The transcriptome of the arbuscular mycorrhizal fungus Glomus intraradices (DAOM 197198) reveals functional tradeoffs in an obligate symbiont.

• The arbuscular mycorrhizal symbiosis is arguably the most ecologically important eukaryotic symbiosis, yet it is poorly understood at the molecular level. To provide novel insights into the molecular basis of symbiosis-associated traits, we report the first genome-wide analysis of the transcriptome from Glomus intraradices DAOM 197198. • We generated a set of 25,906 nonredundant virtual transcripts (NRVTs) transcribed in germinated spores, extraradical mycelium and symbiotic roots using Sanger and 454 sequencing. NRVTs were used to construct an oligoarray for investigating gene expression. • We identified transcripts coding for the meiotic recombination machinery, as well as meiosis-specific proteins, suggesting that the lack of a known sexual cycle in G. intraradices is not a result of major deletions of genes essential for sexual reproduction and meiosis. Induced expression of genes encoding membrane transporters and small secreted proteins in intraradical mycelium, together with the lack of expression of hydrolytic enzymes acting on plant cell wall polysaccharides, are all features of G. intraradices that are shared with ectomycorrhizal symbionts and obligate biotrophic pathogens. • Our results illuminate the genetic basis of symbiosis-related traits of the most ancient lineage of plant biotrophs, advancing future research on these agriculturally and ecologically important symbionts.

Operative treatment of subcortical metastatic tumours in the central region.

The operative treatment of subcortical metastatic tumours within the paracentral area is still under discussion. Against the background of possible new postoperative neurological deficits and of evolving new radio oncological techniques, the indication for surgery is limited only to a subgroup of patients. In this retrospective study we present the clinical results after operative treatment of metastases within the central and paracentral brain region, with an emphasis on the short-term and mid-term functional outcome. We report on 20 patients suffering from subcortical brain metastases within the primary sensorimotor area, with a median volume on MRI-scans of 8.18 cm³. Patients were admitted to our department with a progressive hemiparesis (n = 11), focal seizures (n = 6) or other unspecific symptoms (n = 3) like headache, nausea, and neuropsychological disturbances, respectively. After updated MRI- and fMRI-scanning, intensive electrophysiological testing including MEP-brain mapping and interdisciplinary tumour-board discussion of each case, those patients were evaluated for surgery. Early postoperative control was done by MRI within the first 48 h. Follow-up took place in our outpatient department, assessing clinical criteria two and 6 weeks postoperatively, followed by clinical control and MRI-scans every 3 months. In all patients, surgery was performed under general anaesthesia, cranial neuro navigation and intraoperative motor cortex stimulation. Surgery and the early postoperative course were uneventful in all cases. After a 6 months follow-up, two patients had died. The motor deficits improved in seven patients and remained unchanged in four cases. One patient suffered from a new persistent hemiparesis. A temporary paresis occurred in two cases. In five patients there was no motor deficit pre- and postoperatively. The Karnofsky Performance Status improved in ten patients 6 months after surgery. Quality of Life, measured by the FACT-Br score, improved in 12 patients and remained unchanged in one patient. With modern techniques like fMRI-guided cranial neuronavigation and intraoperative neuromonitoring including direct stimulation of the motor cortex, microsurgical resection of subcortical paracentral metastases is feasible with an acceptable risk of neurological deterioration. Even preexistent deficits can improve with positive influence on the quality of life for oncological patients, being disabled by the symptoms caused by the cerebral lesion.

Development of a specific PCR assay for the detection of Rhizoctonia solani AG 1-IB using SCAR primers.

AIMS: The aim of this study was to develop a specific and sensitive identification method for Rhizoctonia solani AG 1-IB isolates based on phylogenetic relationships of R. solani AG-1 subgroups using rDNA-internal transcribed spacer (rDNA-ITS) sequence analysis. METHODS AND RESULTS: A neighbour-joining tree analysis of 40 rDNA-ITS sequences demonstrated that R. solani AG-1 isolates cluster separately in six subgroups IA, IB, IC, ID, IE and IF. A molecular marker was generated from a random amplified polymorphic DNA fragment (RAPD). After conversion into a sequence-characterized amplified region (SCAR), a specific primer set for identification of subgroup AG 1-IB was designed for use in a polymerase chain reaction (PCR). The primer pair amplified a single DNA product of 324 bp. CONCLUSIONS: R. solani AG-1 subgroups were discriminated by sequence analysis of the ITS region. The designed SCAR primer pair allowed an unequivocal and rapid detection of R. solani AG 1-IB in plant and soil samples. SIGNIFICANCE AND IMPACT OF THE STUDY: Sequence analysis of the rDNA-ITS region can be used for differentiation of subgroups within AG-1. The use of the developed SCAR primer set allowed a reliable and fast identification of R. solani AG 1-IB and provides a powerful tool for disease diagnosis.

Identification of heavy metal-induced genes encoding glutathione S-transferases in the arbuscular mycorrhizal fungus Glomus intraradices.

Arbuscular mycorrhizal fungi are able to alleviate the stress for plants caused by heavy metal contamination of soil. To analyze the molecular response of arbuscular mycorrhizal fungi to these pollutants, a subtractive cDNA library was constructed using RNA from Glomus intraradices extraradical hyphae of a root organ culture treated with a mixture of Cd, Zn, and Cu. Screening by reverse Northern blot analysis indicated that, among 308 clones, 17% correspond to genes up-regulated by heavy metals. Sequence analysis of part of the clones resulted, amongst others, in the identification of six genes putatively coding for glutathione S-transferases belonging to two different classes of these enzymes. Expression analyses indicated that the genes are differentially expressed during fungal development and that their RNA accumulation dramatically increases in extraradical hyphae grown in a heavy metal-containing solution.