Comparative Transcriptome Analysis of Resistant and Susceptible Tomato Lines in Response to Infection by Xanthomonas perforans Race T3

Abstract

Bacterial spot, incited by several Xanthomonas sp., is a serious disease in tomato (Solanum lycopersicum L.). Although genetics of resistance has been widely investigated, the interactions between the pathogen and tomato plants remain unclear. In this study, tanscriptomes of X. perforans race T3 infected tomato lines were compared to those of controls. An average of 7 million reads were generated with approximately 21,526 genes mapped in each sample post-inoculation at 6 h (6 HPI) and 6 days (6 DPI) using RNA-sequencing technology. Overall, the numbers of differentially expressed genes (DEGs) were higher in the resistant tomato line PI 114490 than in the susceptible line OH 88119, and the numbers of DEGs were higher at 6 DPI than at 6 HPI. Fewer genes (78 in PI 114490 and 15 in OH 88119) were up-regulated and most DEGs were down-regulated, suggesting that the inducible defense response might not be fully activated at 6 HPI. Accumulation expression levels of 326 co-up regulated genes in both tomato lines at 6 DPI might be involved in basal defense, while the specific and strongly induced genes at 6 DPI might be correlated with the resistance in PI 114490. Most DEGs were involved in plant hormone signal transduction, plant-pathogen interaction and phenylalanine metabolism, and the genes significantly up-regulated in PI 114490 at 6 DPI were associated with defense response pathways. DEGs containing NBS-LRR domain or defense-related WRKY transcription factors were also identified. The results will provide a valuable resource for understanding the interactions between X. perforans and tomato plants.

Transcriptome analysis of resistant and susceptible pepper (Capsicum annuumL.) in response toXanthomonas campestrispv.Vesicatoria

“…Furthermore, many DEGs were enriched in oxidoreductase activity (GO:0016684), acting on peroxide as acceptor (GO:0016684), peroxidase activity (GO:0004601), chitinase activity (GO:0004568), chitin binding (GO:0008061), amino sugar catabolic process (GO:0046348), amino sugar metabolic process (GO:0006040), aminoglycan catabolic process (GO:0006026), chitin catabolic process (GO:0006032), and chitin metabolic process (GO:0006030) (Fig 3; Table S6). Similar results were obtained in the previous study of tomato response to infection by Xanthomonas perforans Race 3 [24]. The expression of these defense response genes induced the synthesis of secondary metabolites, which could inhibit the spread of Xcv in peppers.…”

“…Besides, several transcriptome studies have been undertaken to identify relative genes involving in multiple biological processes such as fruit development, biotic and abiotic stress resistance [19][20][21][22]. In the case of BS stress mechanism, several transcriptomic studies have also been performed using microarrays and RNA-seq technique in tomato [23,24]. However, a genome-wide and comprehensive analysis of genes involved in BS resistance is not yet available in pepper.…”

Transcriptome analysis of Phytophthora infestans and Colletotrichum coccodes in tomato to reveal resistance mechanisms

“…Similar results were recently observed for tomato-X. perforans interaction (Du et al, 2015). The cellular component is involved in intracellular membranebounded organelle and chloroplast.…”

Transcriptome analysis clarified genes involved in resistance to Phytophthora capsici in melon

“…Among them, more DEGs were detected at 5 dpi than at 3 dpi in both lines. Similarly, in tomato inoculated with Xanthomonas perforans, there were more DEGs found at later stage (6 dpi) than at early stage (6 hpi) [21]. Based on the GO and KEGG analyses, DEGs involved in the pathways of plant hormone signal transduction, secondary metabolite biosynthesis and cell wall modification were significantly enriched.…”