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EN
Over 100 genes of resistance to rust fungi: Puccinia recondita f. sp. tritici, (47 Lr ? leaf rust genes), P. striiformis (18 Yr ? yellow rust genes) and P. graminis f. sp. tritici (41 Sr ? stripe rust genes) have been identified in wheat (Triticum aestivum L.) and its wild relatives according to recent papers. Sixteen Lr resistance genes have been mapped using restriction fragments length polymorphism (RFLP) markers on wheat chromosomes. More than ten Lr genes can be identified in breeding materials by sequence tagged site (STS) specific markers. Gene Lrk 10, closely linked to gene Lr 10, has been cloned and its function recognized. Available markers are presented in this review. The STS, cleaved amplified polymorphic sequence (CAPS) and sequence characterized amplified regions (SCAR) markers found in the literature should be verified using Triticum spp. with different genetic background. Simple sequence repeats (SSR) markers for Lr resistance genes are now also available.
EN
Sequence tagged site (STS) markers have been developed recently to identify resistance genes in wheat. A number of wild relatives have been used to transfer resistance genes into wheat cultivars. Accessions of wild species of Triticeae: Aegilops longissima (4), Ae. speltoides (6), Ae. tauschii (8), Ae. umbellulata (3), Ae. ventricosa (3), Triticum spelta (2), T. timopheevi (3), T. boeoticum (4) and T. monococcum (1), 34 in total, were examined using PCR-STS markers for resistance genes against Puccinia recondita f.sp. tritici (Lr) and Erysiphe graminis (Pm). Additionally, a set of cv. Thatcher near-isogenic lines conferring resistance genes Lr 1, Lr 9, Lr 10, Lr 24, Lr 28, Lr 35 and Lr 37 were examined with the same procedure. Twenty-two accessions were tested using the inoculation test for resistance to Erysiphe graminis, Puccinia recondita, P. striiformis and P. graminis. The most resistant entries were those of Aegilops speltoides and Triticum timopheevi and among T. boeoticum accession #5353. Markers of all mentioned Lr resistance genes were identified in all corresponding cv. Thatcher near-isogenic lines (except Lr 35 gene marker). The following resistance gene markers were identified in wild Triticeae accessions: Lr 1 in two accessions of Ae. tauschii and one accession of Ae. umbellulata, Lr 9 in one accession of Ae. umbellulata, Lr 10 in one accession of T. spelta, Lr 28 in 11 accessions: Ae. speltoides (4), Ae. umbellulata (2), T. spelta (2) and T. timopheevi (3), Lr 37 in 3 accessions of Ae. ventricosa, Pm 1 in all 34 accessions, Pm 2 in 28 accessions, Pm 3 in all 4 accessions of T. boeoticum, 1 accession of T. spelta and 1 of T. timopheevi, and Pm 13 in 5 out of 6 accessions of Ae. speltoides. Reliability and usefulness of STS markers is discussed.
EN
Three Fusarium species: F. graminearum, F. culmorum and F. cerealis were identified in laboratory cultures and in sporodochia from spikelets of scabby wheat. SCAR (sequence characterized amplified region) primers were used to identify Fusarium species and nivalenol (NIV) and deoxynivalenol (DON) chemotypes within species in laboratory cultures and field collected heads harvested in 2006. Results from PCR analyses confirmed preliminary identifications of species on the basis of examination of macroconidia under a light microscope and identification of cultures on agar media. NIV and DON (3Ac-DON and 15Ac-DON) chemotypes were identified using PCR assay. Among samples and isolates of F. graminearum, the 15Ac-DON chemotype dominated, and among those where F. culmorum was identified, the 3Ac-DON chemotype prevailed. Only 5 of the 41 isolates of F. graminearum tested, displayed the NIV chemotype. An increase in the frequency of F. graminearum and a decrease in the frequency of F. culmorum were found during 1998 to 2006.
EN
Sequence tagged site (STS) markers for eight resistance genes against Puccinia recondita f. sp. tritici were used to screen a set of near-isogenic lines of wheat cv. Thatcher containing in total 40 different Lr genes and their alleles. Polymerase chain reaction (PCR) analysis was carried out by using STS, SCAR and CAPS primers specific for the leaf rust resistance genes Lr1, Lr9, Lr10, Lr19, Lr24, Lr28, Lr37 and Lr47. The STS, CAPS and SCAR markers linked to resistance genes Lr9, Lr10, Lr19, Lr24, Lr37 and Lr47 were found to be reliable in diverse genetic backgrounds. The amplification product of the Lr1 gene marker was detected in the susceptible cv. Thatcher and in all of the near-isogenic lines examined except Lr2a, Lr2b, Lr2c and Lr19. The sequence analysis of PCR products amplified in lines Lr1, Lr10, Lr28 and in cv. Thatcher indicated that the near-isogenic lines and cv. Thatcher contained in the targeted chromosome region an allele that differed from the original alleles corresponding to Lr1/6*Thatcher (TLR621) and susceptible Thatcher (TH621). The amplification product specific to the STS marker of the Lr1 gene was amplified in almost all Thatcher near-isogenic lines and in cv. Thatcher because their alleles possessed primer sequences identical to the original allele TLR621. The marker for the Lr28 resistance gene was identified in line Lr28, carrying gene Lr28, and in 21 other near-isogenic lines. The sequencing of PCR products specific to Lr28 and generated in lines Lr1, Lr10 and Lr28 indicated that the lines Lr1, Lr10 and Lr28 are heterozygous in this region.
EN
Thirty-seven wheat cultivars originating from seven European countries were examined by using sequence tagged site (STS) markers for seven Lr (leaf rust = brown rust) resistance genes against the fungal pathogen of wheat Puccinia recondita f. sp. tritici (Lr9, Lr10, Lr19, Lr24, Lr26 and Lr37). Additionally, 22 accessions with various Lr genes from two germplasm collections were tested. A Scar (sequence-characterized amplified region) marker for Lr24 and a CAPS (Cleaved Amplified Polymorphic Sequence) marker for Lr47 were also used to identify those genes in the wheat accessions. Each marker amplified one specific DNA fragment. Three Lr gene markers were identified in wheat cultivars (Lr10, Lr26 and Lr37). Another four markers (Lr9, Lr19, Lr24 and Lr47) were found in breeding lines carrying leaf rust resistance genes. The results were compared with leaf rust resistance gene postulations made in previous studies, based on multipathotype testing. Markers for Lr10, Lr26 and Lr37 may be useful in marker-assisted breeding.
EN
Spring wheat nursery accessions, including 18 spring wheat lines derived in CIMMYT, Mexico, and 12 spring wheat cultivars bred in Poland, along with cultivars Frontana and Sumai 3 as resistant controls, were examined for resistance to leaf rust under field conditions. Multipathotype tests with 16 different pathogen isolates were performed for postulation of Lr genes in Polish cultivars. Besides, STS markers for resistance genes Lr1, Lr9, Lr10, Lr24, Lr28, Lr37 were analysed in the studied cultivars and lines with Thatcher near-isogenic lines as positive controls. All Polish cultivars appeared to be susceptible to leaf rust. Ten of the CIMMYT nursery lines (IPG-SW: #7, 11, 14, 21, 22, 23, 27, 29, 30, 32) and cv. Frontana were resistant in the same environment and can be sources of resistance genes. Marker for the Lr10 gene was identified in 6 accessions (IPG-SW #14, 22, 23, 29, 30, 32) exhibiting resistance to leaf rust, whereas markers for Lr1 and Lr28 genes were observed in all the examined accessions. STS markers for Lr9, Lr24 and Lr37 genes were not identified in the investigated accessions.
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