Project description:In this experiment we measured the transcriptional response of tomato plants (cv “Money maker”) when attacked belowground by the nematode M. inognita and, subsequently, aboveground by different (and common for this crop) biotic agents. Three weeks-old plants were exposed to nematodes for 5 days. At the fifth day the terminal leaflet of one of the first two true leaves was infected with the Cauliflower Mosaic Virus, or with the pathogen, or with the potato aphid Macrosiphum euphorbiae, or with the CMV-infected M. euphorbiae. For each belowground/aboveground combination treatment a set of control plants that received only the aboveground treatment was prepared. The infected leaflets of 5 biological replicates, each consisting of 1 plant, were collected 1, 2, 3, 4, 5 and 6 days after the onset of the aboveground treatment and flash frozen in liquid nitrogen. A different set of plants was used for every time point. Corresponding leaves from plants that did not receive any aboveground treatment (control) were selected and sampled as described above. Three biological replicates were selected among the five for RNA isolation. Total RNA was sent for sequencing to BGI Hong Kong.
Project description:Aphids deliver saliva into plants and acquire plant sap for their nourishment using a specialized mouthpart or stylets. Aphid saliva is of great importance as it contains effectors that are involved in modulating host defense and metabolism. Although profiling aphid salivary glands and identifying secreted proteins have been successfully used, success in direct profiling of aphid saliva have been limited due to scarcity of saliva collected in artificial diets. Here we present the use of a neurostimulant, resorcinol, for inducing aphid salivation. Saliva of potato aphids (Macrosiphum euphorbiae), maintained on tomato, was collected in resorcinol diet, used in mass spectrometry and compared to the salivary proteome collected in water. Great majority of the proteins identified in the resorcinol diet were also present in the water diet and represented proteins with plethora of functions in addition to a large number of unknowns. About half of the salivary proteins were not predicted for secretion or had canonical secretion signal peptides. To further characterize M. euphorbiae saliva and identify effectors, salivary phosphoproteins were detected. Among these phosphorylated proteins were three known aphid effectors, Me_WB01635 /Mp1, Me10/Mp58 and Me23. In addition to insect proteins, tomato host proteins were also identified in aphid saliva. Our results indicate that aphid saliva is complex and provides a rich resource for functional characterization of effectors.
Project description:To investigate and compare the influence of root exudates of tomato and maize on Pseudomonas donghuensis P482, we have grown the strain up to a stationary phase in M9 0.4% glucose medium supplemented with maize exudates (Maize), tomato exudates (Tomato) or without supplementation (Control). We then performed differential gene expression analysis, identifying changes in transcriptome profiles between each treatment (Tomato, Maize) and the Control as reference conditions, and between the two treatments.
