Transcriptome Analysis of Fusarium-Tomato Interaction Based on an Updated Genome Annotation of f. sp. Identifies Novel Effector Candidates That Suppress or Induce Cell Death in .

f. sp. () causes vascular wilt disease in tomato. Upon colonization of the host, secretes many small effector proteins into the xylem sap to facilitate infection. Besides known SIX (secreted in xylem) proteins, the identity of additional effectors that contribute to pathogenicity remains largely unexplored. We performed a deep RNA-sequencing analysis of race 2-infected tomato, used the sequence data to annotate a published genome assembly generated via PacBio SMRT sequencing of the race 2 reference strain Fol4287, and analysed the resulting transcriptome to identify effector candidates among the newly annotated genes. We examined the -infection expression profiles of all 13 genes present in race 2 and identified 27 new candidate effector genes that were likewise significantly upregulated upon infection. Using Agrobacterium-mediated transformation, we tested the ability of 22 of the new candidate effector genes to suppress or induce cell death in leaves of . One effector candidate designated , encoding a secreted guanyl-specific ribonuclease, was found to trigger cell death and two effector candidates designated and , encoding a glucanase and a secreted trypsin, respectively, were identified that can suppress -mediated cell death. Remarkably, and were also found to suppress /- and /-mediated cell death. Using the yeast secretion trap screening system, we showed that these three biologically-active effector candidates each contain a functional signal peptide for protein secretion. Our findings provide a basis for further understanding the virulence functions of effectors.