The pivotal role of cultivar affinity to arbuscular mycorrhizal fungi in determining mycorrhizal responsiveness to water deficit

Arbuscular mycorrhizal fungi (AMF) have gained remarkable importance, having been proved to alleviate drought stress-induced damage in wheat due to their ability to ameliorate plant water use efficiency and antioxidant enzyme activity. However, despite the current relevance of the topic, the molecular and physiological processes at the base of this symbiosis never consider the single cultivar affinity to mycorrhization as an influencing factor for the metabolic response in the AMF-colonized plant. In the present study, the mycorrhizal affinity of two durum wheat species (T. turgidum subsp. durum (Desf.)) varieties, Iride and Ramirez, were investigated. Successively, an untargeted metabolomics approach has been used to study the fungal contribution to mitigating water deficit in both varieties. Iride and Ramirez exhibited a high and low level of mycorrhizal symbiosis, respectively; resulting in a more remarkable alteration of metabolic pathways in the most colonised variety under water deficit conditions. However, the analysis highlighted the contribution of AMF to mitigating water deficiency in both varieties, resulting in the up- and down-regulation of many amino acids, alkaloids, phenylpropanoids, lipids, and hormones

Waste materials-based substrates for ornamental plant production: Technical and environmental aspects

In the plant nursery sector, efforts have been made for some time to partially or totally replace peat-based substrates with growing media characterized by a lower environmental impact. In this perspective it was decided to evaluate a composted material obtained from dredged sediments and green waste, to be used as component for substrates in ornamental plant production, while evaluating the environmental implications of this operation. Fresh green waste consisting of corn cob, wood chips, grass and leaves were mixed in different rates (3:1, 1:1, 1:3 v/v) with dried dredged sediments taken from a small stream located in an urban area (Čejkovice, Czech Republic). These different mixtures were co-composted for six months, and the compost heaps were managed following standard compost protocols. To evaluate the progress of the co-composting process, the various mixtures were subjected to physical, chemical and biological analysis, during the entire period of co-composting. Eventually these mixes were taken to a plant nursery farm in Pistoia (Tuscany, Central Italy), and mixed in different ratios with classical nursery growing media (peat and pumice). Then, one-year-old vegetatively propagated plants of two typical evergreen shrubs (Photinia × fraseri, Viburnum tinus) were placed in 10-L (24 Ø cm) pots with differentiated substrates, added with 4.5 g L-1 of Basacote®. The growth of the plants tested is monitored (dry mass storage); at the same time, it was decided to use an LCA (life cycle assessment) analysis, to quantify the CO2 emissions (kg CO2 equivalent) deriving from the different phases (inputs, energy, transport, structures, etc.) of the production process, assessing the effect of these growing mixes on the environmental sustainability of plant nursery production

The extracellular DNA can baffle the assessment of soil bacterial community, but the effect varies with microscale spatial distribution

Environmental DNA is made-up of intracellular (iDNA) and extracellular (eDNA) pools. In soils, eDNA can be present up to 40% and could distort the assessment of living microorganisms. Distribution of microbial community is inconsistent among different size-aggregates, and the persistence and turnover of eDNA are thus uneven. Uneven persistence and distribution of eDNA could lead to heterogeneity in community analysis biases that arise due to eDNA sequences at micro-scale distribution. Here, we investigated the diversity and structure of eDNA and iDNA bacterial communities in bulk soil and different size-aggregates. Significant differences were observed between eDNA and iDNA bacterial diversity and composition. Changes in community composition are more important than the amount of eDNA to assess the biases caused by eDNA in community analysis. Furthermore, variations were also observed in aggregates-levels for eDNA and iDNA community which indicates that colonization pattern of iDNA community and protection of eDNA through absorbance on particle surface within soil-matrix is heterogeneous. Our work provides empirical evidence that eDNA presence could mask the detection of aggregates-level spatial dynamics in soil microbial community and have potential to qualitatively baffle observed live effects of given treatment by adequately muting the actual response dynamics of the soil microbiome