Search

Since emerging in Brazil in 1985, wheat blast has spread throughout South America and recently appeared in Bangladesh and Zambia. Here we show that two wheat resistance genes, Rwt3 and Rwt4, acting as host-specificity barriers against non-Triticum blast pathotypes encode a nucleotide-binding leucine-rich repeat immune receptor and a tandem kinase, respectively. Molecular isolation of these genes will enable study of the molecular interaction between pathogen effector and host resistance genes.

Feeding the world's ever‐increasing population requires continuous development of high‐yielding and disease‐resistant cultivars of food crops such as wheat (Triticum aestivum L.). Speed breeding, which utilizes longer photoperiod times and higher temperatures, is a technique that accelerates plant development and is rapidly being adopted by wheat breeders across the globe to fast‐track cultivar development. Plant diseases are a major threat to crop production, and breeding for disease resistance is a major goal of crop breeders. Fusarium head blight (FHB), caused by Fusarium graminearum, is a major disease of small grain cereals, affecting their yield and quality. The aim of present work was to assess if speed breeding conditions can be used to accelerate reliable assessment of FHB severity and mycotoxin deoxynivalenol (DON) accumulation in wheat varieties. We screened a set of six spring wheat genotypes with different levels of genetic resistance (two moderately susceptible, two highly susceptible, one moderately resistant, and one resistant) for their response to FHB at 14 days after inoculation (dai) and 21 dai and DON accumulation under normal versus speed breeding conditions. FHB severity and DON accumulation were found to be highly correlated at all time points under normal and speed breeding conditions. Robust differentiation between resistant and susceptible genotypes could be achieved at 14 dai rather than the normal period of 21 dai, saving at least a week in phenotyping. Combined with the accelerated growth, flowering, and maturity under these conditions, efficient FHB screening and DON evaluation under speed breeding conditions will fast‐track development of resistant wheat varieties. Core Ideas: Speed breeding is increasingly being adopted by crop breeding programs.We evaluated spring wheat genotypes with different levels of genetic resistance for Fusarium head blight (FHB) and deoxynivalenol (DON) levels under speed breeding versus regular conditions.Reliable distinction could be made in FHB severity at 14 days after inoculation (dai) under speed breeding as compared to 21 dai under normal growth conditions.Growing and testing the plants under speed breeding conditions saved a total of 21–23 days as compared to regular conditions. [ABSTRACT FROM AUTHOR]

Aegilops tauschii (2n = 2x = 14, genome DD), also known as Tausch's goatgrass, is the D genome donor of bread or hexaploid wheat Triticum aestivum (2n = 2x = 42, AABBDD genome). It is a rich reservoir of useful genes for biotic and abiotic stress tolerance for wheat improvement. We developed a TILLING (Targeting Induced Local Lesions In Genomes) resource for Ae. tauschii for discovery and validation of useful genes in the D genome of wheat. The population, referred to as TILL-D, was developed with ethyl methanesulfonate (EMS) mutagen. The survival rate in M1 generation was 73%, out of which 22% plants were sterile. In the M2 generation 25% of the planted seeds showed phenotypic mutations such as albinos, chlorinas, no germination, variegated, sterile and partially fertile events, and 2,656 produced fertile M2 plants. The waxy gene was used to calculate the mutation frequency (1/70 kb) of the developed population, which was found to be higher than known mutation frequencies for diploid plants (1/89–1/1000 kb), but lower than that for a polyploid species (1/24–1/51 kb). The TILL-D resource, together with the newly published Ae. tauschii reference genome sequence, will facilitate gene discoveries and validations of agronomically important traits and their eventual fine transfer in bread wheat. [ABSTRACT FROM AUTHOR]

In this article, the author discusses several court cases regarding the clarification for patent eligibility. The author mentions that the machine-or-transformation test by the Federal Circuit cannot be considered as an exclusive test regarding patent eligibility. Furthermore, the author states that the claims may still be eligible if they do not fall on the prohibited categories even if they fail to pass on the machine-or-transformation test.

Aim Whenever homozygous alleles are encountered by sequence-based typing (SBT), it is our protocol to confirm by another typing method that allele dropouts have not occurred. We present a case where DNA extracted from peripheral blood was homozygous for an HLA-A locus when tested by SBT. This assignment was confirmed by SSP. However, follow-up testing with buccal swab extracted DNA resulted in the detection of an additional HLA-A allele. Methods A patient with T-cell large granular lymphocyte leukemia (TLGL) was initially typed by SBT (Life Technologies SeCore) for HLA-A, B, C, DRB1, DQB1, and DPB1 using DNA extracted from peripheral blood. We subsequently typed six siblings as potential donors by SBT for A, B, and DRB1 loci using buccal swab extractions. Results The typing assignments of sibling donors led us to further investigate the typing of the patient when trying to establish family haplotypes. The recipient was typed as A ∗ 02:05 homozygous, which was confirmed by SSP (Invitrogen). However, the family study suggested that A ∗ 68:01 had dropped out of the recipient. We noticed very low peaks at the positions that assigned A ∗ 68:01 in the SBT software. We ordered a buccal swab on this patient in order to clarify the family study. (Interestingly, this patient’s diagnosis is linked to deletions in chromosome 6.) The buccal swab extracted DNA revealed A ∗ 68:01 in SBT typing, demonstrating that the A ∗ 68:01 had indeed dropped out in the peripheral blood. Conclusion Using buccal swab- extracted DNA is recommended when confirming homozygous assignment and allele dropouts for stem cell transplant candidates who are originally typed by peripheral blood extracted DNA. [ABSTRACT FROM AUTHOR]

Aim: We wanted to see how accurately we can predict HLA-DQA1 assignments by using NMDP published DRB1/DQB1/DQA1 associations. Methods: We selected a total of 116 samples that were previously typed. Seventy two of these samples were proficiency testing samples and the remaining forty four were clinical samples typed in our Laboratory using Life Technologies DQA1-SSP kits. Using the NMDP association chart, we assigned DQA1 alleles for all the samples based on the DRB1/DQB1 association. We then compared our assignments with the actual typing. Results: By counting homozygous alleles as one, a total of two hundred seventeen alleles were defined. Nine of these DRB1/DQB1/DQA1 associations were not listed on the NMDP chart possibly due to uncommon DRB1/DQB1 associations. Out of the nine, eight could be assigned correctly based on the published association with DRB1 allele group. The remaining one sample could not be assigned correctly. Of the two hundred eight remaining allele assignments two hundred six agreed at least at the allele group level. Conclusions: Our data demonstrates that DQA1 assignment can be inferred on the basis of DRB1/DQB1 association at least at an allele group level with an accuracy rate of 99%. While this may not be a justifiable approach to stem cell transplantation, it certainly has application in solid organ transplantation. [Copyright &y& Elsevier]

Aim: The purpose of this study was to correlate the presence of anti- DQA1 antibodies with crossmatch outcome. Methods: Over a period of nine months, we identified eleven patient samples which contained anti-DQA1 antibodies. Samples were selected having MFI values greater than 4000 using Class II single antigen bead analysis. The DQA1 specificities assigned were: DQA1∗01,02,03,04,05,06. Each one of these samples was tested in three color flow cytometry crossmatches with several donor cells that were positive for the assigned DQA1 specificities as well as with cells that lacked the desired antigen. Results: Suprisingly, only two of the eleven samples yielded the predicted result: one was positive when the specific allele group antigen was present, and the other sample (multiple specificity assignments) was negative when selectively crossmatched with cells that lacked the assigned DQA1 antigens. The remaining nine sera did not correlate with the expected crossmatch outcome. Conclusions: Our data demonstrates that we cannot accurately predict crossmatch outcomes mediated by Anti- DQA1 antibodies that were characterized by Class II single antigen beads. This could have serious impacts whenever virtual crossmatching involves Anti-DQA1 antibodies. If assiged anti-DQA1 antibodies can not correlate with a crossmatch outcome, we conclude that typing for DQA1 will not be particularly helpful in identifying a crossmatch-suitable donor. [Copyright &y& Elsevier]

Fusarium head blight (FHB) primarily caused by Fusarium graminearum is a key disease of small grains. Diseased spikes show symptoms of premature bleaching shortly after infection and have aborted or shriveled seeds, resulting in reduced yields. The fungus also deteriorates quality and safety of the grain because of production of mycotoxins, especially deoxynivalenol (DON), which can result in grain being docked or rejected at the point of sale. Genetic host resistance to FHB is quantitative, and no complete genetic resistance against this devastating disease is available. Alternative approaches to develop new sources of FHB resistance are needed. In this study, we performed extensive forward genetic screening of the M 4 generation of an ethyl methane sulfonate-induced mutagenized population of cultivar Jagger to isolate variants with FHB resistance. In field testing, 74 mutant lines were found to have resistance against FHB spread, and 30 of these lines also had low DON content. Subsequent testing over 2 years in controlled greenhouse conditions revealed 10 M 6 lines showing significantly lower FHB spread. Seven and 6 of those 10 lines also had reduced DON content and fewer Fusarium -damaged kernels, respectively. Future endeavors will include identification of the mutations that led to resistance in these variants.

Targeting Induced Local Lesions IN Genomes (TILLING) is a powerful reverse genetics tool that includes chemical mutagenesis and detection of sequence variation in target genes. TILLING is a highly valuable functional genomics tool for gene validation, especially in small grains in which transformation-based approaches hold serious limitations. Developing a robust mutagenized population is key to determining the efficiency of a TILLING-based gene validation study. A TILLING population with a low overall mutation frequency indicates that an impractically large population must be screened to find desired mutations, whereas a high mutagen concentration leads to high mortality in the population, leading to an insufficient number of mutagenized individuals. Once an effective population is developed, there are multiple ways to detect mutations in a gene of interest, and the choice of platform depends upon the experimental scale and availability of resources. The Cel-1 assay and agarose gel-based approach for mutant identification is convenient, reproducible, and a less resource-intensive platform. It is advantageous in that it is simple, requiring no computational knowledge, and it is especially suitable for validation of a small number of genes with basic lab equipment. In the present article, described are the methods for development of a good TILLING population, including preparation of the dosage curve, mutagenesis and maintenance of the mutant population, and screening of the mutant population using the PCR-based Cel-1 assay.