Identifcation of genotypescarriers of resistance to tan spot Ptr ToxA and Ptr ToxB of Pyrenophora tritici-repentis in common wheat collection

Abstract

Pyrenophora tritici-repentis(Ptr) is the causative agent of tan spot, one of the yield limiting diseases of wheat, rapidly increasing in wheat growing countries including Kazakhstan. The aim of this study was the identifcation of wheat genotypes with resistance to Ptr race 1 and race 5 and their host­selective effectors (toxins) Ptr ToxA and Ptr ToxB. A common wheat collection of 41 accessions (38 experimental and 3 controls) was characterized using the molecular markersXfcp623andXBE444541, diagnostic for theTsn1andTsc2genes conferring sensitivity to fungal toxins. The coincidence of the markerXBE444541with resistance to race 5 was 92.11 %, and with Ptr ToxB, 97.37 %. Genotyping results using the markerXfcp623confrmed the expected response to Ptr ToxA; the presence/absence of the markerXfcp623completely (100 %) coincided with sensitivity/resistance to race 1 and Ptr ToxA. This demonstrates the reliability of the diagnostic markerXfcp623for identifying wheat genotypes with resistance to the fungus and insensitivity to Ptr ToxA. The study of the reaction of wheat germplasm to the fungal inoculation and toxin infltration showed that out of 38 genotypes analyzed 30 (78 %) exhibited resistance to both race 1 and race 5, and insensitivity to toxins Ptr ToxA and ToxB. Of most signifcant interest are eight wheat genotypes that showed resistance/insensitivity both to the two races and two toxins. The results of phenotyping were reconfrmed by the molecular markers used in this study. Sensitivity to Ptr ToxB is not always correlated with susceptibility to race 5 and is dependent on the host’s genetic background of the wheat genotype, i. e. on a specifc wheat genotype. The results of the study are of interest for increasing the efciency of breeding based on the elimination of the genotypes with the dominant allelesTsn1andTsc2sensitive to the toxins Ptr ToxA and ToxB. The genotypes identifed will be used in wheat breeding for resistance to tan spot.

Phytopathological screening and molecular marker analysis of wheat germplasm from Kazakhstan and CIMMYT for resistance to tan spot

“…It was located in intron 5 of the locus in position 4901…5280 (Faris et al, 2010). The reliability of the diagnostic marker Xfcp623 for identifying wheat genotypes with resistance to the fungus and insensitivity to Ptr ToxA was shown in some studies (Karelov et al, 2015;Kokhmetova et al, 2017Kokhmetova et al, , 2018Mironenko et al, 2017). Taking into consideration the higher efficiency of the Xfcp623 marker, wheat germplasm in our study were genotyped with this marker.…”

“…Studies on the racial composition of P. tritici-repentis in Kazakhstan indicate the necessity to identify the wheat germplasm resistant to the prevailing races of the disease among promising lines and wheat varieties cultivated in Kazakhstan. The results of previous studies indicate the possibility of postulating recessive alleles of genes for resistance to P. tritici-repentis toxins using molecular markers (Kokhmetova et al, 2017(Kokhmetova et al, , 2018.…”

Pyrenophora tritici-repentis population structure in the Republic of Kazakhstan and identification of wheat germplasm resistant to tan spot

“…One of the main reasons for the reduction in yield of wheat in Kazakhstan are the diseases with airborne infection. Dominant position as a part of the pathogenic complex of wheat in the south and south-east of Kazakhstan took rusts (yellow, stem and leaf rust) (Kokhmetova et al, 2011(Kokhmetova et al, , 2016b(Kokhmetova et al, , 2018bRsaliyev A.S., Rsaliyev Sh.S., 2018), as well as leaf spot di seases (tan spot and Septoria) (Kokhmetova et al, 2017(Kokhmetova et al, , 2018a(Kokhmetova et al, , 2019.…”

Genetic Variability of Perspective Btreeding Material of Spring Bread Wheat for Resistance to Leaf Rust in Russia and Kazakhstan

“…Developing high yielding and leaf rust, stripe rust and stem rust resistant cultivars is an important objective of winter and spring wheat (Triticum aestivum L.) improvement programs in Central and West Asia [4][5][6][7][8]. Production of wheat in Kazakhstan is being constrained also by leaf spotting diseases, including tan spot, caused by Pyrenophora tritici-repentis [9][10][11][12][13] and common bunt, caused by Tiletia caries [14]. In the West Siberian and Ural regions of the Russian Federation, bordering Northern Kazakhstan, spring soft wheat (Triticum aestivum) is the leading grain crop.…”