Identification of Candidate Genes and Genomic Regions Associated with Adult Plant Resistance to Stripe Rust in Spring Wheat

Abstract

Wheat stripe rust (caused by Puccinia striiformis f. sp. tritici) is a major disease that damages wheat plants and affects wheat yield all over the world. In recent years, stripe rust became a major problem that affects wheat yield in Egypt. New races appeared and caused breakdowns in the resistant genotypes. To improve resistance in the Egyptian genotypes, new sources of resistance are urgently needed. In the recent research, a set of 95 wheat genotypes collected from 19 countries, including Egypt, were evaluated for their resistance against the Egyptian race(s) of stripe rust under field conditions in the two growing seasons 2018/2019 and 2019/2020. A high genetic variation was found among the tested genotypes. Single marker analysis was conducted using a subset of 71 genotypes and 424 diversity array technology (DArT) markers, well distributed across the genome. Out of the tested markers, 13 stable markers were identified that were significantly associated with resistance in both years (p-value ≤ 0.05). By using the sequence of the DArT markers, the chromosomal position of the significant DArT markers was detected, and nearby gene models were identified. Two markers on chromosomes 5A and 5B were found to be located within gene models functionally annotated with disease resistance in plants. These two markers could be used in marker-assisted selection for stripe rust resistance under Egyptian conditions. Two German genotypes were carrying the targeted allele of all the significant DArT markers associated with stripe rust resistance and could be used to improve resistance under Egyptian conditions.

Genome-Wide Screening of Broad-Spectrum Resistance to Leaf Rust (Puccinia triticina Eriks) in Spring Wheat (Triticum aestivum L.)

“…Moreover, the high genetic diversity among genotypes facilitated the GWAS studies as plant material collected from different countries. The current population was very useful to identify alleles associated with target traits in earlier studies such as drought tolerance ( Ahmed et al, 2021 ), salt tolerance ( Hasseb et al, 2022 ), and stripe rust resistance ( Abou-Zeid and Mourad, 2021 ; Mourad et al, 2021 ). The number of genotypes in each marker set was suitable for GWAS analysis.…”

“…The identified Significant DArT markers also blasted against the wheat genome using the same database after obtaining their sequence from Diversity Arrays Technology Sequences available on https://www.diversityarrays.com/technology-and-resources/sequences/ . After blasting the 9K SNP/DArT marker sequence, the position was detected based on the chromosomal location of the marker, the highest length of the blast, the highest percentage of identity (ID%) and the lowest p -value as described in ( Mourad et al, 2021 ).…”

Disease resistance and adaptation of winter wheat lines derived from wide hybridisation under arid environments

“…The genetic background and environment play important roles in the phenotypic variation for disease resistance (Mourad et al, 2021) and defining the contribution of alien genes to grain yield (Morgun, 2016;Bhatta et al, 2019;Yang et al, 2021). The plant pathological evaluation of the genetically diverse lines has revealed a wide variability pathogenesis by powdery mildew, leaf, and yellow rusts, and Septoria leaf blotch across the years.…”

“…The correlation between resistance to the same disease in different years scored R sp = 0.42*** for powdery mildew (between 2016 and 2019 years), varied from R sp = 0.45*** to 0.71*** for leaf rust (between 2016, 2018, and 2019 years), and were R sp = 0.22** for yellow rust (between 2015 and 2016 years) and R sp = 0.31*** for Septoria leaf blotch (between 2016 and 2019 years). This may be due to changes in the racial composition of pathogen populations (Wellings, 2011;Babayants, Babayants, 2014;Soko et al, 2018;Mourad et al, 2021). Another explanation could be the presence of unidentified ineffective race specific genes for resistance.…”

“…Disease resistance and adaptation of winter wheat lines derived from wide hybridisation under arid environments note that virus diseases also cause significant crop losses (Mishchenko et al,2021). A significant deterioration of grain yield and quality causes the evolution of more pathogenic disease (Wellings, 2011;O'Driscoll et al, 2014;Soko et al, 2018;Mourad et al, 2021) in combination with global climate change (Juroszek, von Tiedemann, 2013;Lewis et al, 2018;Miedaner, Juroszek, 2021). Addressing this problem requires development of genotypes resistant to biotic factors and drought (Lopes et al, 2015;Lytvynenko, 2016b;Bhatta et al, 2019;Lyfenko et al, 2021).…”