Host genotype and health status influence on the composition of the arbuscular mycorrhizal fungi in Salix bioenergy plantations

• A molecular-based approach to study root-associated AM fungi of Salix cultivars.
• AMF composition is directly related to Salix phylogeny as specific to willow cultivars.
• AMF abundance and diversity higher in healthy compared to diseased plants.
• AMF may have important ecological implications for willow biomass production.

In agricultural production systems, fast-growing trees such as willow (Salix spp.) have gained popularity as a sustainable source of bioenergy and bioproducts. Among the diverse fungi in symbiosis with roots of willow, arbuscular mycorrhizal fungi (AMF) may play a crucial role in the establishment and growth of willow in short rotation intensive cultures (SRIC). An approach based on the denaturing gradient gel electrophoresis (DGGE) technique was developed to study AMF communities and their effect on Salix growth and disease resistance in SRIC. The DGGE patterns and the sequences of major DGGE bands obtained with the large subunit rDNA primer set (LSU) showed an important shift in diversity of AMF communities in healthy compared to diseased plants. The AMF communities consisted of Glomus sp., G. clarum, G. claroideum, G. mosseae, G. geosporum-G. cf. diaphanum complex, Rhizophagus irregularis (syn. Glomus irregulare/G. intraradices) and Glo-S, a possible undescribed glomeromycete species. The structure of AMF communities, as well as possible role of each AMF taxon, appeared to be dependent upon the cultivar to which they associate. This calls attention to consider the ecological implications, for biomass production, of the specificity of the association between particular willow cultivars and AMF.