scholarly journals Development and Characterization of Expressed Sequence Tag-Derived Microsatellite Markers for the Wheat Stem Rust Fungus Puccinia graminis f. sp. tritici

2009 ◽  
Vol 99 (3) ◽  
pp. 282-289 ◽  
Author(s):  
S. Zhong ◽  
Y. Leng ◽  
T. L. Friesen ◽  
J. D. Faris ◽  
L. J. Szabo
Keyword(s):  
Ssr Markers ◽  
Stem Rust ◽  
Expressed Sequence Tag ◽  
Rust Fungus ◽  
Draft Genome ◽  
Puccinia Graminis ◽  
Wheat Stem Rust ◽  
Ssr Loci ◽  
Expressed Sequence

Puccinia graminis f. sp. tritici is the causal agent of stem rust disease in wheat. The rust fungus has caused devastating disease epidemics throughout history and is still posing a potential threat to wheat production in some regions of the world due to the appearance of new races. To develop microsatellite or simple sequence repeat (SSR) markers for use in population genetics studies, a total of 60,579 expressed sequence tag (EST) sequences (reads) generated from P. graminis f. sp. tritici were screened for tandemly repeated di- and tri-nucleotide units using a bioinformatics approach and 708 unisequences containing putative SSR loci with six or more repeat units were identified. Flanking primers were designed for 384 unique SSR loci, which mapped to different locations of the draft genome sequence of the fungus. Of the 384 primer pairs tested, 72 EST-SSR markers were eventually developed, which showed polymorphism among 19 isolates of P. graminis f. sp. tritici and 4 isolates of P. graminis f. sp. secalis evaluated. Thirty-two of the SSR loci were also evaluated in three other rust fungi (P. triticina, P. hordei, and P. coronata f. sp. hordei) for cross-species transferability. These SSR markers derived from ESTs will be useful for characterization of population structures and for gene mapping in P. graminis.

scholarly journals Characterization of Wheat Monogenic Lines with Known Sr Genes and Wheat Lines with Resistance to the Ug99 Race Group for Resistance to Prevalent Races of Puccinia graminis f. sp. tritici in China

Plant Disease ◽  
2020 ◽  
Vol 104 (7) ◽  
pp. 1939-1943
Author(s):  
Xian Xin Wu ◽  
Qiu Jun Lin ◽  
Xin Yu Ni ◽  
Qian Sun ◽  
Rong Zhen Chen ◽  
...  
Keyword(s):  
Food Security ◽  
Stem Rust ◽  
Adult Plant ◽  
Puccinia Graminis ◽  
Wheat Cultivars ◽  
Wheat Stem Rust ◽  
Wheat Improvement ◽  
Wheat Lines ◽  
Sr Genes

Wheat stem rust, caused by Puccinia graminis f. sp. tritici, is one of the most serious fungal diseases in wheat production, seriously threatening the global supply of wheat and endangering food security. The present study was conducted to evaluate wheat monogenic lines with known Sr genes to the most prevalent P. graminis f. sp. tritici races in China. In addition, wheat lines introduced from the International Maize and Wheat improvement Center (CIMMYT) with resistance to the Ug99 race group were also evaluated with the prevalent Chinese P. graminis f. sp. tritici races. The monogenic lines containing Sr9e, Sr21, Sr26, Sr31, Sr33, Sr35, Sr37, Sr38, Sr47, and SrTt3 were effective against races 21C3CTTTM, 34C0MRGSM, and 34C3MTGQM at both seedling and adult-plant stages. In contrast, monogenic lines containing Sr6, Sr7b, Sr8a, Sr9a, Sr9b, Sr9d, Sr9f, Sr9g, Sr13, Sr16, Sr18, Sr19, Sr20, Sr24, Sr28, Sr29, and Sr34 were highly susceptible to these races at both seedling and adult-plant stages. Lines with Sr5, Sr10, Sr13, Sr14, Sr15, Sr17, Sr21, Sr22, Sr23, Sr25, Sr27, Sr29, Sr30, Sr32, Sr36, and Sr39 were resistant to one or more of the tested races. Among the 123 CIMMYT lines, 38 (30.9%) showed varying levels of susceptibility to Chinese P. graminis f. sp. tritici races. The results should be useful for breeding wheat cultivars with resistance to stem rust.

Haustoria-like branches in axenic cultures of Puccinia graminis f. sp. tritici

1969 ◽  
Vol 47 (11) ◽  
pp. 1816-1817 ◽  
Author(s):  
P. G. Williams
Keyword(s):  
Stem Rust ◽  
Rust Fungus ◽  
Puccinia Graminis ◽  
Wheat Stem Rust ◽  
Artificial Culture ◽  
Axenic Cultures

Hyphae of the wheat stem rust fungus form short, lateral projections under conditions of artificial culture that are unfavorable for saprophytic growth. It is suggested that the structures are homologous with the haustoria of intercellular rust mycelium.

scholarly journals Phenotypic and Genotypic Characterization of Race TKTTF of Puccinia graminis f. sp. tritici that Caused a Wheat Stem Rust Epidemic in Southern Ethiopia in 2013–14

2015 ◽  
Vol 105 (7) ◽  
pp. 917-928 ◽  
Author(s):  
Pablo Olivera ◽  
Maria Newcomb ◽  
Les J. Szabo ◽  
Matthew Rouse ◽  
Jerry Johnson ◽  
...  
Keyword(s):  
Stem Rust ◽  
Southern Ethiopia ◽  
Genetic Lineage ◽  
Puccinia Graminis ◽  
Wheat Stem Rust ◽  
Low Frequencies ◽  
Meteorological Model ◽  
Breeding Lines ◽  
Genetic Types

A severe stem rust epidemic occurred in southern Ethiopia during November 2013 to January 2014, with yield losses close to 100% on the most widely grown wheat cultivar, ‘Digalu’. Sixty-four stem rust samples collected from the regions were analyzed. A meteorological model for airborne spore dispersal was used to identify which regions were most likely to have been infected from postulated sites of initial infection. Based on the analyses of 106 single-pustule isolates derived from these samples, four races of Puccinia graminis f. sp. tritici were identified: TKTTF, TTKSK, RRTTF, and JRCQC. Race TKTTF was found to be the primary cause of the epidemic in the southeastern zones of Bale and Arsi. Isolates of race TKTTF were first identified in samples collected in early October 2013 from West Arsi. It was the sole or predominant race in 31 samples collected from Bale and Arsi zones after the stem rust epidemic was established. Race TTKSK was recovered from 15 samples from Bale and Arsi zones at low frequencies. Genotyping indicated that isolates of race TKTTF belongs to a genetic lineage that is different from the Ug99 race group and is composed of two distinct genetic types. Results from evaluation of selected germplasm indicated that some cultivars and breeding lines resistant to the Ug99 race group are susceptible to race TKTTF. Appearance of race TKTTF and the ensuing epidemic underlines the continuing threats and challenges posed by stem rust not only in East Africa but also to wider-scale wheat production.

Use of expressed sequence tag microsatellite markers for exploring genetic diversity in lentil and related wild species

2016 ◽  
Vol 154 (7) ◽  
pp. 1254-1269 ◽  
Author(s):  
A. SINGH ◽  
H. K. DIKSHIT ◽  
D. SINGH ◽  
N. JAIN ◽  
M. ASKI ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Ssr Markers ◽  
Wild Species ◽  
Expressed Sequence Tag ◽  
Group Method ◽  
Comparative Genomic ◽  
Pair Group ◽  
Ssr Loci ◽  
Related Wild Species ◽  
Expressed Sequence

SUMMARYExpressed sequence tag-simple sequence repeat (EST-SSR) markers were used to analyse genetic diversity among three Lens species. The SSR loci amplified successfully in wild species, with 94·82% transferability in Lens culinaris subsp. orientalis, 95·4% in Lens nigricans, 98·81% in L. culinaris subsp. odemensis, 94·82% in L. culinaris subsp. tomentosus and 96·55% in Lens ervoides. Ninety-nine alleles (average 3·41 alleles/locus) were detected by 29 SSR markers. Based on the unweighted pair group method with arithmetic mean cluster analysis, all the genotypes were grouped into three clusters at a similarity level of 0·30. The diversity analysis indicated no species-specific clustering of the wild and cultivated species. Wild species L. nigricans and L. culinaris subsp. odemensis, L. culinaris subsp. orientalis and L. ervoides were grouped in Cluster I, whereas the Mediterranean land races of L. culinaris subsp. culinaris and L. culinaris subsp. tomentosus formed a separate group in Cluster II A. Cluster II B comprised L. ervoides, L. culinaris subsp. orientalis and L. culinaris subsp. culinaris. Clusters II C, II D and II F included cultivated Indian lentil genotypes. Cluster II E comprised Indian and Mediterranean germplasm lines. Cluster II F included three early maturing germplasm lines, whereas Cluster III included only two germplasm lines. The functional annotation of SSR-containing unigenes revealed that a majority of genes were involved in an important transport-related function or were a component of metabolic pathways. A high level of polymorphism of EST-SSRs and their transferability to related wild species indicated that these markers could be used for molecular screening, map construction, comparative genomic studies and marker-assisted selection.

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