BIO-INCROP

INNOVATIVE CROPPING TECHNIQUES TO INCREASE SOIL HEALTH IN ORGANIC FRUIT TREE CROP

Potential Response of Soil-Borne Fungal Pathogens Affecting Crops to a Scenario of Climate Change in Europe

A study was carried out on the potential response of soil-borne pathogens causing crop yield losses under a climate change scenario in Europe. A controlled chamber set of experiments was carried out to quantify pathogen response to temperature using pure colonies of three soil-borne fungi, representative of low (Fusarium nivale), medium-high (Athelia rolfsii) and high (Macrophomina phaseolina) temperature requirements. A generic model to simulate fungal growth response to temperature based on these experiments was developed and linked to a soil temperature model component, and to components to simulate soil water content accounting for crop water uptake of potential hosts. Pathogens relative growth was simulated over Europe using the IPCC A1B emission scenario as realization of the Hadley-CM3 global climate model, available from the European Commission and processed for use with biophysical models. The simulations resulting from using the time span centred on 2030 were compared to the baseline, centred on the year 2000, using a sample of 30 years of daily weather. The general trend of soil-borne pathogens response to the scenario of climate change is a relative increase in growth in colder areas of Europe, as a function of their temperature requirements. Projections of F. nivale in the future indicate a relative increase of this winter pathogen of wheat in Northern European countries. A. rolfsii and M. phaseolina, two soil-borne pathogens typical of warmer agricultural areas, could find more favourable conditions in areas of the Central Europe, but they differentiated in Southern Europe where A. rolfsii resulted affected by summer soil temperatures above optimum

Replant problems in South Tyrol: role of fungal pathogens and microbial populations in conventional and organic apple orchards

South Tyrol, the main Italian apple growing area, is characterised by an highly intensive soil cultivation. Previous investigations shows the existence of replant disorders although it has not been evaluated which are the main causes. A survey has been carried out in this area with two main aims I) to evaluate the role of soil borne pathogens in apple replant disease and II) to evaluate the effect of soil management toward soil borne pathogens causing replant diseases. The experimental sites were chosen in order to obtain three couples of contiguous conventional and organic apple orchards. Soil sickness test with young apple plants gave a significant growth reduction in all soil samples if compared to a peat control. Among all root colonising fungi (Fusarium oxysporum, F. solani, Aphanomyces sp., Cy/incrocarpon sp., Rhizoctonia sp. and Pythium sp.) some Rhizoctonia solani strains and all Pythium spp. were the most pathogenic. In all cases organic management seems to reduce the soil sickness severity caused by root rot fungal pathogens

BIO-INCROP PROJECT

BIO-INCROP web site is one deliverable n. 1 of Work package 0 ( coordination (D0.1). The home page shows nine links. Seven lead to forther pages describing the project(Partners, Work packages, meeting, publications, funding, contact), one is the link to Core Organic 2 web page, while the last one leads to a page aiming to give examples of the relationship between soil biodiversity and functionality to persons who are not specifically involved in research

D1.1 BIO-INCROP Report Disseminated at internal level. Apple replant disease (ARD) 1

Deliverable of activity performed in the first 12 months of BIO-INCROP project on WP 1- Task 1 Evaluation of biotic components involved in “replant disease” etiology

Auxin-mediated relationships between apple plants and root inhabiting fungi: impact on root pathogens and potentialities of growth-promoting populations.

This study aimed to elucidate the relationship between plant hosts and root-colonizing fungi recovered from apple orchard soils that had been replanted over multiple generations. Functional relationships of three groups of filamentous fungi (Ceratobasidium sp., Cylindrocarpon-like group and Fusarium acuminatum) with apple rootstocks were evaluated in plant growth bioassays. The Cylindrocarpon-like group and Ceratobasidium sp. showed a relationship with the host plant varying from pathogenic to commensal through to mutualistic for the latter group, while that of F. acuminatum tended to be mutualistic. Seven fungal isolates of each group, which induced the highest plant growth in bioassays, were evaluated for auxin (IAA) and gibberellin (GA3 and GA4) production in culture filtrate. All isolates of F. acuminatum as well as most of those of the Ceratobasidium sp. and ylindrocarpon-like groups produced IAA in culture filtrate. IAA production was evaluated for additional isolates of endophytic fungal species from fruit tree orchards and the functionality of IAA was confirmed by growing in vitro micropropagated plantlets of apple rootstock on MS medium supplemented with fungal culture filtrate. Findings from his study may explain the difficulty in defining the recise role of diverse root-colonizing fungal populations in replant disease aetiology of fruit tree orchards. However, the results demonstrate the presence of a positive and widely available biotic component of the orchard soil biology that may be exploited for the benefit of tree growth and production

Rhizosphere bacteria and fungi associated with plant growth in soils of three replanted apple orchards.

Background and aims: High-throughput 454 pyrosequencing was applied to investigate differences in bacterial and fungal communities between replant and closely situated control non-replant (fallow) soils. Methods The V1-V3 region of the bacterial 16S rRNA gene and the ITS1 region of fungi from the different soils were sequenced using 454 pyrosequencing (Titanium chemistry, and data were analysed using the MOTHUR pipeline. Results: The bacterial phyla Proteobacteria, Actinobacteria and Acidobacteria dominated in both fallow and replant apple orchard soils, and community composition at both phylum and genus level did not significantly differ according to NP-MANOVA. The fungal phyla Ascomycota, Zygomycota and Basidiomycota were dominant, and communities also did not differ in composition at either phylum or genus level. High positive Pearson correlations with plant growth in a plant growth assay performed with apple rootstocks plantlets were detected for the bacterial genera Gp16 and Solirubrobacter (r: >0.82) and fungal genera Scutellinia, Penicillium, Lecythophora and Paecilomyces (r: >0.65. Strong negative correlations with plant growth were detected for the bacterial genera Chitinophaga and Hyphomicrobium (r: <−0.78) and the fungal genera Acremonium, Fusarium and Cylindrocarpon (r: <−0.81. Conclusions: Study findings are in part consistent with those of previous research, but also highlight associations between apple plants and certain microbial genera. The functional role of these genera in affecting soil health and fertility should be further investigated

Rhizospheric changes of fungal and bacterial communities in relation to soil health of multi-generation apple orchards

The study focused on changes of rhizosphere microbial communities in apple trees in long-term replanted orchards of Central Europe, aiming at developing cropping practices to mitigate replant problems. It started from the evidence of a previous study which showed that a slight modification of root-colonizing fungal communities was responsible for a great increase of plant growth in soil samples which had previously been subjected to a gamma-irradiation cycle (25 kGy for 8 h), as compared to that observed in the corresponding untreated native soils. The study was performed on rhizospheric soil from nine multi-generation apple orchards after a plant growth assay with M9 rootstock plantlets. PCR-DGGE analysis of soil DNA was performed to evaluate fungal and bacterial communities in fallow and replanted soils, as well as corresponding gamma-irradiated samples. Findings showed that rhizospheric fungal and bacterial communities within apple orchards did not differ according to their position within the orchard; while, they showed a shift in the gamma-irradiated soils. Pseudomonas fluorescens, Pseudomonas tolasii, Pseudomonas spp. and Novosphingobium spp. were the bacteria which were mainly attributed to this change. A shifting in composition of Fusarium communities toward F. oxysporum and F. equiseti resulted the most linked to the changes at rhizosphere level after re-colonization; to the contrary, F. venenatum and F. venaceum, Truncatella sp. and Gibellulopsis sp., only occurred in native soils. Findings of this study suggest that disturbance events such as a gamma-irradiation can modify microbial communities in long-term apple orchards thus allowing a soil re-colonization suitable to increase soil suppressiveness

Potenzialit\ue0 d\u2019uso agricolo di reflui di estrazione dell'olio d\u2019oliva a due fasi.

Lo scopo del lavoro, realizzato nell'ambito del progetto europeo BIOTROLL , \ue8 stato quello di valutare il possibile utilizzo agricolo di tre diversi materiali residui dall\u2019estrazione dell'olio di oliva a due fasi. I composti utilizzati erano la "polpa di olive" (OP) residuo dell'estrazione dell'olio e due effluenti residui della fermentazione della OP per la produzione di idrogeno (EH2) e di metano (ECH4). In particolare, \ue8 stato studiato in una prova di laboratorio, il loro effetto sulle trasformazioni dell'azoto (N) nel suolo, misurando sia la variazione netta sia la mineralizzazione lorda dell\u2019N minerale, nonch\ue8 la variazione quantitativa delle popolazioni di funghi totali e di batteri culturabili. I risultati ottenuti hanno mostrato che OP ed EH2, ancora ricchi di substrati carboniosi, sono stati in grado di stimolare la crescita microbica, sia batterica che fingina, ed hanno provocato una forte immobilizzazione dell'N minerale nel primo periodo d\u2019incubazione, seguito da un lento rilascio. Al contrario, ECH4 non ha modificato, in maniera significativa rispetto al controllo, n\ue9 la dinamica dell'N minerale, n\ue9 la crescita microbica. Per quanto riguarda la mineralizzazione lorda, lo stimolo maggiore si \ue8 avuto con OP sia all'inizio che per circa met\ue0 del periodo d\u2019incubazione. Dai dati ottenuti sembra dunque molto promettente la possibilit\ue0 di impiegare questi reflui per la fertilizzazione delle colture tipiche dell\u2019area mediterranea