Project description:Salmonella Heidelberg is currently the 9th common serovar and has more than twice the average incidence of blood infections in Salmonella. A recent Salmonella Heidelberg outbreak in chicken infected 634 people during 2013-2014, with a hospitalization rate of 38% and an invasive illness rate of 15%. While the company’s history suggested longstanding sanitation issues, the strains’ characteristics which may have contributed to the outbreak are unknown. We hypothesized that the outbreak strains of S. Heidelberg might possess enhanced stress tolerance or virulence capabilities. Consequently, we obtained nine food isolates collected during the outbreak investigation and several reference isolates and tested their tolerance to processing stresses, their ability to form biofilms, and their invasiveness in vitro. We further performed RNA-sequencing on three isolates with varying heat tolerance to determine the mechanism behind our isolates’ enhanced heat tolerance. Ultimately, we determined that (i) many Salmonella Heidelberg isolates associated with a foodborne outbreak have enhanced heat resistance (ii) Salmonella Heidelberg outbreak isolates have enhanced biofilm-forming ability under stressful conditions, compared to the reference strain (iii) exposure to heat stress may also increase Salmonella Heidelberg isolates’ antibiotic resistance and virulence capabilities and (iv) Salmonella Heidelberg outbreak-associated isolates are primed to better survive stress and cause illness. This data helps explain the severity and scope of the outbreak these isolates are associated with and can be used to inform regulatory decisions on Salmonella in poultry and to develop assays to screen isolates for stress tolerance and likelihood of causing severe illness.
Project description:Recent studies have shown that several plant species require microbial associations for stress tolerance and survival. In this work, we show that the desert endophytic bacterium Enterobacter sp. SA187 enhances yield and biomass of alfalfa in field trials, revealing a high potential for improving desert agriculture. To understand the underlying molecular mechanisms, we studied SA187 interaction with Arabidopsis thaliana. SA187 colonized surface and inner tissues of Arabidopsis roots and shoots and conferred tolerance to salt and osmotic stresses. Transcriptome, genetic and pharmacological studies revealed that the ethylene signaling pathway plays a key role in mediating SA187-triggered abiotic stress tolerance to plants. While plant ethylene production is not required, our data suggest that SA187 induces abiotic stress tolerance by bacterial production of 2-keto-4-methylthiobutyric acid (KMBA), known be converted into ethylene in planta. These results reveal a part of the complex molecular communication process during beneficial plant-microbe interactions and unravel an important role of ethylene in protecting plants under abiotic stress conditions.
Project description:A comparative study ware made to know the abiotic stress tolerance machanism between tolerant and susceptible plants at flowering stage. The tolerance in response to abiotic stresses are sum of expression of thousands of genes at a particular stage. Tomato plants were exposed to drought and heat stress for RNA extraction and hybridization on Affymetrix microarrays. To study the molecular mechanism of abiotic stress tolerance to increase the tolerance in tomato plants, transcripts of tolerant and susceptible plants at flowering stage were compared in response to heat and water stress.
Project description:Multiprotein bridging factor 1c MBF1c (At3g24500) is a stress-response transcription co-activator. To test the function of MBF1c, we over-expressed it in transgenic Arabidopsis plants using the 35S-CaMV promoter. T4 seeds form 3 independent lines were tested for their tolerance to biotic and abiotic stress conditions. Constitutive expression of MBF1c in Arabidopsis enhanced the tolerance of transgenic plants to bacterial infection, salinity, heat and osmotic stress. Moreover, the enhanced tolerance of transgenic plants to osmotic and heat stress was maintained even when these two stresses were combined. The expression of MBF1c in transgenic plants augmented the accumulation of a number of sugars and defense transcrtipts in response to heat stress. Transcriptome profiling and inhibitor studies suggest that MBF1c expression enhances the tolerance of transgenic plants to heat and osmotic stress by partially activating, or perturbing, the ethylene-response signal transduction pathway. MBF1 proteins could be used to enhance the tolerance of plants to different abiotic stresses. Suzuki et al., 2005 Plant Physiology, submitted. Experimenter name = Ron Mittler; Experimenter phone = 1-775-784-1384; Experimenter fax = 1-775-784-1650; Experimenter department = Dept. of Biochemistry; Experimenter institute = University of Nevada; Experimenter address = MS200; Experimenter address = Reno; Experimenter address = Nevada; Experimenter zip/postal_code = 89557; Experimenter country = USA Experiment Overall Design: 6 samples were used in this experiment
Project description:We did Genome wide RNA seq analysis between wild type MG1655 cells and mutant of bacterial poly(A) polymerase I (MG-pcnB null mutant). We show that pcnB-null mutation widely stabilises stress response mRNAs (>30%) and imparts cellular tolerance to multiple stresses.
Project description:Multiprotein bridging factor 1c MBF1c (At3g24500) is a stress-response transcription co-activator. To test the function of MBF1c, we over-expressed it in transgenic Arabidopsis plants using the 35S-CaMV promoter. T4 seeds form 3 independent lines were tested for their tolerance to biotic and abiotic stress conditions. Constitutive expression of MBF1c in Arabidopsis enhanced the tolerance of transgenic plants to bacterial infection, salinity, heat and osmotic stress. Moreover, the enhanced tolerance of transgenic plants to osmotic and heat stress was maintained even when these two stresses were combined. The expression of MBF1c in transgenic plants augmented the accumulation of a number of sugars and defense transcrtipts in response to heat stress. Transcriptome profiling and inhibitor studies suggest that MBF1c expression enhances the tolerance of transgenic plants to heat and osmotic stress by partially activating, or perturbing, the ethylene-response signal transduction pathway. MBF1 proteins could be used to enhance the tolerance of plants to different abiotic stresses. Suzuki et al., 2005 Plant Physiology, submitted. Experimenter name = Ron Mittler Experimenter phone = 1-775-784-1384 Experimenter fax = 1-775-784-1650 Experimenter department = Dept. of Biochemistry Experimenter institute = University of Nevada Experimenter address = MS200 Experimenter address = Reno Experimenter address = Nevada Experimenter zip/postal_code = 89557 Experimenter country = USA Keywords: genetic_modification_design; stimulus_or_stress_design
Project description:A comparative study ware made to know the abiotic stress tolerance machanism between tolerant and susceptible plants at flowering stage. The tolerance in response to abiotic stresses are sum of expression of thousands of genes at a particular stage.
Project description:Following pathogen infection, plants have developed diverse mechanisms of defense that enhance their immune system for more robust induction of defense responses against recurrent environmental stresses. This induced resistance can be heritable to the progeny, rendering them more tolerant to stressful events. Although within-generational induction of tolerance to abiotic stress is a well-documented phenomenon in virus-infected plants, the transgenerational inheritance of tolerance to abiotic stresses in their progenies has not been explored. Here, we show that infection of Nicotiana benthamiana plants by Potato virus X (PVX) and by a chimeric Plum pox virus (PPV) expressing the P25 protein of PVX (PPV-P25), but not by PPV, conferred tolerance to both salt and osmotic stresses to the progeny, which correlated with the level of virulence of the pathogen. This transgenerational tolerance to abiotic stresses in the progeny was partially sustained even if the plants experience a virus-free generation. Moreover, progenies from a Dicer-like3 mutant, irrespective whether their parents were infected or not, mimicked the enhanced tolerance to abiotic stress observed in progenies of PVX-infected wild-type plants, suggesting the involvement of 24-nt small interfering RNAs in the transgenerational tolerance to abiotic stress induced by virus infection. RNAseq analysis supported the upregulation of genes related to protein folding and response to stress in the progeny of PVX-infected plants. From an environmental point of view, the significance of virus-induced transgenerational tolerance to abiotic stress could be questionable, as its induction was offset by major reproductive costs arising from a detrimental effect on seed production
Project description:Global analysis of brassinosteroid (BR)-mediated gene expression under abiotic stress identifies BR associated mechanisms of stress tolerance, and new stress-related genes