES cultivar (Fig.…”

“…To investigate the response of NtDIR and StDIR genes to pathogen infection, the transcriptome data during pathogen infection was analyzed. Using the NCBI database ( https://www.ncbi.nlm.nih.gov/geo/ ), the FPKM (Fragments Per Kilobase of transcript per Million mapped reads) value of NtDIR genes under infection of P. nicotianae were extracted from GSE168854 [ 23 ], and the FPKM value of StDIR genes under the infection of Ras were extracted from GSE211973 [ 27 ].…”