Project description:This study describes physiological changes, morphological adaptations and the regulation of pathogen defense responses in Arabidopsis crown galls. Crown gall development was induced on intact plants under most natural conditions with Agrobacterium tumefaciens. Differential gene expression and the metabolite pattern was determined by comparing crown galls with mock-inoculated inflorescence stalk segments of the same age.
Project description:The intention of these gene expression analysis was to study host responses to an infection with Agrobacterium tumefaciens at different stages of crown gall development. Therefore the transcriptome of infected inflorescence stalk tissue and mature crown galls of Arabidopsis thaliana (WS-2) was determined of three different time points. These were compared with the transcriptome of mock-infected inflorescence stalk tissue (reference) of the same age. The following time points were analyzed: (i) three hours post inoculation, before the T-DNA is integrated into the host genome (ii) six days after inoculation when the T-DNA is present in the nucleus and the oncogenes are expressed in the host cell, and (iii) 35 days after inoculation when a mature tumors has developed. For the three-hour- (3hpi) and six-day- time point (6dpi) plants were infected with the virulent strain C58, harboring a T-DNA, or with strain GV3101, containing a disarmed Ti-plasmid. This allows discrimination between signals which derive from the bacterial pathogen and the T-DNA encoded oncogenes. This SuperSeries is composed of the following subset Series:; GSE13929: Arabidopsis thaliana three hours after infection with Agrobacterium tumefaciens; GSE13930: Arabidopsis thaliana six days after infection with Agrobacterium tumefaciens; GSE13927: Transcriptome of mature A. thaliana crown galls. Experiment Overall Design: Refer to individual Series
Project description:Glyphosate is known to inhibit 5-enolpyruvylshikimate-3-phosphate synthase of the chorismate biosynthetic pathway, and chorismate is a precursor to aromatic amino acids, auxin, and many other secondary products. Although the perennial weed leafy spurge (Euphorbia esula L.) is considered glyphosate tolerant, glyphosate is often used as part of an integrated pest management program in non-cultivated ecosystems of North America. Part of its tolerance is attributed to escape through an abundance of underground adventitious buds (UABs). Sub-lethal concentrations of foliar applied glyphosate leads to new shoot growth from UABs that have a stunted and/or bushy phenotype after growth-inducing decapitation. To gain insights into glyphosateM-bM-^@M-^Ys impact on molecular mechanisms associated with the stunted and bushy phenotype, we obtained global transcriptome abundance using RNAseq from a subsequent generation of aerial shoots derived from crown buds of glyphosate-treated and -untreated leafy spurge. We further correlated transcript abundance to accumulation of shikimate and phytohormones from the same samples to elucidate interactions. Abundance of shikimate was similar in subsequent generations of aerial shoots generated from crown buds of treated and untreated plants and is likely not a direct factor leading to the stunted and bushy phenotype. However, the results do suggest that transcripts involved in auxin transport and signaling and crosstalk with other phytohormones likely play a role in the bushy phenotype. The results of this study provide some insights for identifying new targets for manipulation of plant growth and development. Transcriptome and metabolite profiling are obtained for aerial tissues derived from crown buds of foliar glyphosate-treated and control (2.24 or 0 kg/ha active ingredient glyphosate + 0.25% v/v surfactant) leafy spurge plants. Each experiment included 4 biological replicates.