# Identification of candidate host-specificity genes in Exserohilum turcicum using comparative genomics and transcriptomics

## TL;DR

This study identifies genes in a fungus that may determine which plant host it infects, using genome and gene expression data.

## Contribution

The study identifies candidate host-specificity genes in Exserohilum turcicum through comparative genomics and transcriptomics.

## Key findings

- Genome assemblies of sorghum- and maize-specific E. turcicum strains revealed ten inversions and three translocations.
- Candidate host-specificity genes were identified by integrating genome comparisons, annotations, and transcriptome data.
- RNA sequencing showed gene expression differences between isolates in their respective host plants.

## Abstract

Exserohilum turcicum causes northern corn leaf blight and sorghum leaf blight. While the same species cause disease in both crops, the strains are host-specific. Here, we report the sequence and de novo annotated assemblies of one sorghum- and one maize-specific E. turcicum strain. The strains were sequenced using the PacBio Sequel II system. The total genome length for both assemblies was between 44 and 45 Mb with N50 of ∼2.5 Mb. Ninety-eight percent of the Benchmarking Universal Single-Copy Orthologs (BUSCO) for both assemblies had complete status. The estimated number of genes was 11,762 and 12,029 in the sorghum- and maize-specific isolates, respectively. Funannotate, EffectorP, SignalP, and transcriptome data were used to create functional annotation of each genome. The whole-genome comparison identified ten large-scale inversions and three translocations between the maize- and sorghum-specific strains, along with homologous genes and gene duplications. RNA was sequenced from the maize- and sorghum-specific isolate 10 days post-inoculation in maize and sorghum and from axenic cultures. Gene expression data from planta and axenic growth experiments were compared for each strain. Candidate host-specificity genes were identified by combining results from whole-genome comparison, synteny analysis, gene annotations, and transcriptome data. Overall, this study identified several candidate host-specificity genes that provide insights into E. turcicum interaction with its hosts.