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[学术文献 ] Identification of wheat stem rust resistance genes in wheat cultivars from Hebei province, China 进入全文
Frontiers
Wheat stem rust is caused by Puccinia graminis f. sp. tritici. This major disease has been effectively controlled via resistance genes since the 1970s. The appearance and spread of new races of P. graminis f. sp. tritici (eg., Ug99, TKTTF, and TTRTF) have renewed the interest in identifying the resistance gene and breeding cultivars resistant to wheat stem rust. In this study, gene postulation, pedigree analysis, and molecular detection were used to determine the presence of stem rust resistance genes in 65 commercial wheat cultivars from Hebei Province. In addition, two predominant races 21C3CTHTM and 34MRGQM were used to evaluate the resistance of these cultivars at the adult-plant stage in 2021–2022. The results revealed that 6 Sr genes (namely, Sr5, Sr17, Sr24, Sr31, Sr32, Sr38, and SrTmp), either singly or in combination, were identified in 46 wheat cultivars. Overall, 37 wheat cultivars contained Sr31. Sr5 and Sr17 were present in 3 and 3 cultivars, respectively. Gao 5218 strong gluten, Jie 13-Ji 7369, and Kenong 1006 contained Sr24, Sr32, and Sr38, respectively. No wheat cultivar contained Sr25 and Sr26. In total, 50 (76.9%) wheat cultivars were resistant to all tested races of P. graminis f. sp. tritici in field test in 2021–2022. This study is important for breeding wheat cultivars with resistance to stem rust.
[学术文献 ] Orthologous genes Pm12 and Pm21 from two wild relatives of wheat show evolutionary conservation but divergent powdery mildew resistance 进入全文
Plant Communications
Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is a devastating disease that threatens wheat production worldwide. Pm12, which originated from Aegilops speltoides, a wild relative of wheat, confers strong resistance to powdery mildew and therefore has potential use in wheat breeding. Using susceptible mutants induced by gamma irradiation, we physically mapped and isolated Pm12 and showed it to be orthologous to Pm21 from Dasypyrum villosum, also a wild relative of wheat. The resistance function of Pm12 was validated via ethyl methanesulfonate mutagenesis, virus-induced gene silencing, and stable genetic transformation. Evolutionary analysis indicates that the Pm12/Pm21 loci in wheat species are relatively conserved but dynamic. Here, we demonstrated that the two orthologous genes, Pm12 and Pm21, possess differential resistance against the same set of Bgt isolates. Overexpression of the coiled-coil domains of both PM12 and PM21 induces cell death in Nicotiana benthamiana leaves. However, their full-length forms display different cell death-inducing activities caused by their distinct intramolecular interactions. Cloning of Pm12 will facilitate its application in wheat breeding programs. This study also gives new insight into two orthologous resistance genes, Pm12 and Pm21, which show different race specificities and intramolecular interaction patterns.
[学术文献 ] Molecular Markers and Their Applications in Marker-Assisted Selection (MAS) in Bread Wheat (Triticum aestivum L.) 进入全文
MDPI
As one of the essential cereal crops, wheat provides 20% of the calories and proteins consumed by humans. Due to population expansion, dietary shift and climate change, it is challenging for wheat breeders to develop new varieties for meeting wheat production requirements. Marker-assisted selection (MAS) has distinct advantages over conventional selection in plant breeding, such as being time-saving, cost-effective and goal-oriented. This review makes attempts to give a description of different molecular markers: sequence tagged site (STS), simple sequence repeat (SSR), genotyping by sequencing (GBS), single nucleotide polymorphism (SNP) arrays, exome capture, Kompetitive Allele Specific PCR (KASP), cleaved amplified polymorphic sequence (CAPS), semi-thermal asymmetric reverse PCR (STARP) and genotyping by target sequencing (GBTS). We also summarize some quantitative trait loci (QTL)/genes as well as their linked markers, which are potentially useful in MAS. This paper provides updated information on some markers linked to critical traits and their potential applications in wheat breeding programs.
[学术文献 ] Molecular screening of the landraces from Turkey and modern bread wheat (Triticum aestivum L.) cultivars for HMW-GS, wbm, waxy genes and Lr34 gene 进入全文
Springer
Landraces are significant genetic resources for wheat breeding as they can adapt to their regions of origin. However, for this genetic resource to be used effectively in wheat breeding, it should be screened molecularly for some functional genes. The study used 123 landraces and modern bread wheat varieties grown in Turkey. We screened the genetic materials for the wbm, waxy genes, high molecular weight glutenin subunits, and the Lr34 gene, which provides adult plant resistance to rust disease. There were three different alleles for the Glu-A1 locus, six different alleles for the Glu-B1 locus, and five different alleles for the Glu-D1 locus. For the Glu-A1 locus, a null subunit was found in 73 genotypes (59.3%) and that is the most common subunit. 7 + 8 subunit is the most common alleles (65.8%) in the Glu-B1 locus. In the Glu-D1 locus, 2 + 12 is the most common (63.4%) subunit associated with poor gluten quality, and 78 genotypes contain this subunit. When the three loci were evaluated, 23 combinations were found among all the genotypes screened. The two combinations include two new subunits (2 + 12′ and 2 + 12*) whose effects on bread quality have not yet been evaluated. Halbert and Gülümbür-Makas wheat cultivars contain the wbm gene, while six cultivars contain the Lr-34 gene. Six genotypes have only Wx-A1 and Wx-D1 alleles for waxy alleles. The results revealed that the landraces did not contain the genes screened within the scope of the study in terms of functional genes used in wheat breeding. The results indicated that we should use modern cultivars containing target genes in breeding programs when these landraces are used as the parent.
[学术文献 ] Population Genetic Analysis of a Bread Wheat Panel from Northern and Huang-Huai Agro-Ecological Regions in China 进入全文
MDPI
Bread wheat (Triticum aestivum L.) is one of the most extensively cultivated cereal crops around the world. Here, we investigated the population structure and genetic diversity of a panel mainly originated from two wheat agro-ecological regions (northern winter wheat region, NW; and the Huang-Huai River Valley’s facultative wheat region, HH) in China based on a 15K SNP array. Population genetic analysis revealed that the optimal population number (K) was three, and the three groups were roughly related to ecological regions, including NW (mainly Hebei), HH1 (Henan-Shaanxi), and HH2 (Shandong). Within HH, HH1 had a higher nucleotide diversity (π = 0.31167), minor allele frequency (MAF = 0.2663), polymorphism information content (PIC = 0.2668), and expected heterozygosity (Hexp = 0.3346) than HH2. Furthermore, our results demonstrated that genetic diversity decreases with the advancement of wheat breeding. Finally, inference of ancestry informative markers indicated that the genomes of the three pure groups from the three provinces (Hebei, Henan, and Shandong) of the two regions have genomic regions with different mosaic patterns derived from the two landrace groups. These findings may facilitate the development of wheat breeding strategies to target novel desired alleles in the future.
[学术文献 ] The wheat stem rust resistance gene Sr43 encodes an unusual protein kinase 进入全文
Nature
To safeguard bread wheat against pests and diseases, breeders have introduced over 200 resistance genes into its genome, thus nearly doubling the number of designated resistance genes in the wheat gene pool1. Isolating these genes facilitates their fast-tracking in breeding programs and incorporation into polygene stacks for more durable resistance. We cloned the stem rust resistance gene Sr43, which was crossed into bread wheat from the wild grass Thinopyrum elongatum2,3. Sr43 encodes an active protein kinase fused to two domains of unknown function. The gene, which is unique to the Triticeae, appears to have arisen through a gene fusion event 6.7 to 11.6 million years ago. Transgenic expression of Sr43 in wheat conferred high levels of resistance to a wide range of isolates of the pathogen causing stem rust, highlighting the potential value of Sr43 in resistance breeding and engineering.
