Project description:The selective impact of pathogen epidemics on host defenses can be strong but remains transient. By contrast, life-history shifts can durably and continuously modify the balance between costs and benefits, which arbitrates the evolution of host defenses. Their impact, however, has seldom been documented. Here, we show with a simple mathematical model that the selective advantage of the defense system is expected to decrease with decreasing life span. We further document that, in natural populations of the model plant system Arabidopsis thaliana, the expression level of defense genes correlate positively with flowering time, a proxy for the length of vegetative life span. Using a genetic strategy to partition life span-dependent and –independent defense genes, we demonstrate that this positive co-variation is not explained by the pleiotropic action of major regulatory genes controlling both defense and life span. In agreement with our model, this study reveals that natural selection has likely assembled alleles promoting lower expression of defense genes with alleles decreasing the duration of vegetative life span in natural populations of A. thaliana. This is the first study demonstrating that life history evolution has a pervasive impact on the evolution of host immunity.
Project description:Plants have developed a complicated resistance system, and they exhibit various defense patterns in response to different attackers. However, the determine factors of plant defense patterns are still not clear. Here, we hypothesized that damage patterns of plant attackers play an important role in determining the plant defense patterns. To test this hypothesis, we selected leafminer, which has a special feeding pattern more similar to pathogen damage than chewing insects, as our model insect, and Arabidopsis thaliana as the response plants. The local and systemic responses of Arabidopsis thaliana to leafminer feeding were investigated using the Affymetrix ATH1 genome array.
Project description:We have implemented an integrated Systems Biology approach to analyze overall transcriptomic reprogramming and systems level defense responses in the model plant Arabidopsis thaliana during an insect (Brevicoryne brassicae) and a bacterial (Pseudomonas syringae pv. tomato strain DC3000) attack. The main aim of this study was to identify the attacker-specific and general defense response signatures in the model plant Arabidopsis thaliana while attacked by phloem feeding aphids or pathogenic bacteria. Defense responses and networks, unique and specific for aphid or Pseudomonas stresses were identified. Our analysis revealed a probable link between biotic stress and microRNAs in Arabidopsis and thus opened up a new direction to conduct large-scale targeted experiments to explore detailed regulatory links among them. The presented results provide a first comprehensive understanding of Arabidopsis - B. brassicae and Arabidopsis - P. syringae interactions at a systems biology level.
Project description:We have implemented an integrated Systems Biology approach to analyze overall transcriptomic reprogramming and systems level defense responses in the model plant Arabidopsis thaliana during an insect (Brevicoryne brassicae) and a bacterial (Pseudomonas syringae pv. tomato strain DC3000) attack. The main aim of this study was to identify the attacker-specific and general defense response signatures in the model plant Arabidopsis thaliana while attacked by phloem feeding aphids or pathogenic bacteria. Defense responses and networks, unique and specific for aphid or Pseudomonas stresses were identified. Our analysis revealed a probable link between biotic stress and microRNAs in Arabidopsis and thus opened up a new direction to conduct large-scale targeted experiments to explore detailed regulatory links among them. The presented results provide a first comprehensive understanding of Arabidopsis - B. brassicae and Arabidopsis - P. syringae interactions at a systems biology level.
Project description:Plants have developed a complicated resistance system, and they exhibit various defense patterns in response to different attackers. However, the determine factors of plant defense patterns are still not clear. Here, we hypothesized that damage patterns of plant attackers play an important role in determining the plant defense patterns. To test this hypothesis, we selected leafminer, which has a special feeding pattern more similar to pathogen damage than chewing insects, as our model insect, and Arabidopsis thaliana as the response plants. The local and systemic responses of Arabidopsis thaliana to leafminer feeding were investigated using the Affymetrix ATH1 genome array. Damaged leaves of Arabidopsis thaliana for local damage analysis and the intact leaves on the same plant for systemic damage analysis were separately frozen by liquid nitrogen. Then, we used an Affymetrix ATH1 Arabidopsis microarray to study the expression changes pattern of Arabidopsis thaliana to pea leafminers damage, both locally (LI) and systemically (SI). We downloaded data from the web database and used hierarchical clustering to explore the relationships of Arabidopsis thaliana expression pattern to different kinds of attackers.
Project description:DCA (3,5-Dichloroanthranilic acid) is a newly identified synthetic defense elicitor. To perform a comparative analysis of defense responses triggered by DCA and the structurally related defense inducer INA (2,6-Dichloroisonicotinic acid) Affymetrix chip experiments were performed with Arabidopsis thaliana seedlings treated with one of these two compounds.
Project description:Next generation sequencing was performed to identify genes changed in Arabidopsis thaliana upon Botrytis cinerea infection. The goal of the work is to find interesting genes involved in plant defense. The object is to reveal the molecular mechanism of plant defense.
Project description:Myzus persicae (green peach aphid) feeding on Arabidopsis thaliana induces a defense response, quantified as reduced aphid progeny production, in infested leaves but not in other parts of the plant. Similarly, infiltration of aphid saliva into Arabidopsis leaves causes only a local increase in aphid resistance. Further characterization of the defense-eliciting salivary components indicates that Arabidopsis recognizes a proteinaceous elicitor with a size between 3 to 10 kD. Genetic analysis using well-characterized Arabidopsis mutant shows that saliva-induced resistance against M. persicae is independent of the known defense signaling pathways involving salicylic acid, jasmonate, and ethylene. Among 78 Arabidopsis genes that were induced by aphid saliva infiltration, 52 had been identified previously as aphid-induced, but few are responsive to the well-known plant defense signaling molecules salicylic acid and jasmonate. Quantitative PCR analysis confirms expression of saliva-induced genes. In particular, expression of a set of O-methyltransferases, which may be involved in the synthesis of aphid-repellent glucosinolates, was significantly up-regulated by both M. persicae feeding and treatment with aphid saliva. However, this did not correlate with increased production of 4-methoxyindol-3-ylmethylglucosinolate, suggesting that aphid salivary components trigger an Arabidopsis defense response that is independent of this aphid-deterrent glucosinolate.
Project description:Plant volatiles can mediate plant-plant communication in the sense that plants attacked by herbivores can signal their unattacked neighbors of danger by emitting HIPVs. We call this the priming effect. Since the plant defense response is a systematic process involving numerous pathways and genes,to characterize the priming process, a time course study using a genome-wide microarray may provide more accurate information about the priming process. Furthermore, to what extent do the priming process and direct defense share similar gene expression profiles or pathways are also not clear. We used microarray to detect the priming effect of plant volatiles to healthy Arabidopsis thaliana, and the effect of direct leafminer feeding to Arabidopsis thalianas. A system using Lima bean plants, from which HIPVs can be effectively induced by leafminer feeding, as emitters and Arabidopsis thaliana as receivers is used to track the priming process between neighbor plants. The Arabisopsis thaliana seedlings were treated by volatiles from leafminer fed lima bean for 24h or 48h for RNA extraction and hybridization on Affymetrix microarrays. The Arabisopsis thaliana seedlings fed by leafminer directly were also collected The for RNA extraction and hybridization on Affymetrix micorarrays. We want to explore the response of Arabidopsis thaliana to priming volatiles during a 24h-48h time course. We also want to compare the effect of priming and direct leafminer feeding.