Rye stem rust is a reservoir of diversity and virulence for wheat stem rust
- 1United States Department of Agriculture
Abstract
Sexual populations of the stem rust pathogen (Puccinia graminis or Pg) are producing new race types globally. An analysis of 385 Pg genomes (204 from this study) illuminated international migration and admixture events. Within Kazakhstan, a novel and diverse sexual clade of P. graminis is described. An analysis of the highly divergent mating type homeodomain (HD) locus found that the 75 Kazakhstan isolates had 41 different HD haplotypes, out of a total of 99 P. graminis HD haplotypes found globally. Kazakh isolates share HD haplotypes with isolates in clade 1 (Ug99), 3-B (TTRTF), and 4 (TKTTF). There are 148 unique combinations of HD locus haplotypes within the 385 isolates. Rye (Pgs) and wheat (Pgt) stem rust share multiple HD locus haplotypes and have conserved pheromone receptors and precursors, while oat stem rust (Pga) does not. Virulent alleles for AvrSr13, AvrSr22, and AvrSr50 in Pgt are frequently derived from admixture with Pgs. Pgs also contains virulent effectors for AvrSr33, AvrSr62, and AvrSr27. Pgt isolates virulent on Sr31, such as Ug99 and isolates from Spain, have genetic links to North American Pgs isolates which are present in regions of the United States where barberry is common.
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BibTeX
@misc{ingram2026stem,
title = {{Rye stem rust is a reservoir of diversity and virulence for wheat stem rust}},
author = {T. W. Ingram and M. L. Veregge and P. Olivera Firpo and Y. Jin and A. Akhunova and E. Akhunov and M. N. Rouse and M. J. Moscou},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.12.758526},
url = {https://www.biorxiv.org/content/10.64898/2026.10.12.758526v1},
note = {CC0},
}
RIS
TY - UNPB
TI - Rye stem rust is a reservoir of diversity and virulence for wheat stem rust
AU - T. W. Ingram
AU - M. L. Veregge
AU - P. Olivera Firpo
AU - Y. Jin
AU - A. Akhunova
AU - E. Akhunov
AU - M. N. Rouse
AU - M. J. Moscou
PY - 2026
DA - 2026/10/12
PB - bioRxiv
DO - 10.64898/2026.10.12.758526
UR - https://www.biorxiv.org/content/10.64898/2026.10.12.758526v1
AB - Sexual populations of the stem rust pathogen (Puccinia graminis or Pg) are producing new race types globally. An analysis of 385 Pg genomes (204 from this study) illuminated international migration and admixture events. Within Kazakhstan, a novel and diverse sexual clade of P. graminis is described. An analysis of the highly divergent mating type homeodomain (HD) locus found that the 75 Kazakhstan isolates had 41 different HD haplotypes, out of a total of 99 P. graminis HD haplotypes found globally. Kazakh isolates share HD haplotypes with isolates in clade 1 (Ug99), 3-B (TTRTF), and 4 (TKTTF). There are 148 unique combinations of HD locus haplotypes within the 385 isolates. Rye (Pgs) and wheat (Pgt) stem rust share multiple HD locus haplotypes and have conserved pheromone receptors and precursors, while oat stem rust (Pga) does not. Virulent alleles for AvrSr13, AvrSr22, and AvrSr50 in Pgt are frequently derived from admixture with Pgs. Pgs also contains virulent effectors for AvrSr33, AvrSr62, and AvrSr27. Pgt isolates virulent on Sr31, such as Ug99 and isolates from Spain, have genetic links to North American Pgs isolates which are present in regions of the United States where barberry is common.
ER -