Sr2
is the only known durable, race non-specific adult plant stem rust resistance gene in wheat. The
Sr2
gene was shown to be tightly linked to the leaf rust resistance gene
Lr27
and to powdery ...mildew resistance. An analysis of recombinants and mutants suggests that a single gene on chromosome arm 3BS may be responsible for resistance to these three fungal pathogens. The resistance functions of the
Sr2
locus are compared and contrasted with those of the adult plant resistance gene
Lr34
.
The stem rust resistance gene Sr2 has provided broad-spectrum protection against stem rust (Puccinia graminis Pers. f. sp. tritici) since its wide spread deployment in wheat from the 1940s. Because ...Sr2 confers partial resistance which is difficult to select under field conditions, a DNA marker is desirable that accurately predicts Sr2 in diverse wheat germplasm. Using DNA sequence derived from the vicinity of the Sr2 locus, we developed a cleaved amplified polymorphic sequence (CAPS) marker that is associated with the presence or absence of the gene in 115 of 122 (95%) diverse wheat lines. The marker genotype predicted the absence of the gene in 100% of lines which were considered to lack Sr2. Discrepancies were observed in lines that were predicted to carry Sr2 but failed to show the CAPS marker. Given the high level of accuracy observed, the marker provides breeders with a selection tool for one of the most important disease resistance genes of wheat.
The short arm of rye ( Secale cereale) chromosome 1 has been widely used in breeding programs to incorporate new disease resistance genes into wheat. Using wheat-rye translocation and recombinant ...lines, molecular markers were isolated and mapped within chromosomal regions of 1RS carrying rust resistance genes Lr26, Sr31, Yr9 from 'Petkus' and SrR from 'Imperial' rye. RFLP markers previously mapped to chromosome 1HS of barley - flanking the complex Mla powdery mildew resistance gene locus - and chromosome 1DS of Aegilops tauschii - flanking the Sr33 stem rust resistance gene - were shown to map on either side of rust resistance genes on 1RS. Three non cross-hybridising Resistance Gene Analog markers, one of them being derived from the Mla gene family, were mapped within same region of 1RS. PCR-based markers were developed which were tightly linked to the rust resistance genes in 'Imperial' and 'Petkus' rye and which have potential for use in marker-assisted breeding.
Anaplasmosis and ehrlichiosis are tick-borne rickettsial diseases that cause significant economic losses in the livestock industry worldwide. Although bovine anaplasmosis is known to be endemic in ...the Philippines, epidemiological data is fragmented. Moreover, little is known about bovine ehrlichiosis in the country. In this study, the prevalence of
Anaplasma marginale
and
Ehrlichia
in cattle and water buffalo from provinces in the southern part of Luzon, Philippines, was investigated through PCR. Blood samples from 620 animals comprised of 512 cattle and 108 water buffalo and 195 tick samples were subjected to nested PCR targeting the
groESL
gene of Anaplasmataceae. Positive samples were further subjected to another nested PCR and conventional PCR to amplify the
A. marginale groEL
gene and the
Ehrlichia dsbA
gene, respectively. Selected
A. marginale
-positive samples were also subjected to nested PCR targeting the
msp5
gene. Regardless of the animal host, the overall prevalence in blood samples obtained was 51.9% for Anaplasmataceae, 43% for
A. marginale
, and 1.1% for
Ehrlichia
. No water buffalo were positive for
Ehrlichia
. Meanwhile, 15.9, 6.7, and 2% of the tick samples, all morphologically identified as
Rhipicephalus
(
Boophilus
)
microplus
, were positive for Anaplasmataceae,
A. marginale
, and
Ehrlichia
, respectively. Sequence analysis of selected
A. marginale msp5
amplicons showed that the isolates from the region share 94–98% identity to reported
A. marginale
from other countries. The phylogenetic tree showed clustering of isolates in the region and a close relationship with
A. marginale
isolates from other countries. Sequences of
Ehrlichia
amplicons from cattle and ticks were 97–100% similar to reported
Ehrlichia minasensis
isolates. This study showed the high prevalence of
A. marginale
in Luzon, Philippines, and provided the first molecular evidence of
E. minasensis
in the country.
The use of major resistance genes is the most cost-effective strategy for preventing stem rust epidemics in Australian wheat crops. The long-term success of this strategy is dependent on combining ...resistance genes that are effective against all predominant races of the pathogen, a task greatly assisted by the use of molecular markers linked to individual resistance genes. The wheat stem rust resistance genes Sr24 and Sr26 (derived from Agropyron elongatum) and SrR and Sr31 (derived from rye) are available in wheat as segments of alien chromosome translocated to wheat chromosomes. Each of these genes provides resistance to all races of wheat stem rust currently found in Australia. We have developed robust PCR markers for Sr24 and Sr26 (this study) and SrR and Sr31 (previously reported) that are applicable across a wide selection of Australian wheat germplasm. Wheat lines have recently become available in which the size of the alien segments containing Sr26, SrR and Sr31 has been reduced. Newly developed PCR-markers can be used to identify the presence of the shorter alien segment in all cases. Assuming that these genes have different gene-for-gene specificities and that the wheat industry will discourage the use of varieties carrying single genes only, the newly developed PCR markers will facilitate the incorporation of two or more of the genes Sr24, Sr26, SrR and Sr31 into wheat lines and have the potential to provide durable control to stem rust in Australia and elsewhere.
and
are zoonotic, tick-borne pathogens that can cause febrile illnesses with or without other symptoms in humans, but may cause subclinical infections in animals. There are only a few reports on the ...occurrence of these pathogens in cattle and water buffalo in Southeast Asia, including the Philippines. In this study, molecular detection of
and
in the blood and in the
(
)
ticks of cattle and water buffalo from five provinces in Luzon Island of the Philippines was done. A total of 620 blood samples of cattle and water buffalo and 206 tick samples were collected and subjected to DNA extraction. After successful amplification of control genes, nested PCR was performed to detect
of
and
of
. No samples were positive for
, while 10 (cattle = 7, water buffaloes = 3), or 1.6% of blood, and five, or 1.8% of tick samples, were
-positive. Sequence analysis of the positive amplicons showed 99-100% similarity to reported
isolates. This molecular evidence on the occurrence of
in Philippine ruminants and cattle ticks and its zoonotic nature should prompt further investigation and surveillance to facilitate its effective control.
The stem, leaf and stripe rust resistance genes Sr31, Lr26 and Yr9, located on the short arm of rye chromosome 1, have been widely used in wheat by means of wheat-rye translocation chromosomes. ...Previous studies have suggested that these resistance specificities are encoded by either closely-linked genes, or by a single gene capable of recognizing all three rust species. To investigate these issues, two 1BL.1RS wheat lines, one with and one without Sr31, Lr26 and Yr9, were used as parents for a high-resolution F2 mapping family. Thirty-six recombinants were identified between two PCR markers 2.3 cM apart that flanked the resistance locus. In one recombinant, Lr26 was separated from Sr31 and Yr9. Mutation studies recovered mutants that separated all three rust resistance genes. Thus, together, the recombination and mutation studies suggest that Sr31, Lr26 and Yr9 are separate closely-linked genes. An additional 16 DNA markers were mapped in this region. Multiple RFLP markers, identified using part of the barley Mla powdery mildew resistance gene as probe, co-segregated with Sr31 and Yr9. One deletion mutant that had lost Sr31, Lr26 and Yr9 retained all Mla markers, suggesting that the family of genes on 1RS identified by the Mla probe does not contain the Sr31, Lr26 or Yr9 genes. The genetic stocks and DNA markers generated from this study should facilitate the future cloning of Sr31, Lr26 and Yr9.
Tobacco smoking and obesity are leading causes of preventable morbidity and mortality in the US, and primary care physicians are the main source of preventive care. However, it is not known whether ...access for new patients is affected by an expression of interest in preventive care. In a 2015 audit, we called US primary care physicians' offices to request appointment information regarding new patient physicals for simulated patients. Simulated patients were differentiated by smoking concerns (N = 907), weight concerns (N = 867), or no health concerns (“healthy” patients; N = 3561). Additionally, patient profiles varied by race/ethnicity, sex, and insurance type. We also examined whether access differed in states that expanded Medicaid under the Affordable Care Act. We found that physicians' offices were no more likely to offer appointments to patients with smoking concerns than to healthy patients (54% vs. 55%; p-value = 0.56), and patients with smoking concerns were offered fewer appointments than patients with weight concerns (54% vs. 62%, p-value < 0.01). In analyses adjusted for covariates, smoking concerns did not improve appointment offers for any patient group, and reduced Medicare patients' offers in Medicaid expansion states by 9 percentage points relative to healthy patients (95% CI: −16, −2). Health concerns did not statistically significantly affect waits-to-appointment. Our results suggest that patients with smoking concerns are no more likely to be offered new patient appointments than those with no health concerns. The greater likelihood of appointment offers for some patients with weight concerns is encouraging for obesity prevention and management.
•Patients with smoking concerns are no more likely to be offered new patient appointments than the healthy.•Some patients with weight concerns have a modest advantage over healthy patients.•Patients with smoking concerns are offered fewer appointments than patients with weight concerns.•Health status did not affect waits-to-appointment for patients offered appointments.
Degenerate oligonucleotide primers were designed on the basis of nucleotide-binding-site (NBS) motifs conserved between resistance genes of Arabidopsis, flax and tobacco and subsequently used as PCR ...primers to amplify resistance gene analogues (RGA) in rice. Primers amplified a major band of approximately 500bp. Restriction analysis of the amplified product revealed that the band was made up of several different fragments. Many of these fragments were cloned. Sixty different cloned fragments were analysed and assigned to 14 categories based on Southern blot analysis. Fourteen clones, each representing one of the 14 categories of RGAs were mapped onto the rice genetic map using a Nipponbare (japonica)×'Kasalath' (indica) mapping population consisting of 186 F^sub 2^ lines. Of the 14 clones representing each class 12 could be mapped onto five different chromosomes of rice with a major cluster of 8 RGAs on chromosome 11. Our results indicate that it is possible to use sequence homology from conserved motifs of known resistance genes to amplify candidate resistance genes from diverse plant taxa.PUBLICATION ABSTRACT
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