Project description:Brassica nigra plants, a Brassicaceae close to Arabidopsis thaliana, was used for combined stresses experiments. In this study, we performed a whole-genome microarray analysis on five-week-old plants and compared untreated plants and plants treated different single or dual stresses: the larvae Pieris brassicae, egg extract of Pieris brassicae, the bacterial Xanthomonas campestris pv. raphani, the aphid Brevicoryne brassicae or by combined stresses eggs of P. brassicae / P. brassicae, X. campestris / P. brassicae, B. brassicae / P. brassicae.
Project description:Although a seemingly harmless developmental stage of herbivores, insect eggs trigger efficient plant defenses that include necrosis, callus formation, accumulation of ovicidal compounds and release of volatiles to attract egg predators. The large white butterfly Pieris brassicae deposits batches of 20-30 eggs onto Arabidopsis leaves, causing a large transcriptional reprograming that is drastically distinct from the expression profile triggered by larval feeding. Also, P. brassicae eggs induce localized cell death, accumulation of reactive oxygen species (ROS) and salicylic acid (SA), and expression of PTI-related genes, suggesting that egg-associated molecular patterns (EAMPs) activate a response that is similar to the response induced by microbial pathogens. We previously reported that a crude P. brassicae egg extract (EE, soluble fraction from crushed eggs) induced similar responses as oviposition, including ROS and SA accumulation, cell death and defense gene induction. In order to compare oviposition and EE treatment at the transcriptome level, we analyzed changes in transcipt abundance with P. brassicae EE or after natural oviposition. After 5 days, hundreds of genes were significantly upregulated by each treatment and their induction was highly similar between treatments. This conserved transcriptomic signature thus strongly supports our previous observations that oviposition and EE treatment trigger comparable responses in Arabidopsis.
Project description:To investigate the impact of a plant´s response to abiotic stress on plant defense against subsequent biotic stress, we determined the transcriptional response of Arabidopsis thaliana to low temperature stress (4°C) and subsequent mechanical wounding or larval feeding damage by the herbivores Mamestra brassicae (generalist) and Pieris brassicae (specialist). In total, 21%, 4% and 14% of all genes responsive to M. brassicae, P. brassicae or mechanical wounding were differentially regulated in previously cold-treated compared to untreated plants.
Project description:Brassica nigra plants, a Brassicaceae close to Arabidopsis thaliana, was used for combined stresses experiments. In this study, we performed a whole-genome microarray analysis on five-week-old plants and compared untreated plants and plants treated with ozone at 70 ppb, larvae of Pieris brassicae or both ozone followed by P. brassicae insect.
Project description:Plants can cope with stress better if they experience a mild form of the stress before the actual \\"real\\" stress event. In Arabidopsis thaliana it is known that plants that harboured eggs of the White cabbage butterfly (Pieris brassicae) before larval feeding can defend better against the herbivore stress. The main aim of the experiment was to compare the priming effect induced by insect egg deposition of Pieris brassicae between vegetative and reproductive (first open flowers) Arabidopsis thaliana plants on the transcriptional level. We used a full factorial setup consisting of a) untreated control plants , b) plants which experienced eggs for 6 days without larval feeding after that period, c) plants which experienced no eggs before larval feeding for 24 hours d) plants which experienced eggs for 6 days and larval herbivory for 24 hours. This setup was conducted with 6 week old vegetative plants and 10 week old reproductive plants were the first flowers were open. For all treatments leaf tissue from the leaves that experienced egg oviposition and/or larval feeding were collected. From reproductive plants flower buds were collected as well.
