Physiological and RNA-seq analyses provide insights into the response mechanism of the Cf-10-mediated resistance to Cladosporium fulvum infection in tomato

Abstract

Based on the physiological and RNA-seq analysis, some progress has been made in elucidating the Cf-10-mediated resistance responses to C. fulvum infection in tomato. GO and KEGG enrichment analysis revealed that the DEGs were significantly associated with defense-signaling pathways like oxidation-reduction processes, oxidoreductase activity and plant hormone signal transduction. Leaf mold, caused by the fungus Cladosporium fulvum, is one of the most common diseases affecting tomatoes worldwide. Cf series genes including Cf-2, Cf-4, Cf-5, Cf-9 and Cf-10 play very important roles in resisting tomato leaf mold. Understanding the molecular mechanism of Cf gene-mediated resistance is thus the key to facilitating genetic engineering of resistance to C. fulvum infection. Progress has been made in elucidating two Cf genes, Cf -19 and Cf -12, and how they mediate resistance responses to C. fulvum infection in tomato. However, the mechanism of the Cf-10- mediated resistance response is still unclear. In the present study, RNA-seq was used to analyze changes in the transcriptome at different stages of C. fulvum infection. A total of 2,242 differentially expressed genes (DEGs) responsive to C. fulvum between 0 and 16 days post infection (dpi) were identified, including 1,501 upregulated and 741 downregulated genes. The majority of DEGs were associated with defense-signaling pathways including oxidation-reduction processes, oxidoreductase activity and plant hormone signal transduction. Four DEGs associated with plant-pathogen interaction were uniquely activated in Cf-10 tomato and validated by qRT-PCR. In addition, physiological indicators including reactive oxygen species (ROS), superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were measured at 0-21 dpi, and hormone expression [Jasmonic acid (JA) and salicylic acid (SA)] was estimated at 0 and 16 dpi to elucidate the mechanism of the Cf-10-mediated resistance response. C. fulvum infection induced the activities of POD, CAT and SOD, and decreased ROS levels. JA was determined to participate in the resistance response to C. fulvum during the initial infection period. The results of this study provide accountable evidence for the physiological and transcriptional regulation of the Cf-10-mediated resistance response to C. fulvum infection, facilitating further understanding of the molecular mechanism of Cf-10-mediated resistance to C. fulvum infection.

Comparative transcriptome analysis reveals the response mechanism of Cf-16-mediated resistance to Cladosporium fulvum infection in tomato

“…Systemic defense response mediated by resistance genes was activated during the early stage of C. fulvum infection. This finding was consistent with previous studies of other Cf genes [37][38][39]. Based on comparative transcriptome analysis, we demonstrated the resistance response to C. fulvum in Cf-16 tomato.…”

“…Furthermore, KEGG enrichment analysis indicated that most of the DEGs were classified into "Plant hormone signal transduction" and "Plant-pathogen interaction". In this preliminary comparison, more up-regulated DEGs were detected in Cf-16 compared to Cf-10 and Cf-12 tomatoes during the early stage of C. fulvum infection [38,39]. A comprehensive comparative analysis of Cf-19, Cf-12, Cf-10 and Cf-16 will provide important information for further exploration of the mechanism of Cf-gene-mediated resistance response to C. fulvum infection.…”

“…The Avr5 gene has been cloned through a combined bioinformatic and RNA-Seq-based transcriptome sequencing approach [18]. Cf-19-, Cf-12-and Cf-10-mediated resistance to C. fulvum in tomato has been characterized using cDNA-AFLP and RNA-Seq analyses [37][38][39]. However, few transcriptomic studies have examined Cf-16-mediated resistance.…”

Comparative transcriptome analysis between resistant and susceptible tomato lines uncovers the response mechanism of Cf-16-mediated resistance to Cladosporium fulvum

“…The systemic defense response of the resistance genes was activated at the early stage of C. fulvum infection. This result is consistent with the results of previous studies of other Cf genes [33][34][35]. We demonstrated that the Cf-16 tomato triggered a resistance response to the leaf pathogen C. fulvum by comparative transcriptome analysis between resistant and susceptible tomato lines using RNA-seq, and the reliability of RNA-seq data was verified by qRT-PCR analysis.…”

“…Recent advances in transcriptome sequencing (RNA-seq) have strongly accelerated research on hostpathogen interactions in plants, such as rice [27], maize [28], cucumber [29], watermelon [30] and strawberry [31]. Currently, Avr4/Cf-4-and Avr9/Cf-9-dependent defense gene expression has been completed by cDNA-amplified fragment length polymorphism (cDNA-AFLP) [32]; the Avr5 gene has been cloned by a combined bioinformatic and RNA-seq-based transcriptome sequencing approach [14]; Cf-19-mediated, Cf-12-mediated and Cf-10-mediated resistance to C. fulvum in tomato has been characterized by cDNA-AFLP and RNA-seq, respectively [33][34][35]; however, there have been few transcriptomic studies on Cf-16-mediated resistance. In this study, comparative transcriptome analysis was used to identify differentially expressed genes (DEGs) between C. fulvum-resistant and C. fulvum-susceptible tomatoes.…”