1,720,985 research outputs found
Regulation and Evolution of NLR Genes: A Close Interconnection for Plant Immunity
No full textNLR (NOD-like receptor) genes belong to one of the largest gene families in plants.
Their role in plants’ resistance to pathogens has been clearly described for many members of this
gene family, and dysregulation or overexpression of some of these genes has been shown to induce
an autoimmunity state that strongly affects plant growth and yield. For this reason, these genes
have to be tightly regulated in their expression and activity, and several regulatory mechanisms are
described here that tune their gene expression and protein levels. This gene family is subjected to
rapid evolution, and to maintain diversity at NLRs, a plethora of genetic mechanisms have been
identified as sources of variation. Interestingly, regulation of gene expression and evolution of this
gene family are two strictly interconnected aspects. Indeed, some examples have been reported in
which mechanisms of gene expression regulation have roles in promotion of the evolution of this
gene family. Moreover, co-evolution of the NLR gene family and other gene families devoted to their
control has been recently demonstrated, as in the case of miRNAs
Parallel pigment and transcriptomic analysis of four barley albina and xantha mutants reveals the complex network of the chloroplast-dependent metabolism
No full textWe investigated the pigment composition and the transcriptome of albina (alb-e ( 16 ) and alb-f ( 17 )) and xantha (xan-s ( 46 ) and xan-b ( 12 )) barley mutants to provide an overall transcriptional picture of genes whose expression is interconnected with chloroplast activities and to search for candidate genes associated with the mutations. Beside those encoding plastid-localized proteins, more than 3,000 genes involved in non-chloroplast localized metabolism were up-/down-regulated in the mutants revealing the network of chloroplast-dependent metabolic pathways. The alb-e ( 16 ) mutant was characterized by overaccumulation of protoporphyrin IX upon ALA (5-amino levulinic acid) feeding and down-regulation of the gene encoding one subunit of Mg-chelatase, suggesting a block of the chlorophyll biosynthetic pathway before Mg-protoporphyrin IX biosynthesis, while alb-f ( 17 ) overaccumulated Mg-protoporphyrin IX and repressed PorA expression, without alterations in Mg-chelatase mRNA level. The alb-f ( 17 )mutant also showed overexpression of several genes involved in phytochrome and in phytochrome-dependent pathways. The results indicate that the down-regulation of Lhcb genes in alb-e ( 16 ) cannot be mediated by the accumulation of Mg-protoporphyrin IX. After ALA treatment, xan-s ( 46 ) showed overaccumulation of Mg-protoporphyrin IX, while the relative porphyrin composition of xan-b ( 12 ) was similar to wild type. The transcripts encoding the components of several mitochondrial metabolic pathways were up-regulated in albina/xantha leaves to compensate for the absence of active chloroplasts. The mRNAs encoding gun3, gun4, and gun5 barley homologous genes showed significant expression variations and were used to search for co-expressed genes across all samples. These analyses provide additional evidences on a chloroplast-dependent covariation of large sets of nuclear genes
Transcription analysis of cold acclimation in barley albina and xantha mutants reveals the key role of the chloroplast during plant adaptation to low temperature.
No full textPreviously, we have shown that barley (Hordeum vulgare) plants carrying a mutation preventing chloroplast development are completely frost susceptible as well as impaired in the expression of several cold-regulated genes. Here we investigated the transcriptome of barley albina and xantha mutants and the corresponding wild type to assess the effect of the chloroplast on expression of cold-regulated genes. First, by comparing control wild type against cold-hardened wild-type plants 2,735 probe sets with statistically significant changes (P = 0.05; ≥2-fold change) were identified. Expression of these wild-type cold-regulated genes was then analyzed in control and cold-hardened mutants. Only about 11% of the genes cold regulated in wild type were regulated to a similar extent in all genotypes (chloroplast-independent cold-regulated genes); this class includes many genes known to be under C-repeat binding factor control. C-repeat binding factor genes were also equally induced in mutants and wild-type plants. About 67% of wild-type cold-regulated genes were not regulated by cold in any mutant (chloroplast-dependent cold-regulated genes). We found that the lack of cold regulation in the mutants is due to the presence of signaling pathway(s) normally cold activated in wild type but constitutively active in the mutants, as well as to the disruption of low-temperature signaling pathway(s) due to the absence of active chloroplasts. We also found that photooxidative stress signaling pathway is constitutively active in the mutants. These results demonstrate the major role of the chloroplast in the control of the molecular adaptation to cold
The Interaction between Cold and Light Controls the Expression of the Cold-Regulated Barley Gene cor14b and the Accumulation of the Corresponding Protein
No full textValidation of a chlorophyll fluorescence-based method for selection for winterhardiness in cereals.
No full text29th International Horticultural Congress on Horticulture: Sustaining Lives, Livelihoods and Landscapes (IHC 2014): International Symposium on Molecular Biology in Horticulture
No full textBarley polyamine oxidase isoforms 1 and 2, a peculiar case of gene duplication. FEBS J. 2006 Sep;273(17):3990-4002. Epub 2006 Jul 19
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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