A multiple resistance locus on chromosome arm 3BS in wheat confers resistance to stem rust (Sr2), leaf rust (Lr27) and powdery mildew

2011 ◽  
Vol 123 (4) ◽  
pp. 615-623 ◽  
Author(s):  
R. Mago ◽  
L. Tabe ◽  
R. A. McIntosh ◽  
Z. Pretorius ◽  
R. Kota ◽  
...  
Genome ◽  
2002 ◽  
Vol 45 (4) ◽  
pp. 737-744 ◽  
Author(s):  
Christina Neu ◽  
Nils Stein ◽  
Beat Keller

The Lr20–Sr15–Pm1 resistance locus in hexaploid wheat confers resistance to three different fungal wheat pathogens (leaf rust, stem rust, and powdery mildew). It was previously localized in the distal region of chromosome arm 7AL. As a first step towards the isolation of this complex locus, we performed molecular mapping of the Lr20 and Pm1 genes in three F2 populations. In two populations, a cluster of 8 and 12 markers, respectively, cosegregated with the resistance genes. In a third population based on a cross between a susceptible lr20 mutant and a resistant cultivar, all clustered markers were monomorphic. However, in this population the recombination frequency proximal to the Lr20 gene was up to 60 times higher, indicating that the complete genetic linkage of the clustered markers is not due to a close physical linkage of the probes but is caused by suppressed recombination. This was supported by the analysis of Triticum monococcum BAC clones where no physical linkage between cosegregating probes was observed. Suppressed recombination at the Lr20–Pm1 locus is likely the result of an alien introgression of chromatin from an unidentified wild relative species or is due to chromosomal rearrangements.Key words: wheat, leaf rust, powdery mildew, resistance, suppressed recombination.


2004 ◽  
Vol 84 (4) ◽  
pp. 1015-1023 ◽  
Author(s):  
H. J. Li ◽  
R. L. Conner ◽  
B. D. McCallum ◽  
X. M. Chen ◽  
H. Su ◽  
...  

The hard red winter wheat Tangmai 4 did not develop symptoms of infection following inoculation with powdery mildew (Erysiphe graminis DC. f. sp. tritici E. Marchal) isolates from regions of western Canada and northern China. Tangmai 4 exhibited resistance to stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & Henn.) and leaf rust (P. triticina Eriks.) races from western Canada. This wheat line was resistant to individual stripe rust (P. striiformis Westend. f. sp. tritici Eriks.) races from the U.S. and Canada. Sequential C-banding and genomic in situ hybridization (GISH), and electrophoretic analyses of high molecular weight glutenins and gliadins demonstrated that Tangmai 4 carried a pair of T1BL·1RS wheat-rye (Secale cereale L.) translocated chromosomes. Since the genes located on T1BL·1RS are no longer effective in controlling powdery mildew and the rust diseases, Tangmai 4 must carry additional genes for resistance to these diseases, which makes it a valuable resource for the improvement of resistance in wheat against these diseases. Key words: T1BL·1RS translocation, disease resistance, sequential C-banding and GISH, glutenin, gliadin


2019 ◽  
Vol 109 (10) ◽  
pp. 1751-1759
Author(s):  
Linda Tabe ◽  
Sharon Samuel ◽  
Matthew Dunn ◽  
Rosemary White ◽  
Rohit Mago ◽  
...  

The wheat Sr2 locus confers partial resistance to four biotrophic pathogens: wheat stem rust (Puccinia graminis f. sp. tritici), leaf rust (P. triticina), stripe rust (P. striiformis f. sp. tritici), and powdery mildew (Blumeria graminis f. sp. tritici). In addition, Sr2 is linked with a brown coloration of ears and stems, termed pseudo-black chaff (PBC). PBC, initially believed to be elicited by stem rust infection, was subsequently recognized to occur in the absence of pathogen infection. The current study demonstrates that the resistance response to stem rust is associated with the death of photosynthetic cells around rust infection sites in the inoculated leaf sheath. Similarly, Sr2-dependent resistance to powdery mildew was associated with the death of leaf mesophyll cells around mildew infection sites. We demonstrate that PBC occurring in the absence of pathogen inoculation also corresponds with death and the collapse of photosynthetic cells in the affected parts of stems and ears. In addition, Sr2-dependent necrosis was inducible in leaves by application of petroleum jelly or by heat treatments. Thus, Sr2 was found to be associated with cell death, which could be triggered by either biotic or abiotic stresses. Our results suggest a role for the Sr2 locus in controlling cell death in response to stress.


1985 ◽  
Vol 33 (2) ◽  
pp. 133-153 ◽  
Author(s):  
Jan Valkoun ◽  
Karl Hammer ◽  
Dagmar Kučerová ◽  
Pavel Bartoš

2017 ◽  
Vol 6 (3) ◽  
pp. 41-45
Author(s):  
Teklay A. Teferi ◽  
Muruts L. Wubshet

Barley is attacked by many diseases and hence, the study was conducted to quantify and profile barley affecting diseases for management options. The survey was based on the assessment of barley fields at 5 km interval. Results indicated that powdery mildew, leaf rust, stem rust, leaf scald, and smuts were among the important diseases in south Tigray. The prevalence of the former diseases was 60, 60, 40, 47.8, and 40%, respectively. The incidence of powdery mildew, scaled, leaf rust and stem rust was 100% in considerable fields and cultivars. The incidence of smuts was ranged from 5% to 30%. Similarly, the mean severities of powdery mildew, leaf rust, stem rust and leaf scald were 43.4, 54.5, 45 and 20%, respectively, while, smuts caused complete spike losses.  Therefore, investigating of the pathogens variability especially for rusts, powdery mildew and scald as well as developing integrated management options for all diseases is of concern.


Euphytica ◽  
2010 ◽  
Vol 176 (2) ◽  
pp. 157-166 ◽  
Author(s):  
Dan Wang ◽  
Lifang Zhuang ◽  
Ling Sun ◽  
Yigao Feng ◽  
Ziyou Pei ◽  
...  

Genetika ◽  
2008 ◽  
Vol 40 (3) ◽  
pp. 261-270 ◽  
Author(s):  
Miodrag Dimitrijevic ◽  
Sofija Petrovic ◽  
Perry Gustafson

A sample of 139 varieties of common wheat (Triticum aestivum L.), predominantly Serbian winter wheat varieties originated in the Institute of Field and Vegetable Crops in Novi Sad, has been examined for presence of 1BL/1RS wheat-rye translocation. Two genotype groups consisted of varieties possessing and lacking the translocation have been compared. Stem rust, leaf rust, powdery mildew as well as, winter hardiness were studied. The influence of 1BL/1RS translocation was also studied in a light of wheat seed storage protein (glutenin and gliadin) genetic background composition. Genotypes having the translocation appeared to be more tolerant to stem rust, and leaf rust, but more susceptible to powdery mildew. These effects were slightly modified depending on the examined genetic background, but the effect of the rye 1RS translocated chromosome arm was the main cause for the observed differences.


1967 ◽  
Vol 20 (6) ◽  
pp. 1181 ◽  
Author(s):  
RA Mcintosh ◽  
NH Luig ◽  
EP Baker

Three linked genes responsible for resistance respectively to stem rust, to leaf rust, and to powdery mildew are located on chromosome 7B of Hope wheat. The gene for stem rust resistance, operative in seedling and adult plant stages, is recessive and is designated Br17. The incompletely dominant gene for resistance to leaf rust, designated Lr14, showed 18% recombination with sr17, whilst in two different crosses recombination estimates of 6�0 and 2�5%, respectively, were obtained for the recessive gene for mildew resistance and Br17. All three genes were found to be present in a high proportion of Hope and H�44 derivatives. The gene Br 1'7 is apparently ineffective in conferring resistance to North American and pre.1954 Australian stem rust strains. Its incorporation into several cultivars selected for resistance to these strains presumably resulted from gene interactions or linkage with genes for resistance to other diseases.


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