Gene-specific markers for the wheat gene Lr34/Yr18/Pm38 which confers resistance to multiple fungal pathogens

The locus Lr34/Yr18/Pm38 confers partial and durable resistance against the devastating fungal pathogens leaf rust, stripe rust, and powdery mildew. In previous studies, this broad-spectrum resistance was shown to be controlled by a single gene which encodes a putative ATP-binding cassette transporter. Alleles of resistant and susceptible cultivars differed by only three sequence polymorphisms and the same resistance haplotype was found in the three independent breeding lineages of Lr34/Yr18/Pm38. Hence, we used these conserved sequence polymorphisms as templates to develop diagnostic molecular markers that will assist selection for durable multi-pathogen resistance in breeding programs. Five allele-specific markers (cssfr1-cssfr5) were developed based on a 3bp deletion in exon 11 of the Lr34-gene, and one marker (cssfr6) was derived from a single nucleotide polymorphism in exon 12. Validation of reference genotypes, well characterized for the presence or absence of the Lr34/Yr18/Pm38 resistance locus, demonstrated perfect diagnostic values for the newly developed markers. By testing the new markers on a larger set of wheat cultivars, a third Lr34 haplotype, not described so far, was discovered in some European winter wheat and spelt material. Some cultivars with uncertain Lr34 status were re-assessed using the newly derived markers. Unambiguous identification of the Lr34 gene aided by the new markers has revealed that some wheat cultivars incorrectly postulated as having Lr34 may possess as yet uncharacterised loci for adult plant leaf and stripe rust resistanc

Abscisic acid is a substrate of the ABC transporter encoded by the durable wheat disease resistance gene Lr34

The wheat Lr34res allele, coding for an ATP-binding cassette transporter, confers durable resistance against multiple fungal pathogens. The Lr34sus allele, differing from Lr34res by two critical nucleotide polymorphisms, is found in susceptible wheat cultivars. Lr34res is functionally transferrable as a transgene into all major cereals, including rice, barley, maize, and sorghum. Here, we used transcriptomics, physiology, genetics, and in vitro and in vivo transport assays to study the molecular function of Lr34. We report that Lr34res results in a constitutive induction of transcripts reminiscent of an abscisic acid (ABA)-regulated response in transgenic rice. Lr34-expressing rice was altered in biological processes that are controlled by this phytohormone, including dehydration tolerance, transpiration and seedling growth. In planta seedling and in vitro yeast accumulation assays revealed that both LR34res and LR34sus act as ABA transporters. However, whereas the LR34res protein was detected in planta the LR34sus version was not, suggesting a post-transcriptional regulatory mechanism. Our results identify ABA as a substrate of the LR34 ABC transporter. We conclude that LR34res-mediated ABA redistribution has a major effect on the transcriptional response and physiology of Lr34res-expressing plants and that ABA is a candidate molecule that contributes to Lr34res-mediated disease resistance

Neue Technologien in der Pflanzenforschung – eine Alternative zu Pflanzenschutzmitteln?: Tagungsband zur Fachtagung Dialog Grün

Bietet die moderne Pflanzenforschung Alternativen zum Einsatz von Pflanzenschutzmitteln? Dies war die Kernfrage der Fachtagung Dialog Grün, die am 8. Juni 2016 an der ETH Zürich stattgefunden hat. Anwesend waren 120 Vertreter von Wissenschaft, Wirtschaft, Bundesämtern und kantonaler Verwaltung, NGOs und Konsumentenschutzorganisationen, sowie des Schweizer Bauernverbands. Präsentiert wurden neue Technologien wie der RNA Interferenz, Genome Editing (CRISPR/Cas), Nanotechnologie und Microbiomics. Ihr Nutzen für die Landwirtschaft, insbesondere den Pflanzenschutz, wurde von allen Referenten klar und deutlich dargelegt. Frau Dr. Eva Reinhard, (stv. Direktorin Bundesamt für Landwirtschaft BLW) betonte den Bedarf für neue Technologien für eine nachhaltige und wettbewerbsfähige Schweizer Landwirtschaft. Sie wies aber darauf hin, dass eine Integration in systemische Ansätze erfolgen muss, um die Wertschöpfung für Schweizer Produzenten und Konsumenten zu gewährleisten. Prof. Georg Simonis und Prof. Armin Grunwald betonten in ihren Referaten, dass ein frühzeitiger Dialog zwischen Regierungen, Bürgern und Wissenschaftlern notwendig ist. Akzeptanz für neue Technologien kann nur durch Vertrauen aufgebaut werden. Nur wo Technologien bereits in einem sehr frühen Stadium gemeinsam diskutiert werden und wo die gesellschaftliche Einbettung gemeinsam gestaltet wird, kann Akzeptanz entstehen. Zwei anschauliche Beispiele zeigten auf, das Methoden der partizipative Technikfolgenabschätzung den erwünschten Risiko-und Nutzendialog voran treiben könnten. Die praktische Umsetzung allerdings lässt noch viele Fragen offen. Formate und Rahmenbedinungen für partizipative TA müssen erst geschaffen werden, konkrete Forschungsfragen gemeinsam formuliert werden. Die Akzeptanz oder Ablehnung neuer technologischer Entwicklungen ist neben der individuellen Kosten-/Nutzenanalyse auch an Werte und Weltanschauungen gebunden ist. Letztendlich steht nicht die Technik (in Bezug auf die Transfermethoden) in der Kritik, sondern die neuen Technologien werden in ihrer Instrumentalisierung zur Durchsetzung einer bestimmten Landwirtschaft kritisiert. Die Art und Weise wie neuen Technologien bewertet werden, kann nicht ohne den sozialen Kontext, in den sie eingebettet sind, verstanden werden. Jede soziale Gruppe hat ein anderes Verständnis zur Bedeutung der Technologie. Unterschiedliche Interessen und Wertevorstellung prallen aufeinander

The Swiss approach to precision medicine

Precision or personalised medicine/health aims to prevent, diagnose and treat diseases by taking into account individual variability of genes, environment and lifestyle for each person. In order to tap the full potential of the increasing amount of molecular, biological and clinical health data, new infrastructures are required that permit collection, storage and analysis of high quality data and adequately link biobank samples to clinical data. Many countries have started to build interconnected “precision/personalised medicine ecosystems”, but the federalist and heterogeneous healthcare system has so far prevented nationwide coordinated activities in Switzerland. Therefore, the Swiss Personalized Health Network (SPHN) initiative has been launched. Its mission is to lay the foundations for personalised health on a national level by the development of a nationally coordinated interoperable data infrastructure to enable nationwide accessibility and exchange of health-related data. This paper describes the goals of SPHN, its current procedures and funding regulations, its organisation, its ethical and legal framework for responsible data processing, its data management infrastructure and information security and its relevant partnerships with other organisations and institutions. Although the SPHN initiative starts with the institutions of higher education such as university hospitals, universities and the ETH domain, other hospitals, public health institutions and medical practitioners, as well as private institutions such as industry and health insurers, will be included into the initiative at a later time point. Ultimately, the SPHN initiative shall lead to the development of an effective Swiss personalised health ecosystem, which is required to advance effective individual prevention, diagnosis and treatment of disease states and to push Switzerland to the international forefront of personalised health-related research and health care.ISSN:1424-7860ISSN:1424-399

Functional variability of the Lr34 durable resistance gene in transgenic wheat

Breeding for durable disease resistance is challenging, yet essential to improve crops for sustainable agriculture. The wheat Lr34 gene is one of the few cloned, durable resistance genes in plants. It encodes an ATP binding cassette transporter and has been a source of resistance against biotrophic pathogens, such as leaf rust (Puccinina triticina), for over 100 years. As endogenous Lr34 confers quantitative resistance, we wanted to determine the effects of transgenic Lr34 with specific reference to how expression levels affect resistance. Transgenic Lr34 wheat lines were made in two different, susceptible genetic backgrounds. We found that the introduction of the Lr34 resistance allele was sufficient to provide comparable levels of leaf rust resistance as the endogenous Lr34 gene. As with the endogenous gene, we observed resistance in seedlings after cold treatment and in flag leaves of adult plants, as well as Lr34-associated leaf tip necrosis. The transgene-based Lr34 resistance did not involve a hypersensitive response, altered callose deposition or up-regulation of PR genes. Higher expression levels compared to endogenous Lr34 were observed in the transgenic lines both at seedling as well as adult stage and some improvement of resistance was seen in the flag leaf. Interestingly, in one genetic background the transgenic Lr34-based resistance resulted in improved seedling resistance without cold treatment. These data indicate that functional variability in Lr34-based resistance can be created using a transgenic approach

The wheat durable, multipathogen resistance gene Lr34 confers partial blast resistance in rice

The wheat gene Lr34 confers durable and partial field resistance against the obligate biotrophic, pathogenic rust fungi and powdery mildew in adult wheat plants. The resistant Lr34 allele evolved after wheat domestication through two gain-of-function mutations in an ATP-binding cassette transporter gene. An Lr34-like fungal disease resistance with a similar broad-spectrum specificity and durability has not been described in other cereals. Here, we transformed the resistant Lr34 allele into the japonica rice cultivar Nipponbare. Transgenic rice plants expressing Lr34 showed increased resistance against multiple isolates of the hemibiotrophic pathogen Magnaporthe oryzae, the causal agent of rice blast disease. Host cell invasion during the biotrophic growth phase of rice blast was delayed in Lr34-expressing rice plants, resulting in smaller necrotic lesions on leaves. Lines with Lr34 also developed a typical, senescence-based leaf tip necrosis (LTN) phenotype. Development of LTN during early seedling growth had a negative impact on formation of axillary shoots and spikelets in some transgenic lines. One transgenic line developed LTN only at adult plant stage which was correlated with lower Lr34 expression levels at seedling stage. This line showed normal tiller formation and more importantly, disease resistance in this particular line was not compromised. Interestingly, Lr34 in rice is effective against a hemibiotrophic pathogen with a lifestyle and infection strategy that is different from obligate biotrophic rusts and mildew fungi. Lr34 might therefore be used as a source in rice breeding to improve broad-spectrum disease resistance against the most devastating fungal disease of rice. (Résumé d'auteur

The wheat resistance gene Lr34 results in the constitutive induction of multiple defense pathways in transgenic barley

The wheat gene Lr34 encodes an ABCG-type transporter which provides durable resistance against multiple pathogens. Lr34 is functional as a transgene in barley, but its mode of action has remained largely unknown both in wheat and barley. Here we studied gene expression in uninfected barley lines transgenic for Lr34. Genes from multiple defense pathways contributing to basal and inducible disease resistance were constitutively active in seedlings and mature leaves. In addition, the hormones jasmonic acid and salicylic acid were induced to high levels, and increased levels of lignin as well as hordatines were observed. These results demonstrate a strong, constitutive re-programming of metabolism by Lr34. The resistant Lr34 allele (Lr34res) encodes a protein that differs by two amino acid polymorphisms from the susceptible Lr34sus allele. The deletion of a single phenylalanine residue in Lr34sus was sufficient to induce the characteristic Lr34-based responses. Combination of Lr34res and Lr34sus in the same plant resulted in a reduction of Lr34res expression by 8- to 20-fold when the low-expressing Lr34res line BG8 was used as a parent. Crosses with the high-expressing Lr34res line BG9 resulted in an increase of Lr34sus expression by 13- to 16-fold in progenies that inherited both alleles. These results indicate an interaction of the two Lr34 alleles on the transcriptional level. Reduction of Lr34res expression in BG8 crosses reduced the negative pleiotropic effects of Lr34res on barley growth and vigor without compromising disease resistance, suggesting that transgenic combination of Lr34res and Lr34sus can result in agronomically useful resistance