Reference Assembly and Annotation of the Pyrenophora teres f. teres Isolate 0-1.

Abstract

Pyrenophora teres f. teres, the causal agent of net form net blotch (NFNB) of barley, is a destructive pathogen in barley-growing regions throughout the world. Typical yield losses due to NFNB range from 10 to 40%; however, complete loss has been observed on highly susceptible barley lines where environmental conditions favor the pathogen. Currently, genomic resources for this economically important pathogen are limited to a fragmented draft genome assembly and annotation, with limited RNA support of the P. teres f. teres isolate 0-1. This research presents an updated 0-1 reference assembly facilitated by long-read sequencing and scaffolding with the assistance of genetic linkage maps. Additionally, genome annotation was mediated by RNAseq analysis using three infection time points and a pure culture sample, resulting in 11,541 high-confidence gene models. The 0-1 genome assembly and annotation presented here now contains the majority of the repetitive content of the genome. Analysis of the 0-1 genome revealed classic characteristics of a “two-speed” genome, being compartmentalized into GC-equilibrated and AT-rich compartments. The assembly of repetitive AT-rich regions will be important for future investigation of genes known as effectors, which often reside in close proximity to repetitive regions. These effectors are responsible for manipulation of the host defense during infection. This updated P. teres f. teres isolate 0-1 reference genome assembly and annotation provides a robust resource for the examination of the barley–P. teres f. teres host–pathogen coevolution.