Effect of microbial diversity on soil fungistasis, disease suppression and colonization by biological control agents
F. SCALA (1), G. Bonanomi (1), M. Capodilupo (1), M. Cennicola (1), M. Lorito (1)
(1) University of Naples “Federico II”, Portici, ITALY
Phytopathology 101:S160

Biodiversity strongly affects ecosystem functions such as productivity, stability and invasibility. Research efforts have been mostly focussed on terrestrial plant diversity, while little is known about soil microbial communities. This work aims to investigate the effects of microbial diversity on soil fungistasis, disease suppression and capability of non native microbes to colonize rhizhosfere. Synthetic microbial communities with species richness ranging from 1 to 8 were used in factorial experiments. Fungistasis was assessed by germination tests on various fungi (Aspergillus niger, Botrytis cinerea, Trichoderma harzianum), while disease suppression was assayed on the Pythium ultimum-tomato system. Invasiveness potential of Pseudomonas fluorescens was investigated using soil amended with crop residues or rhizospheres of three plants (wheat, tomato and alfa-alfa). Increasing levels of microbial diversity determined amount and stability increases of fungistasis and disease suppression. The capability of P. fluorescens to colonize soil and rhizosphere dramatically decreased with the species richness of the residential community. These results suggest that microbial diversity of communities affects their resistance to invasive species.