Diagnostic and co-dominant PCR markers for wheat stem rust resistance genes Sr25 and Sr26
- 740 Downloads
Wheat stem rust, caused by Puccinia graminis f. sp. tritici, is one of the most destructive diseases of wheat. A new race of the pathogen named TTKSK (syn. Ug99) and its derivatives detected in East Africa are virulent to many designated and undesignated stem rust resistance genes. The emergence and spread of those races pose an imminent threat to wheat production worldwide. Genes Sr25 and Sr26 transferred into wheat from Thinopyrum ponticum are effective against these new races. DNA markers for Sr25 and Sr26 are needed to pyramid both genes into adapted germplasm. The previously published dominant markers Gb for Sr25 and Sr26#43 for Sr26 were validated with eight wheat lines with or without Sr25 or Sr26. We tested six published STS (sequence tagged site) markers amplifying diagnostic bands of Th. ponticum. Marker BF145935 consistently amplified well and can be used as a co-dominant marker for Sr25. Among 16 STS markers developed from wheat ESTs mapped to deletion bin 6AL8-0.90-1.00, none was co-dominant for tagging Sr26. However, five 6A-specific markers were identified. Multiplex PCR with marker Sr26#43 and 6A-specific marker BE518379 can be used as a co-dominant marker for Sr26. The co-dominant markers for Sr25 and Sr26 were validated with 37 lines with known stem rust resistance genes. A diverse set of germplasm consisting 170 lines from CIMMYT, China, USA and other counties were screened with the co-dominant markers for Sr25 and Sr26. Five lines with the diagnostic fragment for Sr25 were identified, and they all have ‘Wheatear’ in their pedigrees, which is known to carry Sr25. None of the 170 lines tested had Sr26, as expected.
KeywordsStem Rust Wheat Line Rust Resistance Gene Marker Genotype Stem Rust Resistance Gene
This study is a part of the Durable Rust Resistance in Wheat Project funded by the Bill and Melinda Gates Foundation. We would like to thank Drs. Zhonghu He, Ian S. Dundas for providing Chinese wheat lines and the Sr26-containing lines with shortened alien segment used in this study, and Jennifer A. Gee for her technical support in the lab.
- Cauderon Y, Saigne B, Dauge M (1973) The resistance to wheat rusts of Agropyron intermedium and its use in wheat improvement. In: Sears ER, Sears LMS (eds) Proceedings of the 4th international wheat genetics symposium, Columbia, Missouri, USA, pp 401–407Google Scholar
- Knott DR (1961) The inheritance of rust resistance VI. The transfer of stem rust resistance from Agropyron elongatum to common wheat. Can J Plant Sci 41:109–123Google Scholar
- Knott DR (1980) Mutation of a gene for yellow pigment linked to Lr19 in wheat. Can J Genet Cytol 22:651–654Google Scholar
- Martin RH (1971) Eagle—a new wheat variety. Agric Gaz NSW 82:206–207Google Scholar
- McIntosh RA, Wellings CR, Park RF (1995) Wheat rust: an atlas of resistance genes. CSIRO, AustraliaGoogle Scholar
- Qi LL, Echalier B, Chao S, Lazo GR, Butler GE, Anderson OD, Akhunov ED, Dvorak J, Linkiewicz AM, Ratnasiri A, Dubcovsky J, Bermudez-Kandianis CE, Greene RA, Kantety R, La Rota CM, Munkvold JD, Sorrells SF, Sorrells ME, Dilbirligi M, Sidhu D, Erayman M, Randhawa HS, Sandhu D, Bondareva SN, Gill KS, Mahmoud AA, Ma XF, Miftahudin GustafsonJP, Conley EJ, Nduati V, Gonzalez-Hernandez JL, Anderson JA, Peng JH, Lapitan NLV, Hossain KG, Kalavacharla V, Kianian SF, Pathan MS, Zhang DS, Nguyen HT, Choi DW, Fenton RD, Close TJ, McGuire PE, Qualset CO, Gill BS (2004) A chromosome bin map of 16,000 expressed sequence tag loci and distribution of genes among the three genomes of polyploid wheat. Genetics 168:701–712CrossRefPubMedGoogle Scholar
- Rozen S, Skaletsky HJ (2000) Primer3 on the WWW for general users and for biologist programmers. In: Krawetz S, Misener S (eds) Bioinformatics methods, protocols: methods in molecular biology. Humana Press, Totowa, pp 365–386Google Scholar
- Sears ER (1966) Nullisomic-tetrasomic combination in hexaploid wheat. In: Riley R, Lewis KR (eds) Chromosome manipulation and plant genetics. Oliver and Boyd, Edinburgh, pp 29–45Google Scholar
- Sharma D, Knott DR (1966) The transfer of leaf rust resistance from Agropyron to Triticum by irradiation. Can J Genet Cytol 8:137–143Google Scholar
- Singh RP, Hodson DP, Jin Y, Huerta-Espino J, Kinyua MG, Wanyera R, Njau P, Ward RW (2006) Current status, likely migration and strategies to mitigate the threat to wheat production from race Ug99 (TTKS) of stem rust pathogen. CAB Rev Perspect Agric Vet Sci Nutr Nat Resour 1(054):13Google Scholar
- The TT, Latter BDH, McIntosh RA, Ellison FW, Brennan PS, Fisher J, Hollamby GJ, Rathjen AJ, Wilson RE (1988) Grain yields of near isogenic lines with added genes for stem rust resistance. In: Miller TE, Koebner RMD (eds) Proceedings of the 7th international wheat genetics symposium. Bath Pres, Bath, pp 901–909Google Scholar