Dataset Information

Transcriptional responses to Fusarium oxysporum f. sp. lycopersici (Sacc.) Snyder & Hansen infection in three Colombian tomato cultivars.

ABSTRACT:

Background

Fusarium oxysporum f. sp. lycopersici (Fol) is a compendium of pathogenic and non-pathogenic fungal strains. Pathogenic strains may cause vascular wilt disease and produce considerable losses in commercial tomato plots. To gain insight into the molecular mechanisms mediating resistance to Fol in tomato, the aim of our study was to characterize the transcriptional response of three cultivars (CT1, CT2 and IAC391) to a pathogenic (Fol-pt) and a non-pathogenic (Fo-npt) strain of Fo.

Results

All cultivars exhibited differentially expressed genes in response to each strain of the fungus at 36 h post-inoculation. For the pathogenic strain, CT1 deployed an apparent active defense response that included upregulation of WRKY transcription factors, an extracellular chitinase, and terpenoid-related genes, among others. In IAC391, differentially expressed genes included upregulated but mostly downregulated genes. Upregulated genes mapped to ethylene regulation, pathogenesis regulation and transcription regulation, while downregulated genes potentially impacted defense responses, lipid transport and metal ion binding. Finally, CT2 exhibited mostly downregulated genes upon Fol-pt infection. This included genes involved in transcription regulation, defense responses, and metal ion binding.

Conclusions

Results suggest that CT1 mounts a defense response against Fol-pt. IAC391 exhibits an intermediate phenotype whereby some defense response genes are activated, and others are suppressed. Finally, the transcriptional profile in the CT2 hints towards lower levels of resistance. Fo-npt also induced transcriptional changes in all cultivars, but to a lesser extent. Results of this study will support genetic breeding programs currently underway in the zone.

SUBMITTER: Lopez WR

PROVIDER: S-EPMC8425103 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:In recent years, greenhouse-grown tomato (Solanum lycopersicum) plants showing vascular wilt and yellowing symptoms have been observed between 2015 and 2018 in North Carolina (NC) and considered as an emerging threat to profitability. In total, 38 putative isolates were collected from symptomatic tomatoes in 12 grower greenhouses and characterized to infer pathogenic and genomic diversity, and mating-type (MAT) idiomorphs distribution. Morphology and polymerase chain reaction (PCR) markers confirmed that all isolates were Fusarium oxysporum f. sp. lycopersici (FOL) and most of them were race 3. Virulence analysis on four different tomato cultivars revealed that virulence among isolates, resistance in tomato cultivars, and the interaction between the isolates and cultivars differed significantly (P < 0.001). Cultivar 'Happy Root' (I-1, I-2, and I-3 genes for resistance) was highly resistant to FOL isolates tested. We sequenced and examined for the presence of 15 pathogenicity genes from different classes (Fmk1, Fow1, Ftf1, Orx1, Pda1, PelA, PelD, Pep1, Pep2, eIF-3, Rho1, Scd1, Snf1, Ste12, and Sge1), and 14 Secreted In Xylem (SIX) genes to use as genetic markers to identify and differentiate pathogenic isolates of FOL. Sequence data analysis showed that five pathogenicity genes, Fmk1, PelA, Rho1, Sge1, and Ste12 were present in all isolates while Fow1, Ftf1, Orx1, Peda1, Pep1, eIF-3, Scd1, and Snf1 genes were dispersed among isolates. Two genes, Pep2 and PelD, were absent in all isolates. Of the 14 SIX genes assessed, SIX1, SIX3, SIX5, SIX6, SIX7, SIX8, SIX12, and SIX14 were identified in most isolates while the remaining SIX genes varied among isolates. All isolates harbored one of the two mating-type (MAT-1 or MAT-2) idiomorphs, but not both. The SIX4 gene was present only in race 1 isolates. Diversity assessments based on sequences of the effector SIX3- and the translation elongation factor 1-α encoding genes SIX3 and tef1-α, respectively were the most informative to differentiate pathogenic races of FOL and resulted in race 1, forming a monophyletic clade while race 3 comprised multiple clades. Furthermore, phylogeny-based on SIX3- and tef1-α gene sequences showed that the predominant race 3 from greenhouse production systems significantly overlapped with previously designated race 3 isolates from various regions of the globe.