Tight repulsion linkage between Sr36 and Sr39 was revealed by genetic, cytogenetic and molecular analyses
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The shortening of Aegilops speltoides segment did not facilitate recombination between stem rust resistance genes Sr36 and Sr39 . Robustness of marker rwgs28 for marker-assisted selection of Sr39 was demonstrated.
Stem rust resistance genes Sr39 and Sr36 were transferred from Aegilops speltoides and Triticum timopheevii, respectively, to chromosome 2B of wheat. Genetic stocks RL6082 and RWG1 carrying Sr39 on a large and a shortened Ae. speltoides segments, respectively, and the Sr36-carrying Australian wheat cultivar Cook were used in this study. This investigation was planned to determine the genetic relationship between these genes. Stem rust tests on F3 populations derived from RL6082/Cook and RWG1/Cook crosses showed tight repulsion linkage between Sr39 and Sr36. The genomic in situ hybridization analysis of heterozygous F3 family from the RWG1/Cook population showed that the translocated segments do not overlap. Meiotic analysis on the F1 plant from RWG1/Cook showed two univalents at the metaphase and anaphase stages in a majority of the cells indicating absence of pairing. Since meiotic pairing has been reported to initiate at the telomere, pairing and recombination may be inhibited due to very little wheat chromatin in the distal end of the chromosome arm 2BS in RWG1. The Sr39-carrying large Ae. speltoides segment transmitted preferentially in the RL6082/Cook F3 population, whereas the Sr36-carrying T. timopheevii segment over-transmitted in the RWG1/Cook cross. Genotyping with the co-dominant Sr39- and Sr36-linked markers rwgs28 and stm773-2, respectively, matched the phenotypic classification of F3 families. The RWG1 allele amplified by rwgs28 was diagnostic for the shortened Ae. speltoides segment and alternate alleles were amplified in 29 Australian cultivars. Marker rwgs28 will be useful in marker-assisted pyramiding of Sr39 with other genes.
KeywordsWheat Cultivar Rust Resistance Stem Rust Chinese Spring Rust Resistance Gene
The authors are grateful to GRDC Australia and NARO-Uganda for funding this study. We thank Dr Hanif Miah for the excellent technical support.
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Conflict of interest
All authors have read the manuscript and do not have any conflict of interest.
- Flemmig EL (2012) Molecular markers to deploy and characterize stem rust resistance in wheat. PhD Thesis, North Carolina State University, USA. http://repository.lib.ncsu.edu/ir/bitstream/1840.16/8947/1/etd.pdf. Accessed 25 Feb 2016
- Jin Y, Singh RP, Ward RW, Wanyera R, Kinyua M, Njau P, Fetch T Jr, Pretorius ZA, Yahyaoui A (2007) Characterization of seedling infection types and adult plant infection responses of monogenic Sr gene lines to race TTKS of Puccinia graminis f. sp. tritici. Plant Dis 91:1096–1099CrossRefGoogle Scholar
- Joshi LM, Palmer LT (1973) Epidemiology of stem, leaf and stripe rusts of wheat in northern India. Plant Dis Reptr 57:8–12Google Scholar
- Leonard KJ (2001) Stem rust-future enemy? In stem rust of wheat: from ancient enemy to modern foe. In: Peterson PD (ed). APS Press, St. Paul, pp 119–146Google Scholar
- Liu W, Rouse M, Friebe B, Jin Y, Gill B, Pumphrey MO (2011) 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. Chromosome Res 19:669–682CrossRefPubMedGoogle Scholar
- Mago R, Zhang P, Bariana HS, Verlin DC, Bansal UK, Ellis JG, Dundas IS (2009) Development of wheat lines carrying stem rust resistance gene Sr39 with reduced Aegilops speltoides chromatin and simple PCR markers for marker-assisted selection. Theor Appl Genet 119:1441–1450CrossRefPubMedGoogle Scholar
- McIntosh RA, Arts CJ (1996) Genetic linkage of the Yr1 and Pm4 genes for stripe rust and powdery mildew resistance in wheat. Euphytica 89:401–403Google Scholar
- McIntosh RA, Luig NH (1973) Recombination between genes for reaction to P. graminis at or near the Sr9 locus. In ‘Proc 4th Int Wheat Genetics Symp. In: Sears ER, Sears LMS (eds). Agricultural Experiment Station, University of Missouri, Missouri, pp 425–432Google Scholar
- McIntosh RA, Yamazaki Y, Dubcovsky J, Rogers J, Morris C, Appels R, Xia XC (2013) Catalogue of Gene Symbols for Wheat. 12th International Wheat Genetics Symposium, 8–13 September 2013, Yokohama, JapanGoogle Scholar
- Nagarajan S, Joshi LM (1975) An historical account of wheat rust epidemics in India and their significance. Cereal Rust Bull 3:29–33Google Scholar
- Qi LL, Pumphrey MO, Friebe B, Zhang P, Qian C, Bowden RL, Rouse MN, Jin Y, Gill BS (2011) 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. Theor Appl Genet 123:159–167CrossRefPubMedGoogle Scholar
- Sai Prasad SV, Singh SK, Ambati VD, Prakasha TL, Singh JB, Dubey VG, Kantwa SR, Mishra AN (2014) Introgression of stem rust resistance gene Sr36 into durum wheat back ground using marker assisted backcross breeding. J Wheat Res 6:21–24Google Scholar
- Singh RP, Hodson DP, Jin Y, Huerta-Espino J, Kinyua M, 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 Res 54:1–13Google Scholar
- Stakman EC, Harrar JG (1957) Principles of plant pathology. Ronald Press, New YorkGoogle Scholar
- Watson IA (1981) Wheat and its rust parasites in Australia. In wheat science-today and tomorrow. In: Evans LT, Peacock WJ (eds). Cambridge University Press, London, pp 129–147Google Scholar
- Zadoks JC (1963) Epidemiology of wheat rusts in Europe. FAO Plant Prot Bull 13:97–108Google Scholar
- Zadoks JC (2008) On the political economy of plant disease epidemics: Capita selecta in historic epidemiology. Academic Publishers, WageningenGoogle Scholar