Long term evaluation of field-released genetically modified rhizobia.

This is the report of the first open field release of genetically modified microorganisms (GMMs) in Italy. It covers ten years of monitoring, and follows in-field GMM dynamics from strain release to disappearance below detection limits, as well as assessment of impact on resident microorganisms. The bacteria released belong to the nitrogen fixing legume endosymbiont Rhizobium leguminosarum bv.

Self-anastomosing ability and vegetative incompatibility of Tuber borchii isolates.

In this work, different mycelial isolates of the ectomycorrhizal fungus Tuber borchii were analysed for their ability to form self-anastomoses, which were monitored by time-lapse live-cell imaging, providing a description of the anastomosis process. Self-fusions were evidenced in three out of five isolates, with frequencies ranging between 50 and 88% of hyphal contacts. Time-lapse video microscopy evidenced that during pre-contact events, hyphae were capable of growth re-orientation functional to hyphal contact: the time elapsed between hyphal growth re-direction and complete fusion ranged from 115 to 200 min.

Pseudomonas fluorescens 134 as a biological control agent (BCA) model in cell immobilization technology.

Antifungal activity against Rhizoctonia solani was achieved in vivo through the application of Pseudomonas fluorescens strain 134 encapsulated in sodium alginate beads of different sizes (0.5, 1, and 2 mm). The activity was compared to that obtainable with chemical treatments and bead-derived liquid formulations.

Rhizobium sullae sp. nov. (formerly 'Rhizobium hedysari'), the root-nodule microsymbiont of Hedysarum coronarium L.

This work is the completion of a series of reports describing the nitrogen-fixing bacterial symbionts of sulla (Hedysarum coronarium L., Leguminosae) and providing the grounds for their proposal as a new taxon. The introduction summarizes a large amount of previous evidence gathered on the physiology, genetics and ecology of such organisms, which have in the past been referred to provisionally as 'Rhizobium hedysari'.

Diversity of culturable bacterial populations associated to Tuber borchii ectomycorrhizas and their activity on T. borchii mycelial growth.

Isolation and physiological and molecular characterisation of culturable bacterial strains belonging to actinomycetes, pseudomonads and aerobic spore-forming bacteria were carried out on mycorrhizal root tips of Quercus robur var. peduncolata infected by Tuber borchii. Cellular density of the three bacterial groups in ectomycorrhizal root tips was estimated to be 1.

The occurrence of anastomosis formation and nuclear exchange in intact arbuscular mycorrhizal networks.

•  The widespread occurrence of anastomoses and nuclear migration in intact extraradical arbuscular mycorrhizal (AM) networks is reported here. •  Visualization and quantification of intact extramatrical hyphae spreading from colonized roots into the surrounding environment was obtained by using a two-dimensional experimental model system. •  After 7 d the length of extraradical mycelium in the AM symbiont Glomus mosseae ranged from 5169 mm in Thymus vulgaris to 7096 mm in Prunus cerasifera and 7471 mm in Allium porrum, corresponding to 10, 16 and 40 mm mm root length, respectively.