Alignment of Genetic and Physical Maps of Gibberella zeae

Abstract

We previously published a genetic map of Gibberella zeae (Fusarium graminearum sensu lato) based on a cross between Kansas strain Z-3639 (lineage 7) and Japanese strain R-5470 (lineage 6). In this study, that genetic map was aligned with the third assembly of the genomic sequence of G. zeae strain PH-1 (lineage 7) using seven structural genes and 108 sequenced amplified fragment length polymorphism markers. Several linkage groups were combined based on the alignments, the nine original linkage groups were reduced to six groups, and the total size of the genetic map was reduced from 1,286 to 1,140 centimorgans. Nine supercontigs, comprising 99.2% of the genomic sequence assembly, were anchored to the genetic map. Eight markers (four markers from each parent) were not found in the genome assembly, and four of these markers were closely linked, suggesting that >150 kb of DNA sequence is missing from the PH-1 genome assembly. The alignments of the linkage groups and supercontigs yielded four independent sets, which is consistent with the four chromosomes reported for this fungus. Two proposed heterozygous inversions were confirmed by the alignments; otherwise, the colinearity of the genetic and physical maps was high. Two of four regions with segregation distortion were explained by the two selectable markers employed in making the cross. The average recombination rates for each chromosome were similar to those previously reported for G. zeae. Despite an inferred history of genetic isolation of lineage 6 and lineage 7, the chromosomes of these lineages remain homologous and are capable of recombination along their entire lengths, even within the inversions. This genetic map can now be used in conjunction with the physical sequence to study phenotypes (e.g., fertility and fitness) and genetic features (e.g., centromeres and recombination frequency) that do not have a known molecular signature in the genome.

Genetic Diversity and Fitness of Fusarium graminearum Populations from Rice in Korea

“…graminearum interaction (32,38). This apparent difference may be due to differences between strains of lineage 6 and lineage 7, in which case it should be segregating in the mapping population of Jurgenson et al (16) and could be readily localized on the physical map of F. graminearum (18) as either a single gene or as a series of quantitative trait loci (8). The difference also could be due to differences in host composition (rice versus maize or wheat) or to environmental conditions, e.g., temperature, humidity, and light, that occur when perithecia are initiated.…”

Development of a Conditional Gene Expression System Using a Zearalenone-Inducible Promoter for the Ascomycete Fungus Gibberella zeae

“…Fungi have a recognition process called vege- (10), and alignment between genetic and physical maps (13) in G. zeae are currently available and would allow for the identification of vic genes in this fungus. After identifying vic genes, coexpression of these genes from different vegetative compatibility groups is necessary for understanding the entire process that is triggered by vic.…”

Deoxynivalenol Biosynthesis-Related Gene Expression During Wheat Kernel Colonization by Fusarium graminearum

“…In F. graminearum, 12 biosynthetic genes are found in a core cluster on chromosome 2, with three additional genes (Tri1, Tri101, and Tri15) located elsewhere (chromosomes 1, 4, and 3, respectively) (28). The sequenced strain of F. graminearum, PH-1, lacks functional Tri13 and Tri7, leading to the production of DON and the concomitant inability to produce NIV (20,29).…”