Stem rust resistance gene SrTA10171

The SrTA10171 gene was discovered in Aegilops tauschii accession TA10171 from Turkmenistan. This gene is resistant to Ug-99 related races TTKSK and TTKST. It is also confers resistance to RKQQC, QTHJC (both endemic to North America) TTTTF and TPMKC races. SrTA10171 confers a seedling stage resistance thorough a hypersensitive reaction.

SrTA10171 was transferred to hexaploid hard white winter line KS05HW14. This adapted line is resistant to soilborne wheat mosaic virus, wheat streak mosaic virus, and moderately resistant to stripe rust, but susceptible to stem rust races QTHJC, RKQQC, TPMKC, and TTKSK (1).

One of the advantages of breeding with A. tauschii genes is that it is possible to obtain homologous recombination between the D genome chromosomes of A. tauschii and Triticum aestivum. However, the hybrid F1 lines tend to produce aberrant endosperm. To avoid this problem different procedures have been designed to yield fertile plants. In the case of SrTA10171 a direct crossing technique involving inter-species crossing, embryo rescue and backcrossing to the adapted hexaploid line was used (2). Despite these difficulties, the existence of homologous recombination is an advantage compared to the transfer of large non-recombinant fragments that can include undesired genes. Other Sr genes derived from A. tauschii that are effective against TTKSK are Sr33, Sr45, Sr46, SrTA1662 and SrTA10187.

Markers for SrTA10171

SrTA10171

Olson et al. (1) developed a mapping population composed of KS05HW14, TA10171 and 107 BC2F1 recombinant lines and located SrTA10171 on the short arm of chromosome 7D. The figure on the right show the position of some proximal markers that can be useful for MAS.

Primers sequences: 

gdm88

gdm88-F       5'- TCC CAC CTT TTT GCT GTA GA -3'

gdm88-R       5'- AAG GAC AAA TCC CTG CAT GA -3'

Annealing temperature: 60°C

wmc827

wmc827-F       5'- ACG GTG ACC TCA GTG CTC AC -3'

wmc827-R       5'- ATG CTT GCC TCA GCA AAA CC -3'

Annealing temperature: 61°C

cfd30

cfd30-F       5'- AAT CGC ACA ACA ATG GTT CA -3'

cfd30-R       5'- GCC TCT CCT CTC TGC TCC TT -3'

Annealing temperature: 60°C

wmc463

wmc463-F       5'- GAT TGT ATA GTC GGT TAC CCC T -3'

wmc463-R       5'- ATT AGT GCC CTC CAT AAT TGT G -3'

Annealing temperature: 51°C

PCR conditions:

  • Denaturing step: 95°C
  • Amplification step (35 cycles):
    • 95°C, 60 sec
    • primer annealing temperature, 60 sec
    • 72°C, 2 min
  • Extension step: 72°C, 10 min

Final concentrations of the reagents used in the PCR amplification

  • 4.14 µL ddH20
  • 1.2 µL 10x reaction buffer
  • 0.45 µL 50 mM MgCl2
  • 0.96 µL 2.5 mM dNTPs
  • 1.20 µL 1 pM of forward primer with a 19 bp M-13 tail (5'-ACGACGTTGTAAAACGAC)
  • 1.00 µL 10 pM of reverse primer
  • 1.0 µL 10 pM of M-13 primer labeled with 6-FAM, VIC, PET, or NED
  • 0.1 µL (0.5 U) Taq polymerase
  • 2 µL of template DNA (30 ng/µL)

Expected products

Sizing of PCR products was performed by capillary electrophoresis using a 3730xl DNA Analyzer. The table below show the allele sizes of the markers for A. tauschii TA10171 and KS05HW14:.

Locus A. tauschii KS05HW14
Xgdm88 118 116
Xwmc827 132 171
Xcfd30 177 174
Xwmc463 156 152

The sizes reported in this table do not include the 19-bp M13 tail.

Conditions presented here should be considered only as a starting point of the PCR optimization for individual laboratories.

References

1. Introgression of stem rust resistance genes SrTA10187 and SrTA10171 from Aegilops tauschii to wheat. Olson EL, Rouse MN, Pumphrey MO, Bowden RL, Gill BS, Poland JA. In: Theoretical and Applied Genetics, 2013, 126:2477-2484. DOI: 10.1007/s00122-013-2148-z

1. Simultaneous transfer, introgression, and genomic localization of genes for resistance to stem rust race TTKSK (Ug99) from Aegilops tauschii to wheat. Olson EL, Rouse MN, Pumphrey MO, Bowden RL, Gill BS, Poland JA. . In: Theoretical and Applied Genetics, 2013, 126:1179–1188. DOI: 10.1007/s00122-013-2045-5

Tags

stem rust resistance