Project description:A wide range of environmental stresses lead to an elevated production of reactive oxygen species (ROS) in plant cells thus resulting in oxidative stress. The biological nitrogen fixation in the legume - Rhizobium symbiosis is at high risk of damage from oxidative stress. Common bean (Phaseolus vulgaris) active nodules exposed to the herbicide Paraquat (1,1 '-Dimethyl-4, 4'-bipyridinium dichloride hydrate) that generates ROS accumulation, showed a reduced nitrogenase activity and ureide content. We analyzed the global gene response of stressed nodules using the Bean CombiMatrix Custom Array 90K, that includes probes from some 30,000 expressed sequence tags (EST). A total of 4,280 ESTs were differentially expressed in oxidative stressed bean nodules; of these 2,218 were repressed. These genes were grouped in 44 different biological processes as defined by Gene Onthology. Analysis with the PathExpress bioinformatic tool, adapted for bean, identified five significantly repressed metabolic path
Project description:A wide range of environmental stresses lead to an elevated production of reactive oxygen species (ROS) in plant cells thus resulting in oxidative stress. The biological nitrogen fixation in the legume - Rhizobium symbiosis is at high risk of damage from oxidative stress. Common bean (Phaseolus vulgaris) active nodules exposed to the herbicide Paraquat (1,1 '-Dimethyl-4, 4'-bipyridinium dichloride hydrate) that generates ROS accumulation, showed a reduced nitrogenase activity and ureide content. We analyzed the global gene response of stressed nodules using the Bean CombiMatrix Custom Array 90K, that includes probes from some 30,000 expressed sequence tags (EST). A total of 4,280 ESTs were differentially expressed in oxidative stressed bean nodules; of these 2,218 were repressed. These genes were grouped in 44 different biological processes as defined by Gene Onthology. Analysis with the PathExpress bioinformatic tool, adapted for bean, identified five significantly repressed metabolic path This work presents the transcriptional profile of bean nodules, induced by strain Rhizobium tropici CIAT 899, under oxidative stress, generated experimentally by adding the herbicide Paraquat (1,1 '-Dimethyl-4, 4'-bipyridinium dichloride hydrate) for 48 hours. We analyzed the transcript profile, via microarray hybridization, using the Bean CombiMatrix Custom Array 90K, that includes probes from some 30,000 expressed sequence tags (EST). A total of 4,280 ESTs were differentially expressed in oxidative stressed bean nodules; of these 2,218 were repressed.
Project description:Common bean (Phaseolus vulgaris) and soybean (Glycine max) both belong to the Phaseoleae tribe and share significant coding sequence homology. To evaluate the utility of the soybean GeneChip for transcript profiling of common bean, we hybridized cRNAs purified from nodule, leaf, and root of common bean and soybean in triplicate to the soybean GeneChip. Initial data analysis showed a decreased sensitivity and specificity in common bean cross-species hybridization (CSH) GeneChip data compared to that of soybean. We employed a method that masked putative probes targeting inter-species variable (ISV) regions between common bean and soybean. A masking signal intensity threshold was selected that optimized both sensitivity and specificity. After masking for ISV regions, the number of differentially-expressed genes identified in common bean was increased by about 2.8-fold reflecting increased sensitivity. Quantitative RT-PCR analysis of a total of 20 randomly selected genes and purine-ureides pathway genes demonstrated an increased specificity after masking for ISV regions. We also evaluated masked probe frequency per probe set to gain insight into the sequence divergence pattern between common bean and soybean. The results from this study suggested that transcript profiling in common bean can be done using the soybean GeneChip. However, a significant decrease in sensitivity and specificity can be expected. Problems associated with CSH GeneChip data can be mitigated by masking probes targeting ISV regions. In addition to transcript profiling CSH of the GeneChip in combination with masking probes in the ISV regions can be used for comparative ecological and/or evolutionary genomics studies.
Project description:Common bean (Phaseolus vulgaris) and soybean (Glycine max) both belong to the Phaseoleae tribe and share significant coding sequence homology. To evaluate the utility of the soybean GeneChip for transcript profiling of common bean, we hybridized cRNAs purified from nodule, leaf, and root of common bean and soybean in triplicate to the soybean GeneChip. Initial data analysis showed a decreased sensitivity and specificity in common bean cross-species hybridization (CSH) GeneChip data compared to that of soybean. We employed a method that masked putative probes targeting inter-species variable (ISV) regions between common bean and soybean. A masking signal intensity threshold was selected that optimized both sensitivity and specificity. After masking for ISV regions, the number of differentially-expressed genes identified in common bean was increased by about 2.8-fold reflecting increased sensitivity. Quantitative RT-PCR analysis of a total of 20 randomly selected genes and purine-ureides pathway genes demonstrated an increased specificity after masking for ISV regions. We also evaluated masked probe frequency per probe set to gain insight into the sequence divergence pattern between common bean and soybean. The results from this study suggested that transcript profiling in common bean can be done using the soybean GeneChip. However, a significant decrease in sensitivity and specificity can be expected. Problems associated with CSH GeneChip data can be mitigated by masking probes targeting ISV regions. In addition to transcript profiling CSH of the GeneChip in combination with masking probes in the ISV regions can be used for comparative ecological and/or evolutionary genomics studies. We hybridized cRNA purified from nodule, leaf, and root of common bean and soybean in, triplicate, to the soybean GeneChip (18 GeneChip hybridizations = 2 species x 3 organs x 3 replicates).
Project description:P. syringae pv. phaseolicola is the causal agent of the halo blight disease of beans (Phaseolus vulgaris L). The disease attacks both foliage and pods of plant host. Many genes involve in pathogenicity and virulence are induced only in plant or in the presence of host components. In this work we investigated the effect of bean pod extract on the transcriptomic profile of the bacterium, when grown at low temperature in minimal medium with or without bean pod extract.
Project description:Background: Common bacterial blight (CBB) caused by Xanthomonas phaseoli pv. phaseoli and Xanthomonas citri pv. fuscans is one of the major threats to common bean crops (Phaseolus vulgaris L.). Resistance to CBB is particularly complex as 26 quantitative resistance loci to CBB have been described so far. To date, transcriptomic studies after CBB infection have been very scarce and the molecular mechanisms underlying susceptibility or resistance are largely unknown. Results: We sequenced and annotated the genomes of two common bean genotypes being either resistant (BAT93) or susceptible (JaloEEP558) to CBB. Reciprocal BLASTp analysis led to a list of 20,787 homologs between these genotypes and the common bean reference genome (G19833), which provides a solid dataset for further comparative analyses. RNA-Seq after inoculation with X. phaseoli pv. phaseoli showed that the susceptible genotype initiated a more intense and diverse biological response than the resistant genotype. Resistance was linked to upregulation of the salicylic acid pathway and downregulation of photosynthesis and sugar metabolism, while susceptibility was linked to downregulation of resistance genes and upregulation of the ethylene pathway and of genes involved in cell wall modification. Conclusions: This study helps better understanding the mechanisms occurring during the early colonization phase of common bean by Xanthomonas and unveils new actors potentially important for resistance and susceptibility to CBB. We discuss the potential link between the pathways induced during bean colonization and genes induced by transcription activator-like effectors (TALEs), as illustrated in other Xanthomonas pathovars.
Project description:Common bean (Phaseolus vulgaris L.) is a relevant crop cultivated over the world, largely in water insufficiency vulnerable areas. Since drought is the main environmental factor restraining worldwide crop production, efforts have been invested to amend drought tolerance in commercial common bean varieties. However, scarce molecular data are available for those cultivars of P. vulgaris with drought tolerance attributes. As a first approach, Pinto Saltillo (PS), Azufrado Higuera (AH), and Negro Jamapa Plus (NP) were assessed phenotypically and physiologically to determine the outcome in response to drought on these common bean cultivars. Based on this, a Next-generation sequencing approach was applied to PS, which was the most drought-tolerant cultivar to determine the molecular changes at the transcriptional level. The RNA-Seq analysis revealed that numerous PS genes are dynamically modulated by drought. In brief, 1005 differentially expressed genes (DEGs) were identified, from which 645 genes were up-regulated by drought stress, whereas 360 genes were down-regulated. Further analysis showed that the enriched categories of the up-regulated genes in response to drought fit to processes related to carbohydrate metabolism (polysaccharide metabolic processes), particularly genes encoding proteins located within the cell periphery (cell wall dynamics). In the case of down-regulated genes, heat shock-responsive genes, mainly associated with protein folding, chloroplast, and oxidation-reduction processes were identified. Our findings suggest that secondary cell wall (SCW) properties contribute to P. vulgaris L. drought tolerance through alleviation or mitigation of drought-induced osmotic disturbances, making cultivars more adaptable to such stress. Altogether, the knowledge derived from this study is significant for a forthcoming understanding of the molecular mechanisms involved in drought tolerance on common bean, especially for drought-tolerant cultivars such as PS.
Project description:P. syringae pv. phaseolicola is the causal agent of the halo blight disease of beans (Phaseolus vulgaris L). The disease attacks both foliage and pods of plant host. Many genes involve in pathogenicity and virulence are induced only in plant or in the presence of host components. In this work we investigated the effect of bean pod extract on the transcriptomic profile of the bacterium, when grown at low temperature in minimal medium with or without bean pod extract. Two RNA samples were compared, one prepared from cells grown in minimal medium M9 and the other from cells grown in minimal medium supplemented with bean pod extract.To control de biological variation that might interfere with data interpretation, a minimum of three biological replicates and two technical replicates (swap) were prepared.
Project description:To understand the molecular basis for differences of common bean wild-type and mutant in sulphur amino acid content, transcripts were profiled at four developmental stages of seeds from wild-type SARC1 and major seed storage protein-deficient line SMARC1N-PN1 using a CustomArray 90K array. Microarray data confirmed that transcripts of storage and sulphur-rich proteins and sulphur-metabolism related genes were differentially expressed between the lines. The common bean (Phaseolus vulgaris) mutant line, SMARC1N-PN1 and its wild type, SARC1 used in the microarray experiment were grown in the field in London, ON, in 2009. Four developmental stages of seeds, based on fresh seed weight, were harvested. The stages of seeds used are Stage IV M-bM-^@M-^S cotyledon, 25 mg seed weight; Stage V M-bM-^@M-^S cotyledon, 50 mg seed weight; Stage VI M-bM-^@M-^S maturation, 150 mg seed weight, corresponding to the most active phase of reserve accumulation; and Stage VIII M-bM-^@M-^S maturation, 380 mg seed weight, corresponding to the onset of desiccation, were harvested for total RNA extraction. Four biological replicates for Stage IV and V and 3 biological replicates for Stage VI and VIII.