Project description:Transcriptional changes were monitored in roots of the barley cultivar Regina following inoculation with zoospores of the nonadapted plasmodiophorid virus vector Polymyxa betae using the Affymetrix Barley1 GeneChip®. Barley cv. Regina seeds were imbibed in distilled water over night and then transferred on to moist heat treated (90°C over night) sand in plastic trays that were sealed. Trays were incubated at room temperature for 4 days to allow the seeds to germinate to Zadocks stage 07 of the decimal code for the growth stages of cereals (Tottman et al., 1979 Annals of Applied Biology, 93: 221-234; Zadocks et al., 1974 Weed Research, 14: 415-421). 110 barley (cv. Regina) seedling (Zadocks stage 07) were placed into a 90 mm diameter plastic Petri dish (3 Petri dishes per treatment) and 60 mL of P. betae zoospore suspension added (1 x 10 6 spores mL-1). Control plants were treated exactly the same way except zoospore-free buffer (0.1 g L-1 Phostrogen, 0.5% Bovine serum albumen) was added. Zoospore challenge (and control) occurred at an ambient temperature of 22°C. Roots were excised from ten plants per treatment at ten time points (15’, 30’, 45’ 1h, 2h, 3h, 4h, 5h, 6h, 7h) and frozen in liquid nitrogen. Three independent biological replicate experiments were done. Total RNA was isolated from each sample using TRI-reagent following the manufacturer’s instructions (Invitrogen) and then treated with DNase I (Ambion, Texas, USA) according to the manufacturer’s protocol. RNA samples for microarray hybridisation were further purified using RNeasy Mini Spin column purification (Qiagen, Hilden, Germany). The integrity of the RNA samples was confirmed using the BioAnalyzer 2100 (Agilent Technologies). Affymetrix GeneChip processing, including RNA quality control, microarray hybridisation and data acquisition was performed through contract research services by Geneservice Ltd (www.geneservice.co.uk). A total of six hybridisations were performed. Publication: European Journal of Plant Pathology 123(1):5-15.<br> ****[PLEXdb(http://www.plexdb.org) has submitted this series at GEO on behalf of the original contributor, Graham McGrann. The equivalent experiment is BB75 at PLEXdb.]
Project description:Paenibacillus polymyxa is a root-associated plant growth-promoting rhizobacterium. It was reported that many strains of P. polymyxa naturally exhibited the phenotypic variation. In the phase variation, the characteristics of the wild-type ‘B’ and the variant ‘F’ are very different in sporulation formation, motility, antibiotic ability and so on. For better understanding of the actual physiological changes, we performed RNA-seq analyses of P. polymyxa E681 to compare genome wide patterns of gene expression. As a result, we obtained 1,062 differentially expressed genes related to flagellar assembly and transport systems.
Project description:Paenibacillus polymyxa is an agriculturally important plant growth promoting rhizobacterium (PGPR). Many Paenibacillus species are known to be engaged in complex bacteria-bacteria and bacteria-host interactions, which in other bacteria were shown to necessitate quorum sensing communication, but to date no quorum sensing systems have been described in Paenibacillus. Here we show that the type strain P. polymyxa ATCC 842 encodes at least 16 peptide-based communication systems. Each of these systems comprises a pro-peptide that is secreted to the growth medium and further processed to generate a mature short peptide. Each peptide has a cognate intracellular receptor of the RRNPP family, and we show that external addition of P. polymyxa communication peptides to the medium leads to reprogramming of the transcriptional response. We found that these quorum sensing systems are conserved across hundreds of species belonging to the Paenibacillaceae family, with some species encoding more than 25 different peptide-receptor pairs, representing a record number of quorum sensing systems encoded in a single genome.
Project description:Polymyxa betae belongs to the Plasmodiophorida (Phytomyxea, Rhizaria). Here, we report the first draft genome sequence of a member of the Polymyxa genus, which includes two obligate root endoparasite species, vectors of important soilborne plant viruses. The genome assembly was represented by 1,001 contigs, with a cumulated length of 27,085,946?bp.