De novo transcriptome assembly and analysis unveil molecular insights into Cladosporidium rot development in harvested table grapes

Abstract

Cladosporium cladosporioides is a fungal pathogen that affects various crops worldwide, including table grapes, where it causes Cladosporium rot. The molecular episodes of Cladosporium rot development are still unclear and need to be explored. More detailed knowledge of the molecular mechanisms underlying Cladosporium rot will provide upcoming developments on disease resistance and management. Here, we report RNA sequencing and transcriptomic analysis of C. cladosporioides infecting postharvest table grapes and its relationship with the grape’s defense response. High-throughput sequencing of cDNA libraries following de novo transcriptome assembly produced 70 thousand transcripts. This study is the first attempt to explore the transcriptional level changes of the fungus during Cladosporium rot development in table grapes. Our study showed that the fungus expresses huge sets of pathogenicity-related genes and families of genes encoding CAZymes, transcription factors and secretory proteins. Further, we identified genes of this fungus that facilitate nutrient uptake, metabolism and growth in grapes, which were significantly upregulated. This study provides valuable insights into the complex pathogenic mechanisms of C. cladosporioides, in which the fungi alter its transcriptome and develop adaptations to overcome the grape’s defenses and colonize table grape tissue.