Biology and Population Genetics of Cereal Rust Fungi and Host Resistance

My main research interests are in the biology and population genetics of cereal rust fungi and host resistance to rusts in wheat and barley. I conduct nationwide surveys and monitoring of the race composition and dynamics of the stem rust pathogen Puccinia graminis on small grain cereal crops, accessory hosts, and the alternate host, Berberis spp. I investigate forces causing race dynamics in the stem rust populations. I collaborate with international scientists in the investigations of the race evolution in the TTKS (or Ug99) lineage and to monitor the movement of this race group through a worldwide monitoring network. I conduct research in host resistance by identifying new sources of resistance from crop species and their wild relatives, characterizing the genetics of resistance, and developing molecular markers for stem rust resistance genes. I help wheat and barley improvement programs nationwide by providing sources of stem rust resistance and by characterizing breeding germplasm for stem rust reaction.

Ug99 and emerging virulent stem rust race

Selected Publications

in PDF format:

2013

• Identification of resistance to races of Puccinia graminis f. sp. tritici with broad virulence in Triticale (x Triticosecale).

2012

• Introgression and characterization of a goatgrass gene for a high level of resistance to Ug99 stem rust in tetraploid wheat.
• Resistance to race TTKSK of Puccinia graminis f. sp. tritici in emmer wheat.
• Identification of markers linked to the race Ug99 effective stem rust resistance gene Sr28 in wheat (Triticum aestivum L.).
• Inheritance of resistance to Ug99 stem rust in wheat cultivar Norin 40 and genetic mapping of Sr42.
• A mutagenesis-derived broad-spectrum disease resistance locus in wheat.
• Seedling resistance to stem rust race Ug99 and marker analysis for Sr2, Sr24 and Sr31 in South African wheat cultivars and lines.
• Races of Puccinia graminis f. sp. tritici with combined virulence to Sr13 and Sr9e in a field stem rust screening nursery in Ethiopia.

2011

• Genetics of resistance to race TTKSK of Puccinia graminis f. sp. tritici in Triticum monococcum.
• The emergence of Ug99 races of the stem rust fungus is a threat to world wheat production.
• Stem rust resistance in Aegilops tauschii germplasm.
• Discovery and molecular mapping of a new gene conferring resistance to stem rust, Sr53, derived from Aegilops geniculata and characterization of spontaneous translocation stocks with reduced alien chromatin.
• Sources of resistance to stem rust race Ug99 in spring wheat germplasm.
• Stem rust resistance in A-genome diploid relatives of wheat.
• A novel Robertsonian translocation event leads to transfer of a stem rust resistance gene (Sr52) effective against race Ug99 from Dasypyrum villosum into bread wheat.
• Development and characterization of wheat-Ae. searsii  Robertsonian translocations and a recombinant chromosome conferring resistance to stem rust.
• Determing the basis of nonhost resistance in rice to cereal rusts.
• Race non-specific resistance to rust diseases in CIMMYT spring wheats.
• Role of Berberis spp. as alternate hots in generating new races of Puccinia graminis and P. striiformis.
• Targeted introgression of a wheat stem rust resistance gene by DNA marker-assisted chromosome engineering.
• International surveillance of wheat rust pathogens: progress and challenges.
• An accurate DNA marker assay for stem rust resistance gene Sr2 in wheat.
• Expression of a Thatcher wheat adult plant stem rust resistance QTL on chromosome arm 2BL is enhanced byLr34
• Genetic mapping of stem rust resistance gene Sr13 in tetraploid wheat (Triticum turgidum ssp. durum L.).

2010

• Development of wheat lines having a small introgressed segment carrying stem rust resistance gene Sr22.
• Geneic maps of stem rust resistance gene Sr35 in diploid and hexaploid wheat.
• Identification of flanking markers for the stem rust resistance gene Sr6 in wheat.
• Haplotype diversity of stem rust resistance loci in uncharacterized wheat lines.
• Century-old mystery of Puccinia striiformis  life history solved with the identification of Berberis as an alternate host.
• Molecular and cytogenetic characterization of wheat introgression  lines carrying the stem rust resistance gene Sr39.
• Identification and evaluation of sources of resistance to stem rust race Ug99 in wheat.
• Registration of 'Brick' Wheat.
• Genotyping of U.S. wheat germplasm for presence of stem rust resistance genes Sr24, Sr36 and Sr1RS^Amigo
• Diagnostic and co-dominant PCR markers for wheat stem rust resistance genes Sr25 and Sr26.

2009

• Diseases which challenge global wheat production - the wheat rusts.
• Evaluation and characterization of seedling resistances to stem rust Ug99 races in wheat–alien species derivatives.
• Identification and validation of SSR markers linked to the stemrust resistance gene Sr6 on the short arm of chromosome 2D in wheat.
• Resistance to stem rust race TTKSK maps to the rpg4/Rpg5 complex of chromosome 5H of barley.
• Detection of virulence to resistance gene Sr36 within the TTKS race lineage
  of Puccinia graminis f. sp. tritici.

2008

• Genetics of leaf rust resistance in Brambling wheat.
• Molecular and cytogenetic characterization of a durum wheat - Aegilops speltoides chromosome translocation conferring resistance to stem rust
• Will stem rust destroy the world’s wheat crop?
• Detection of virulence to resistance gene Sr24 within race TTKS of Puccinia graminis f. sp. tritici.
• Inheritance of leaf rust resistance in the CIMMYT wheat Weebill 1.
• Diagnostic microsatellite markers for the detection of stem rust resistance gene Sr36 in diverse genetic backgrounds of wheat.
• New Fusarium head blight resistant spring wheat germplasm identified in the USDA National Small Grains Collection.

2007

• Microsatellite markers linked to stem rust resistance alllele Sr9a in wheat.
• Letter Code System of Nomenclature for Puccinia graminis f. sp. avenae.
• Registration of ‘Briggs’ Wheat
• Geographic distribution of stem rust resistance in wheat landraces.
• Chromosomal locations of genes for stem rust resistance in monogenic lines derived from tetraploid wheat accession ST464.
• Characterization of seedling infection types and adult plant infection responses
  of monogenic Sr gene lines to race TTKS of Puccinia graminis f. sp. tritici.
• Wheat leaf and stem rust in the United States.

2006

• Molecular cytogenetic characterization of four patrial wheat-Thinopyrum ponticum amphiploids and their reactions to Fusarium head blight, tan spot, and Stagonospora nodorum blotch.
• Current status, likely migration and strategies to mitigate the threat to wheat production from race Ug99 (TTKS) of stem rust pathogen.
• The spread of stem rust caused by Puccinia graminis f. sp. tritici, with virulence on Sr31 in wheat in eastern Africa.
• Resistance in U.S. wheat to recent eastern Africa isolates of Puccinia graminis f. sp. tritici with virulence to resistance gene Sr31.
• Registration of ‘Wendy’ wheat.

2005

• Wheat Rusts in the United States in 2004.
• Races of Puccinia graminis  identified in the United States during 2003.

2004

• Molecular mapping of the crown rust resistance gene Rpc1 in barley.
• Development of a resistance-based sensor for detection of wetness at the soil-air interface.

2003

• Molecular mapping of leaf rust resistance gene Rph5 in barley.
• Molecular mapping of the leaf rust resistance gene Rph6 in barley and its linkage relationships with Rph5 and Rph7.
• Genetic variation for Puccinia emaculata  infection in switchgrass.

2002

• Sources and genetics of crown rust resistance in barley.

2001

• Inheritance of Septoria tritici blotch resistance in winter wheat.

2000

• Molecular mapping of the leaf rust resistance gene Rph7 in barley.

1999

• Puccinia coronata var. hordei var. nov.: morphology and pathogenicity.
• Daily inoculum levels of Gibberella zeae on wheat spikes.

1998

• Chromosomal location and genetic relationship of leaf rust resistance genes Rph9 and Rph12 in barley.

1997

• Identification and mapping of a leaf rust resistance gene in barley line Q21861.

1996

• New leaf rust resistance genes in barley and their allelic and linkage relationships with other Rph genes.
• Genetics of resistance to Puccinia graminis f. sp. secalis in barley line Q21861.

1995

• Evaluation of cultivated and wild barley for resistance to pathotypes of Puccinia hordei with wide virulence.
• Identification of molecular markers linked to the stem rust resistance gene rpg4 in barley.
• Genetics of multiple disease resistance in a double-haploid population of barley.

1994

• Sources of resistance to pathotype QCC of Puccinia graminis f. sp. tritici in barley.
• Inheritance of resistance to Puccinia hordei in cultivated and wild barley.
• Inheritance of resistance to pathotypes QCC and MCC of Puccinia graminis f. sp. tritici in barley line Q21861 and temperature effects on the expression of resistance.

1993

• Linkage between leaf rust resistance genes and morphological markers in barley.
• Linkage between the Rpg1 gene for stem rust resistance and the f5 locus on barley chromosome 1.
• Pathotypes of Puccinia hordei with virulence for the barley leaf rust resistance gene Rph7 in the United States.
• Detection of the stem rust resistance gene Rpg1 in barley seedlings.

1992

• Puccinia coronata on barley.

Chromosomal Location and Genetic Relationship
of Leaf Rust Resistance Genes Rph9 and Rph12 in BarleyOther publications:

Genetic variation for Puccinia emaculata infection in switchgrass. Gustanfson, D.M., A. Boe, and Y. Jin. 2003. Crop Sci. 43:755-759.

Molecular mapping of leaf rust resistance gene Rph5 in barley. Mammadov, J.A., J.C. Zwonitzer, R.M. Biyashev, C.A. Griffey, Y. Jin, B.J. Steffenson, and M.A. Saghai Maroof. 2003. Crop Sci. 43:388-393.

Molecular mapping of the leaf rust resistance gene Rph6 in barley and its linkage relationships with Rph5 and Rph7. Zhong, S., R.J. Effertz, Y. Jin, J.D. Franckowiak, and B.J. Steffenson. 2003. Phytopathology 93:604-609.

Sources and genetics of crown rust resistance in barley. Jin, Y. and B.J. Steffenson. 2002. Phytopathology 92:1064-1067.

Publications by CDL staff available in pdf format