Raffaella Morelli

Soil biodiversity in apple orchards plays a vital role for productivity. We studied the biodiversity of prokaryotes, protists and fungi of 26 apple orchards belonging to the same regional growers' association in Northern‐Italy by environmental DNA metabarcoding (16S, 18S, ITS). We assessed alpha‐ and beta‐diversity, distance decay relationships, immigration rates and community assembly processes, variance partitioning between space and environment and putative prokaryotic and fungal functions from the upper 20 cm of soil during summer 2023. Despite uniform management practices, orchards showed a huge variability in alpha diversity, with single orchards having only a small part of total diversity. Protists showed the lowest mean beta‐diversity, followed by prokaryotes and fungi. Although immigration rates were low across all organismal groups—reflecting the low number of taxa co‐occurring across all orchards—prokaryotes and protists still displayed relatively higher rates than fungi, in support of the size‐plasticity hypothesis. Community assembly was governed primarily by stochastic processes, even though deterministic processes were also important. Turnover dominated community composition for all organismal groups. Putative functions of prokaryotes pertained mainly to carbon and nitrogen cycling. Our study provided mechanistic insights into the diversity of soil organisms across different trophic levels found in apple orchards.

Soil biota is responsible for essential biological processes occurring in the soil. Biota composition, biodiversity and activity can be affected by soil properties, biogeography and human activities. This study, conducted in vineyards of Northeast Italy, aimed to understand the combined effect of edaphic and agronomic factors on the composition and biodiversity of soil biota in four soil types characterised by different pedological origin. The soil biota was studied by simultaneously investigating the composition and the biodiversity of fungal, bacterial and microarthropod communities and their interactions with abiotic factors. The results show that the impact of natural soil characteristics and viticulture activity on biota depends on soil type. Some fungal, bacterial and microarthropod community groups were characteristic only of certain soil types. Geographical position and edaphic factors mainly affected the composition of microbial communities, while microarthropods seemed to respond less to these variables. Depending on the origin of the soil, the biodiversity of the biota responded differently to viticulture practices. The study shows that understanding how natural and agronomic factors drive soil biota makes it possible to predict the effect of natural or artificial changes on soil biological processes.

PDLIM2 is a cytoskeletal and nuclear protein present in hematopoietic and epithelial cells that regulates cell differentiation and the protein stability of transcription factors including NF-κB, STATs, and β-catenin (1). PDLIM2 expression is repressed in certain cancers, but is highly expressed in cancer cells that exhibit a metastatic phenotype (2). PDLIM2 is also highly expressed in the tumour microenvironment of breast cancer, particularly in the pro-wound healing M2 macrophage population. In line with this, bone-marrow derived macrophages from PDIM2 knockout (KO) mice have impaired differentiation towards the M2 macrophage phenotype (3). Here we investigated the effects of PDLIM2 loss in epithelial and immune cells in a colitis-associated cancer model using PDLIM2 wild type (WT) and KO mice exposed to dextran sodium sulphate (DSS) and azoxymethane (AOM). We observed that PDLIM2 KO mice exhibited a strong response to DSS alone. Colon tissue from DSS-treated mice exhibited impaired epithelium repair, sustained inflammation, and low levels of wound-healing M2 macrophages compared to WT tissues. To address the molecular mechanisms associated with PDLIM2 KO in colon epithelial cells, we suppressed or knocked out PDLIM2 in the Caco2 cell line. Caco-2 cells lacking PDLIM2 displayed dysregulated adhesion signalling, which was accompanied by elevated levels of reactive oxygen species (ROS), mitochondrial dysfunction and increased dependence on glycolysis. Overall, we conclude that PDLIM2 is required for the resolution of inflammation and to promote intestinal epithelial repair through regulating cell adhesion signalling and cellular redox balance. 1. Guo ZS, Qu Z. PDLIM2: Signaling pathways and functions in cancer suppression and host immunity. Biochim Biophys Acta Rev Cancer. 2021 Dec;1876(2):188630. doi: 10.1016/j.bbcan.2021.188630. 2. Cox OT, Edmunds SJ, Simon-Keller K, Li B, Moran B, Buckley NE, Bustamante-Garrido M, Healy N, O'Flanagan CH, Gallagher WM, Kennedy RD, Bernards R, Caldas C, Chin SF, Marx A, O'Connor R. PDLIM2 Is a Marker of Adhesion and β-Catenin Activity in Triple-Negative Breast Cancer. Cancer Res. 2019 May 15;79(10):2619-2633. doi: 10.1158/0008-5472.CAN-18-2787. 3. Cox OT, O'Sullivan N, Tresse E, Ward S, Buckley N, O'Connor R. PDLIM2 is highly expressed in Breast Cancer tumour-associated macrophages and is required for M2 macrophage polarization. Front Oncol. 2022 Nov 30;12:1028959. doi: 10.3389/fonc.2022.1028959. Citation Format: Stephanie Ward, Silvia Melgar, Orla T Cox, Raffaella Morelli, Rosemary O'Connor. PDLIM2 is required for regulating inflammation and cellular redox levels in mouse colorectal epithelial model [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A154.

The high demand for wine in Europe has increased the impact of viticulture on the environment. In line with European objectives, more sustainable agronomic practices have spread as an alternative to traditional management. This study aimed to compare, in a vineyard of Pinot blanc and Rhine Riesling in northeast Italy, the integrated agronomic practices (INT) with two types of organic management (ORG1—cattle manure and ORG2—green manure), in terms of production, grape quality, pest susceptibility, and soil nutrient availability. The results, after the fifth, sixth, and seventh year of testing, showed that organic management obtained a yield and vegetative features comparable to INT. Grape quality also did not show considerable overall differences between the theses in the must properties, despite the higher total sugar content and lower yeast available in ORG1. In the three-year period, the management of downy mildew, powdery mildew, and rot, as well as the soil fertilization, with the products available in organic farming proved to be comparable to the INT method. The application of cattle manure contributed by enriching the soil in K and P, while a balanced green manure mix has proven to be the best agronomic practice in terms of the release of mineral N during the phenological stages of greatest need of the vine. Organic management appears as an agronomic strategy able quantitatively and qualitatively support the vineyard system.

The intensive exploitation of agricultural land has caused a depletion of soil organic carbon (SOC) and a decline in soil fertility, with a consequent decrease in the productivity of agroecosystems, also contributing to atmospheric GHG emissions. The ability of soil to storage organic carbon (OC) depends on its persistence and susceptibility to decomposition. SOC is generally partitioned into fractions differing in protection mechanisms and in turn decomposability. This study aimed to compare the OC pool repartition in soils managed with three different fertilization practices (mineral – CONV, manure – ORGM and green manure – ORG-GM) during a medium-term trial in vineyard, in order to understand the best solution in increasing C sequestration. The OC fractionation by acid hydrolysis allowed separating three fractions of OC: a labile, quickly mineralizable pool, a recalcitrant pool with a slower turnover and a stable pool protected by microbial attack. The results showed that the periodic application of organic matrices (manure and green manure), although did not increase total OC, enriched the soil along time with readily available OC, thus promoting the release of nutrients. Green manure has also been shown to promote the accumulation of stabilized OC, able to improve the structure of the soil and, therefore, its fertility.

The use of conservation and sustainable practices could restore the abundance and richness of soil organisms in agroecosystems. Fitting in this context, this study aimed to highlight whether and how different soil living communities reacted to the conversion from an integrated to an organic orchard. The metataxonomic approach for fungi and bacteria and the determination of biological forms of diatoms and microarthropods were applied. Soil analyses were carried out in order to evaluate the effect of soil chemical features on four major soil living communities. Our results showed that the different taxa reacted with different speeds to the management changes. Fungi responded quickly to the changes, suggesting that modification in agricultural practices had a greater impact on fungal communities. Bacteria and microarthropods were more affected by abiotic parameters and less by the management. The diatom composition seemed to be affected by seasonality but the highest H’ (Shannon index) value was measured in the organic system. Fungi, but also diatoms, seemed to be promising for monitoring changes in the soil since they were sensitive to both the soil features and the anthropic impact. Our study showed that soil biodiversity could be affected by the conversion to sustainable management practices from the early years of an orchard onwards. Therefore, better ecological orchard management may strengthen soil sustainability and resilience in historically agricultural regions.