Environmental extremes, such as drought and flooding, are becoming increasingly common, resulting in significant crop losses. The aim of the present study was to understand the molecular response induced by drought and waterlogging conditions, and to link these responses to the physiological adaptation of plants. For this purpose, leaf RNA expression was analyzed in potted kiwifruit plants by Illumina Next Generation Sequences. Stressed plants showed an impairment of all physiological parameters (leaf-gas exchange and stem-water potential) with a more evident effect in waterlogging condition than in drought condition. However, the impact on the transcriptome in waterlogged plants was less intense than in drought stress. Drought affected several metabolic pathways, among which “plant hormone signal transduction”, “protein processing in endoplasmic reticulum”, and “mitogen-activated protein kinase signaling pathway” were the most representative in terms of number of genes involved. The genes involved in the biosynthesis of phenylpropanoids were positively influenced by both drought and waterlogging. Finally, waterlogging stimulated secondary metabolisms by upregulating the genes responsible for the biosynthesis of terpenoids and flavonoids, such as stilbenoids. The obtained results show that the two contrasting stress conditions share several common physiological responses and molecular mechanisms.

The intensification of agricultural practices and the consequent dramatic decrease in soil organic matter has increased the use of organic fertilizer to recover soil fertility and plant productivity. The aim of this study was to compare the effect of three amendments obtained from the recycling of urban and agri-food wastes on rhizosphere microbial community, soil, and plant nutrient status. The experiment was carried out on rhizobox-grown, 1-year-old vines of Sangiovese (Vitis vinifera L.), grafted onto 110 Richter (V. berlandieri × V. rupestris) planted in April 2023. Twenty-four rhizoboxes were filled with soil collected from a field trial in which three types of amendments had been applied since 2019. In detail, the complete randomized experimental design (with four replications) compared the following treatments: (1) municipal organic waste compost (ACM), (2) agri-food organic waste compost (ACF), (3) defecation gypsum (GDD), and (4) a control that received 60 kg of N ha⁻¹ year⁻¹ (CK). The application of the amendments increased the soil concentration of total C, total N, and pH. The application of ACM increases soil K and Zn and the concentration of N and K in plant roots. The application of all the amendments increased leaf N concentration in comparison with CK, but only ACF increased leaf P. ACM was the most effective in promoting microbial biodiversity, increasing phyla like Bacillota, Pseudomonata, and Bacteroidota, including genra like Bacillus, Neobacillus, Paenibacillus, and Pseudomonas. ACF promoted Nitrosospherota and Chitinophaga, and GDD promoted Chloroflexota and Agrobacterium.