title: Characterization of the Two-Speed Subgenomes ofFusarium graminearumReveals the Fast-Speed Subgenome Specialized for Adaption and Infection.
abstract: Fusarium head blight, caused byFusarium graminearum, is one of the most severe diseases on wheat and barley worldwide. Although the genomic data of several strains were published, the intragenomic variation ofF. graminearumwas not well characterized. Here, we sequenced three Chinese strains and conducted genome-wide comparisons. Our data revealed that all the sequenced strains were distinct from each other and over 350 genes were functionally lost in each of them. Variants of each strain were unevenly distributed in a highly conserved pattern along the chromosomes, resulting in a conserved two-speed genome. The fast subgenome has a lower GC content, shorter gene length, and higher variation of exon numbers than the slow subgenome. Genes related to interaction and pathogenicity, under positive selection, and up-regulatedin plantawere all significantly enriched in the fast subgenome. Furthermore, we found that the fast subgenome coincided with facultative heterochromatin regions that were repressed in vegetative stage but activated during infection as measured by RNA-seq and ChIP-seq data, suggesting that the fast subgenome is epigenetically regulated. Taken together, our data demonstrated thatF. graminearumhas a highly conserved two-speed genome and the fast subgenome responsible for adaption and infection is under the control of heterochromatin.
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University Yangling, China.
authors.forename: Qinhu
authors.initials: Q
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University Yangling, China.
authors.forename: Cong
authors.initials: C
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University Yangling, China.
authors.forename: Chenfang
authors.initials: C
authors.lastname: Wang
authors.affiliation: College of Plant Protection, Nanjing Agricultural University Nanjing, China.
authors.forename: Changjun
authors.initials: C
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F UniversityYangling, China; Department of Botany and Plant Pathology, Purdue University, West LafayetteIN, USA.
authors.forename: Jin-Rong
authors.initials: JR
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University Yangling, China.
authors.forename: Huiquan
authors.initials: H
authors.lastname: Liu
keywords: Fusarium head blight; genomic variation; heterochromatin; positive selection; two-speed genome