Soil microbiota respond to green manure in organic vineyards.

AIMS: The aim of this work was to investigate the effects of biodynamic management with and without the addition of green manure, in comparison with organic management, on the microbiota in vineyards soil. METHODS AND RESULTS: High throughput sequencing was used to compare the taxonomic structure of the soil bacterial and fungal communities from vineyards managed with different methods (organic, biodynamic or biodynamic with green manure). Our results showed that microbial communities associated with biodynamic and organic farming systems were very similar, while green manure was the greatest source of soil microbial biodiversity and significantly changed microbial richness and community composition compared with other soils. Green manure also significantly enriched bacterial taxa involved in the soil nitrogen cycle (e.g. Microvirga sp., Pontibacter sp. and Nitrospira sp.). CONCLUSIONS: Our results showed that the diversity and composition of the microbial communities associated with biodynamic and organic farming systems were similar, indicating that the use of biodynamic preparations 500 and 501 did not cause any significant detectable changes to the soil microbial community in the short term, while the effects of green manure were significant in soil microbiota. SIGNIFICANCE AND IMPACT OF THE STUDY: The microbiological richness and structure of soil are used as a sensitive indicator of soil quality. The extension of organic/biodynamic farming, associated with green manure application, could contribute to increase the abundance of functional groups of biological and agronomical relevance and maintaining microbial biodiversity in vineyard soils.

Fungal Planet description sheets: 128-153.

Novel species of microfungi described in the present study include the following from Australia: Catenulostroma corymbiae from Corymbia, Devriesia stirlingiae from Stirlingia, Penidiella carpentariae from Carpentaria, Phaeococcomyces eucalypti from Eucalyptus, Phialophora livistonae from Livistona, Phyllosticta aristolochiicola from Aristolochia, Clitopilus austroprunulus on sclerophyll forest litter of Eucalyptus regnans and Toxicocladosporium posoqueriae from Posoqueria. Several species are also described from South Africa, namely: Ceramothyrium podocarpi from Podocarpus, Cercospora chrysanthemoides from Chrysanthemoides, Devriesia shakazului from Aloe, Penidiella drakensbergensis from Protea, Strelitziana cliviae from Clivia and Zasmidium syzygii from Syzygium. Other species include Bipolaris microstegii from Microstegium and Synchaetomella acerina from Acer (USA), Brunneiapiospora austropalmicola from Rhopalostylis (New Zealand), Calonectria pentaseptata from Eucalyptus and Macadamia (Vietnam), Ceramothyrium melastoma from Melastoma (Indonesia), Collembolispora aristata from stream foam (Czech Republic), Devriesia imbrexigena from glazed decorative tiles (Portugal), Microcyclospora rhoicola from Rhus (Canada), Seiridium phylicae from Phylica (Tristan de Cunha, Inaccessible Island), Passalora lobeliae-fistulosis from Lobelia (Brazil) and Zymoseptoria verkleyi from Poa (The Netherlands). Valsalnicola represents a new ascomycete genus from Alnus (Austria) and Parapenidiella a new hyphomycete genus from Eucalyptus (Australia). Morphological and culture characteristics along with ITS DNA barcodes are also provided.

An intact soil-core microcosm method to evaluate the survival and vertical dispersal of Trichoderma atroviride SC1.

AIM: To develop an intact soil-core microcosm method to study the survival and vertical dispersal of an experimental biocontrol agent (Trichoderma atroviride SC1) applied to the soil surface. METHODS AND RESULTS: The soil for the microcosms was collected using iron pipes with perforations corresponding to different soil layers. The tool was inserted into the soil and gently removed with the soil core inside. Trichoderma atroviride SC1 was mixed with the top layer of soil in the pipe. The experiment was performed in 2006 and 2007, and data from the microcosms were compared with results obtained under field conditions in the locations in which, the microcosms were collected, in the same periods. The concentrations of T. atroviride SC1 in the soil were estimated immediately after treatment, and 1, 5, 9 and 18 weeks after treatment at both the soil surface and the above-mentioned depths. The development of T. atroviride SC1 populations in the microcosms during the 18 weeks of monitoring was similar to that observed under field conditions. The dispersal of conidia was affected by the application of water to the soil. CONCLUSIONS: Results demonstrate that this microcosm prototype can be used to model the behaviour of T. atroviride SC1 in soil. SIGNIFICANCE AND IMPACT OF THE STUDY: The intact soil-core microcosm is a reliable, easy-to-use, fast and cheap method that could also be used in studies of similar filamentous fungi to study their probable fate in the soil prior to their being introduced into the environment.

Evaluating the survival and environmental fate of the biocontrol agent Trichoderma atroviride SC1 in vineyards in northern Italy.

AIMS: To study the survival in the soil and the dispersion in the environment of Trichoderma atroviride SC1 after soil applications in a vineyard. METHODS AND RESULTS: Trichoderma atroviride SC1 was introduced into soil in two consecutive years. The levels of T. atroviride populations at different spatial and temporal points following inoculation were assessed by counting the colony-forming units and by a specific quantitative real-time PCR. A high concentration of T. atroviride SC1 was still observed at the 18th week after inoculation. The vertical migration of the fungus to a soil depth of 0.4 m was already noticeable during the first week after inoculation. The fungus spread up to 4 m (horizontally) from the point of inoculation and its concentration decreased with the increasing distance (horizontal and vertical). It was able to colonize the rhizosphere and was also found on grapevine leaves. One year after soil inoculation, T. atroviride SC1 could still be recovered in the treated areas. CONCLUSIONS: Trichoderma atroviride SC1 survived and dispersed becoming an integrant part of the local microbial community under the tested conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: The persistence and rapid spread of T. atroviride SC1 represent good qualities for its future use as biocontrol agent against soilborne pathogens.