Project description:Background: The biological control agent Pseudomonas chlororaphis PA23 is effective at protecting Brassica napus (canola) from the necrotrophic fungus Sclerotinia sclerotiorum via direct antagonism. Despite the growing importance of biocontrol bacteria in plant protection from fungal pathogens, little is known about how the host plant responds to bacterial priming on the leaf surface or about changes in gene activity genome-wide in the presence and absence of S. sclerotiorum. Results: PA23 priming of mature canola plants reduced the number of lesion forming petals by 90%. Global RNA sequencing of the host pathogen interface showed a reduction in the number of genes uniquely upregulated in response to S. sclerotiorum by 16-fold when pretreated with PA23. Upstream defense-related gene patterns suggest MAMP-triggered immunity via surface receptors detecting PA23 flagellin and peptidoglycans. Although systemic acquired resistance was induced in all treatment groups, a response centered around a glycerol-3-phosphate (G3P)-mediated pathway was exclusively observed in plants treated with PA23 alone. Activation of these defense mechanisms by PA23 involved mild reactive oxygen species production as well as pronounced thylakoid membrane structures and plastoglobule formation in leaf chloroplasts. Conclusion: Further to the direct antibiosis that it exhibits towards the pathogen S. sclerotiorum, PA23 primes defense responses in the plant through the induction of unique local and systemic defense regulatory networks. This study has shed light on the potential effects of biocontrol agents applied to the plant phyllosphere. Understanding these interactions will aid in the development of biocontrol systems as a viable alternative to chemical pesticides in the protection of important crop systems.
Project description:Insect pathogenic fungus Beauveria bassiana in one of the best studied insect biocontrol fungus, which infects insects by cuticle penetration. After breaking the cuticles, the fungus will propagate in insect hemocoel and kill insect hosts. It has also been found that the mycelia of B. bassiana can penetrate plant tissues to reach insect inside plant, e.g. corn borer (Ostrinia furnacalis), but do not cause damage to plants. The mechanism of fungal physiological plasticity is poorly understood. To accompany our genome sequencing work of B. bassiana strain ARSEF 2860, fungal transcriptional responses to different niches were studied using an Illumina RNA_seq technique. To examine fungal response to insect cuticle, conidia were inoculated on locust hind wings for 24 hours before used for RNA extraction. To evaluate fungal adaptation to insect hemocole, the fifth instar larvae of cotton bollworms were injected with spore suspension and fungal cells isolated by centrifugation in a step gradient buffer. To unveil the mechanism of interaction with plants, the fungus was grown in corn root exudates for 24 hours. After RNA sequencing, around three million tags were acquired for each sample and fungal transcriptional profiles were compared. Unveiling gene differential expression patterns when the insect biocontrol fungus Beauveria bassiana grown in insect hemocoel, corn root exudates and on insect cuticles.
Project description:Transcriptional changes occurring at the infection site of 2 weeks old Cabernet sauvignon grapevine cuttings infected with a wood pathogen (Phaeomoniella chlamydospora) in the presence of a root-inoculated biocontrol agent (Pythium oligandrum). Gene expression profiling was done using the Nimblegen whole genome array with 3 biological replicates of 3 pooled wood chunks harvested 0 and 14 d after treatment (pathogen infection, biocontrol agent inoculation, mock treatment).
Project description:The current lack of proven pharmacological treatment options for traumatic brain injury (TBI) patients reflects the poor translation of successful preclinical studies in clinical trials. This may be due to poor choice of therapeutic agents based on incomplete knowledge of critical elements of neuroprotection. Our goal is to expedite discovery and translation of therapeutic agents that can improve functional outcome by identifying the common molecular profile of neuroprotective drugs. Since damage to the hippocampus is associated with TBI-induced deficits in learning and memory, we analyzed of the hippocampal transcriptional profiles of TBI rats treated with two clinically used drugs metyrapone and carbenoxolone, which have been shown to improve cognitive deficits in previous studies. Despite their different structures, we found that MT and CB have similar effects on several known biological pathways. The neuroprotective effects of these drugs are associated with a distinctive molecular signature which is characterized not by changes in expression of any individual gene but by a common global effect on multiple cell signaling pathways. These data suggest that drug treatments that induce a coordinated attenuation of multiple injury-induced cell signaling networks, both deleterious and protective, have high translational potential.
Project description:The free-living soil fungus Trichoderma hamatum GD12 is notable amongst other Trichoderma strains in exhibiting both biocontrol and plant growth promotion (PGP) activities, which are coincident with a markedly expanded genome when compared to other characterised biocontrol and PGP isolates. Here, we make direct comparisons of T. hamatum GD12 transcription during PGP, and during antagonism of the root-infecting pathogen Sclerotinia sclerotiorum, in peat-based microcosms. An extensive mRNA-seq analysis sampling six time-points, 1, 2, 4, 7, 10 and 15 days after microcosm establishment revealed dynamic and biphasic signatures in the transcriptional responses of T. hamatum GD12 during Sclerotinia biocontrol and lettuce growth promotion. Functional analysis of differentially expressed genes demonstrated up-regulation of transportation and oxidation-reduction genes during both processes. Sclerotinia biocontrol is most likely mediated by the synthesis and secretion of antifungal compounds. Notably, the biphasic response during biocontrol was further characterised by the expression of a number of uncharacterised GD12 genes, small-secreted cysteine rich proteins and secondary metabolite producing gene clusters. This work demonstrates that T. hamatum GD12 harnesses a reservoir of uncharacterised genes that are actively engaged during effective biological control of a plurivorous plant pathogen.
Project description:The current lack of proven pharmacological treatment options for traumatic brain injury (TBI) patients reflects the poor translation of successful preclinical studies in clinical trials. This may be due to poor choice of therapeutic agents based on incomplete knowledge of critical elements of neuroprotection. Our goal is to expedite discovery and translation of therapeutic agents that can improve functional outcome by identifying the common molecular profile of neuroprotective drugs. Since damage to the hippocampus is associated with TBI-induced deficits in learning and memory, we analyzed of the hippocampal transcriptional profiles of TBI rats treated with two clinically used drugs metyrapone and carbenoxolone, which have been shown to improve cognitive deficits in previous studies. Despite their different structures, we found that MT and CB have similar effects on several known biological pathways. The neuroprotective effects of these drugs are associated with a distinctive molecular signature which is characterized not by changes in expression of any individual gene but by a common global effect on multiple cell signaling pathways. These data suggest that drug treatments that induce a coordinated attenuation of multiple injury-induced cell signaling networks, both deleterious and protective, have high translational potential. There were 16 samples for array analysis, two biological replicates each for control (4 and 24 hour), TBI (4 and 24 hour), TBI plus MT (4 and 24 hour) and TBI plus CB (4 and 24 hour). Each biological sample, which is a pooled RNA sample (laser captured CA3 pyramidal neurons) from the hippocampus of 3-6 rats, was hybridized to duplicate arrays so that there were 32 gene arrays in this study.