Identification and characterization of the Non-race specific Disease Resistance 1 (NDR1) orthologous protein in coffee

<p>Abstract</p> <p>Background</p> <p>Leaf rust, which is caused by the fungus <it>Hemileia vastatrix </it>(Pucciniales), is a devastating disease that affects coffee plants (<it>Coffea arabica </it>L.). Disadvantages that are associated with currently developed phytoprotection approaches have recently led to the search for alternative strategies. These include genetic manipulations that constitutively activate disease resistance signaling pathways. However, molecular actors of such pathways still remain unknown in <it>C. arabica</it>. In this study, we have isolated and characterized the coffee <it>NDR1 </it>gene, whose <it>Arabidopsis </it>ortholog is a well-known master regulator of the hypersensitive response that is dependent on coiled-coil type R-proteins.</p> <p>Results</p> <p>Two highly homologous cDNAs coding for putative NDR1 proteins were identified and cloned from leaves of coffee plants. One of the candidate coding sequences was then expressed in the <it>Arabidopsis </it>knock-out null mutant <it>ndr1-1</it>. Upon a challenge with a specific strain of the bacterium <it>Pseudomonas syringae </it>(DC3000::<it>AvrRpt2</it>), analysis of both macroscopic symptoms and <it>in planta </it>microbial growth showed that the coffee cDNA was able to restore the resistance phenotype in the mutant genetic background. Thus, the cDNA was dubbed <it>CaNDR1a </it>(standing for <it>Coffea arabica Non-race specific Disease Resistance 1a</it>). Finally, biochemical and microscopy data were obtained that strongly suggest the mechanistic conservation of the <it>NDR1</it>-driven function within coffee and <it>Arabidopsis </it>plants. Using a transient expression system, it was indeed shown that the CaNDR1a protein, like its <it>Arabidopsis </it>counterpart, is localized to the plasma membrane, where it is possibly tethered by means of a GPI anchor.</p> <p>Conclusions</p> <p>Our data provide molecular and genetic evidence for the identification of a novel functional <it>NDR1 </it>homolog in plants. As a key regulator initiating hypersensitive signalling pathways, <it>CaNDR1 </it>gene(s) might be target(s) of choice for manipulating the coffee innate immune system and achieving broad spectrum resistance to pathogens. Given the potential conservation of <it>NDR1</it>-dependent defense mechanisms between <it>Arabidopsis </it>and coffee plants, our work also suggests new ways to isolate the as-yet-unidentified <it>R</it>-gene(s) responsible for resistance to <it>H. vastatrix</it>.</p

Coffee resistance to the main diseases : leaf rust and coffee berry disease

Sucesso considerável tem sido obtido no uso do melhoramento clássico para o controle de doenças de plantas economicamente importantes, tais como a ferrugem alaranjada das folhas e a antracnose dos frutos do cafeeiro (CBD). Há um grande consenso de que o uso de plantas geneticamente resistentes é o meio mais apropriado e eficaz em termos de custos do controle das doenças das plantas, sendo também um dos elementos chave do melhoramento da produção agrícola. Tem sido também reconhecido que um melhor conhecimento do agente patogênico e dos mecanismos de defesa das plantas permitirá o desenvolvimento de novas abordagens no sentido de aumentar a durabilidade da resistência. Após uma breve descrição de conceitos na área da resistência das plantas às doenças, nesta revisão tentou-se dar uma idéia do progresso na investigação da ferrugem alaranjada do cafeeiro e do CBD relativamente ao processo de infecção e variabilidade dos agentes patogênicos, melhoramento do cafeeiro para a resistência e mecanismos de resistência do cafeeiro

Identification and characterization of the Non- race specific Disease Resistance 1 (NDR1) orthologous protein in coffee

Abstract Background: Leaf rust, which is caused by the fungus Hemileia vastatrix (Pucciniales), is a devastating disease that affects coffee plants (Coffea arabica L.). Disadvantages that are associated with currently developed phytoprotection approaches have recently led to the search for alternative strategies. These include genetic manipulations that constitutively activate disease resistance signaling pathways. However, molecular actors of such pathways still remain unknown in C. arabica. In this study, we have isolated and characterized the coffee NDR1 gene, whose Arabidopsis ortholog is a well-known master regulator of the hypersensitive response that is dependent on coiledcoil type R-proteins

Микола Сушко та Організація українських націоналістів: до питання про партійно-політичну приналежність голови Української установи довіри в Німецькій імперії (1938–1945)

В публікації досліджується питання партійно-політичної приналежності голови Української установи довіри в Німецькій імперії д-ра Миколи Сушка (1938–1945).В публикации исследуется вопрос о партийно-политической принадлежности председателя Украинского учреждения доверия в Германии д-ра Николая Сушко (1938–1945).The publication contains a study on the problem of party-political membership of the Head of the Ukrainian Trust Institution in German Empire Dr. Mykola Sushko (1938–1945)

Glutaredoxin regulation of primary root growth is associated with early drought stress tolerance in pearl millet

Seedling root traits impact plant establishment under challenging environments. Pearl millet is one of the most heat and drought tolerant cereal crops that provides a vital food source across the sub-Saharan Sahel region. Pearl millet’s early root system features a single fast-growing primary root which we hypothesize is an adaptation to the Sahelian climate. Using crop modeling, we demonstrate that early drought stress is an important constraint in agrosystems in the Sahel where pearl millet was domesticated. Furthermore, we show that increased pearl millet primary root growth is correlated with increased early water stress tolerance in field conditions. Genetics including genome-wide association study and quantitative trait loci (QTL) approaches identify genomic regions controlling this key root trait. Combining gene expression data, re-sequencing and re-annotation of one of these genomic regions identified a glutaredoxin-encoding gene PgGRXC9 as the candidate stress resilience root growth regulator. Functional characterization of its closest Arabidopsis homolog AtROXY19 revealed a novel role for this glutaredoxin (GRX) gene clade in regulating cell elongation. In summary, our study suggests a conserved function for GRX genes in conferring root cell elongation and enhancing resilience of pearl millet to its Sahelian environment

Author Response: Glutaredoxin regulation of primary root growth is associated with early drought stress tolerance in pearl millet

Seedling root traits impact plant establishment under challenging environments. Pearl millet is one of the most heat and drought tolerant cereal crops that provides a vital food source across the sub-Saharan Sahel region. Pearl millet’s early root system features a single fast-growing primary root which we hypothesize is an adaptation to the Sahelian climate. Using crop modelling, we demonstrate that early drought stress is an important constraint in agrosystems in the Sahel where pearl millet was domesticated. Furthermore, we show that increased pearl millet primary root growth is correlated with increased early water stress tolerance in field conditions. Genetics including GWAS and QTL approaches identify genomic regions controlling this key root trait. Combining gene expression data, re-sequencing and re-annotation of one of these genomic regions identified a glutaredoxin-encoding gene PgGRXC9 as the candidate stress resilience root growth regulator. Functional characterization of its closest Arabidopsis homolog AtROXY19 revealed a novel role for this glutaredoxin (GRX) gene clade in regulating cell elongation. In summary, our study suggests a conserved function for GRX genes in conferring root cell elongation and enhancing resilience of pearl millet to its Sahelian environment

Contacts et acculturations en Méditerranée occidentale

La question des contacts entre les différents peuples qui bordent les rives de la Méditerranée nord occidentale est l’un des sujets phares de la recherche archéologique de ces trente dernières années. Que l’on parle d’époque archaïque et classique ou de Protohistoire et d’âge du Fer, les échanges et les processus d’acculturation de ces peuples qui entrèrent alors en contact les uns avec les autres : Grecs, Celtes, Phéniciens, Ibères, Ligures, Étrusques, ont retenu l’attention des chercheurs travaillant sur l’expansion grecque dans ces régions, sur les trafics commerciaux, sur les échanges culturels. L’œuvre de Michel Bats (Directeur de recherche honoraire du CNRS) traverse toutes ces thématiques : la présence des Phocéens et des Étrusques dans le bassin occidental de la Méditerranée, l’acculturation et les identités ethno-culturelles, les recherches sur la céramique et ses usages dans une perspective anthropologique, l’appropriation de l’écriture par les sociétés protohistoriques. Ses collègues et amis, en organisant ce colloque et en participant à ces actes, entendent lui témoigner leur amitié et leur dette intellectuelle. Ce volume réunit des articles des meilleurs spécialistes, actuels de la question - des chercheurs de toute la Méditerranée - autour des quatre grands thèmes que nous venons d’évoquer afin tout à la fois de dresser un bilan et de définir de nouvelles perspectives. Cet ouvrage présente donc aussi bien des synthèses - sur la présence grecque en Espagne, sur l’origine de l’écriture, sur les pratiques funéraires, sur les identités culturelles et ethniques - que des découvertes récentes concernant la thématique des contacts et de l’acculturation en Méditerranée nord occidentale : l’agglomération du Premier âge du Fer de La Cougourlude (Lattes, Hérault) fouillée durant l’été 2010 ; le sanctuaire hellénistique de Cumes et les fouilles récentes de Fratte en Italie ; les ateliers de potiers de Rosas en Espagne ; les dernières découvertes d’Olbia de Provence

Sub-genomic origin and regulation patterns of a duplicated WRKY gene in the allotetraploid species #Coffea arabica$

International audienceThe extensively cultivated coffee species Coffea arabica is an allotetraploid resulting from a recent hybridization between two wild diploid Coffea species. We describe in this paper the first identification and functional assessment of homoeologous gene copies in C. arabica. When cloning the CaWRKY1 gene encoding a transcription factor of the WRKY superfamily associated with plant defense responses to pathogens (Ganesh et al. in Plant Sci 170:1045-1051, 2006), two distinct gene copies (CaWRKY1a and CaWRKY1b) were obtained from C. arabica. Southern blots experiments and phylogenetic analysis of the WRKY1 gene in related diploid Coffea species showed that CaWRKY1a and CaWRKY1b are homoeologous sequences in the allopolyploid coffee genome and are probably close descents of the extant Coffea canephora and C. eugenioides WRKY1 genes. To verify if CaWRKY1a and CaWRKY1b were both functional, gene expressions were monitored in C. arabica plants challenged by the rust fungus Hemileia vastatrix, the root-knot nematode Meloidogyne exigua, and after several abiotic treatments. Real-time quantitative polymerase chain reaction (PCR) assays showed that CaWRKY1 homoeologs were concomitantly expressed and displayed the same altered patterns of expression in leaves and roots during biotic and abiotic treatments. These results suggest that CaWRKY1a and CaWRKY1b were functionally retained in the coffee genome after allopolyploidization and that no functional divergence occurred between the duplicated genes in the C. arabica genome. This study provides the first molecular data on sub-genome-specific expression in allopolyploid coffee. The origin of the C. arabica sub-genomes is discussed with regards on the probable progenitors of this important crop species