A preliminary report on the identification of SSR markers for bunt (Tilletia sp.) resistance in wheat

Abstract

Common bunt and dwarf bunt, caused by Tilletia caries (DC) Tul., T. foetida (Wallr) Liro., and T. controversa, respectively, can still cause yield and quality losses, despite the availability of effective chemical treatments. Growing resistant cultivars remains the best option for economical and environmental reasons, and is the only effective alternative in organic farming. As the durability of bunt resistance has proved to be rather poor, the pyramiding of resistance genes has been envisaged as a method of extending the life of resistance genes. Molecular markers can considerably increase the efficiency of gene pyramiding, but, because incomplete expression of both susceptibility and resistance genes makes accurate phenotyping difficult, very few markers associated with bunt resistance genes have been identified to date. This is why, at the National Agricultural Research & Development Institute Fundulea-Romania, along with the breeding program for bunt resistance, research on the possible use of molecular markers for Marker Assisted Selection (MAS) was developed. Random F 5 or F 4 lines from crosses between a Bt11 line or a bunt resistant line derived from a Triticale/2 × wheat, and susceptible parents, were phenotyped under artificial inoculation conditions, and were genotyped using primers for several markers. Preliminary results suggest that the Bt11 gene is located on chromosome 3B, and may be associated with marker loci Xbarc180, Xwmc623, Xwmc808 and Xgwm285. The gene for bunt resistance transferred from Triticale (line F00628G34-1 -possessing a 1A/1R translocation) can make MAS possible by using 1R specific markers. Although these results are preliminary, they already prove to be useful for the diversification and pyramiding of bunt resistance genes in breeding for durability of bunt resistance.

Genetic architecture of common bunt resistance in winter wheat using genome-wide association study

“…Bt4 could be located on this chromosome due to the high linkage between it and Bt6 gene [ 26 ]. The significant SNPs on chromosomes 2B and 2D could be associated with Bt1 and Bt11 which have been mapped to chromosomes 2B and 2D, respectively [ 4 , 28 ]. Some QTLs were reported to have an association with common bunt resistance on chromosome 1A [ 27 , 29 ], but no genes were mapped on this chromosome.…”

“…Seed treatments with fungicides could be used as an effective tool to manage common bunt. However, genetic resistance is a better option for reducing exposure to chemical seed treatments and could be applied in organic systems [ 4 , 5 ].…”

Mapping of common bunt resistance gene Bt9 in wheat

“…In addition, introgressions of common bunt resistance factors from rye ( Secale cereale , Martynov and Dobrotvorskaya 2003), triticale (Ciuca 2011), barley ( Hordeum vulgare , Rubiales et al 2001), Aegilops glaucum (Martynov and Dobrotvorskaya 2003), Ae. cylindrica (Galaev et al 2006), Ae.…”

“…Demeke et al 1996; Laroche et al 2000; Ciucã 2011; Singh et al 2016). Marker-assisted selection for common bunt resistance in wheat is, however, only applied for the Bt10 resistance gene (Menzies et al 2006).…”

“…Sixteen resistance genes, designated Bt1 – Bt15 and Btp , have been identified (Goates 2012 ) and further resistance sources among Ukrainian and Russian germplasm (Martynov and Dobrotvorskaya 2003 ) and gene bank accessions (Goates and Bockelman 2012 ) have been reported. In addition, introgressions of common bunt resistance factors from rye ( Secale cereale , Martynov and Dobrotvorskaya 2003 ), triticale (Ciuca 2011 ), barley ( Hordeum vulgare , Rubiales et al 2001 ), Aegilops glaucum (Martynov and Dobrotvorskaya 2003 ), Ae. cylindrica (Galaev et al 2006 ), Ae.…”