Juglans regia L. is a crucial species as a forest tree and for its nutritional and medicinal values. It is also included in the list of endangered species in Albania and thus, there is a need to find methodologies to ensure its rapid regeneration and ex situ conservation. This research, investigated the regeneration of plantlets from synthetic seeds containing shoot tips of four native walnut varieties: ‘Përmet’, ‘Korçë’, ‘Peshkopi’, and ‘Tropojë’. First, in vitro-derived shoot tips from walnut seedlings are encapsulated using sodium alginate. After that, the regeneration potential of the encapsulated shoot tips and the influence of incubation conditions are evaluated. The synthetic seeds were incubated at either 25 °C or 8 °C, with and without dehydration treatment, in 0.5 M sucrose solution for 3 h. The synthetic seeds in both temperature regimes (25 °C and 8 °C) develop plantlets and provid conservation potential without the need for subcultures for 4 and 3.5 months, respectively. Furthermore, all walnut varieties incubated in these conditions achiev a high regeneration rates.

Although nanotechnology is increasingly applied in plant tissue culture in many parts of Europe, its use in the Balkans remains limited, revealing a regional gap with untapped potential for advancing in vitro propagation and preservation of woody plant species. Building upon a recently published regional review covering 2001–2024, which analyzed in vitro biotechnology progress in nine Balkan countries, this paper introduces the concept of a “nano gap”, referring to the limited connection between existing nanotechnology research potential and its use in in vitro woody plant biotechnology. In Serbia, Greece, Bulgaria, Croatia, and Albania, significant progress has been made in optimizing micropropagation and in vitro conservation strategies by introducing temporary immersion systems, synthetic seed technology, adapting genotype-specific sterilization and multiplication protocols, and modifying established cryopreservation methods for regional woody species. However, the integration of nanotechnology into these systems remains largely unexplored. To date, there are no published results or validated applications for nano-enhanced media or nanoscale delivery systems for micropropagation and in vitro conservation of woody species. The limited integration of nanotechnology may be due to insufficient funding, lack of specialized infrastructure, and limited interdisciplinary expertise. Nevertheless, many Balkan countries possess growing capacities in nano-applications within agriculture and environmental sciences and are ready to advance toward interdisciplinary research and innovation. By mapping both scientific readiness and structural barriers, this review provides a strategic framework for bridging the “nano gap” and offers a novel regional perspective with broader implications for European research policy, sustainable agriculture, biodiversity preservation, and green innovation.

The stone fruit industry, particularly plum (Prunus domestica) production, is important to the Albanian economy. The Prunus domestica ‘Tropojane’ predominates due to its high and stable productivity, adaptability, and superior organoleptic qualities. Assessing phytosanitary status of this fruit plant is important, to ensure sustainable production and preserve genetic resources. During the spring seasons of 2022, 2023 and 2024, 129 samples of ‘Tropojane’ plum were collected across the regions of Tropoja, Kukës, Has, Puka, Durrës, Paskuqan, and Kamëz of Albania. All samples were tested by ELISA, PCR, and qPCR to detect plum pox virus (PPV), the most destructive virus infecting plum, and to screen for additional stone fruit viruses including Prunus necrotic ringspot virus (PNRSV), prune dwarf virus (PDV), apple mosaic virus (ApMV), and apple chlorotic leafspot virus (ACLSV). ELISA tests demonstrated that PPV was present in 35.5% of the samples, whereas RT-PCR and RT-qPCR assays detected PPV in 45.6% of the samples, confirming greater sensitivity of the PCR assays for virus detection. No infections with other assessed stone fruit viruses were detected. PPV identity was confirmed by sequencing, and phylogenetic analyses showed that the Albanian isolates clustered within the Rec strain group, also indicating their possible regional origin. Meristem culture was employed as a sanitation strategy for PPV-infected explants. Differences in regeneration capacity among plum populations were observed, yet stable in vitro cultures were established in all cases, and molecular diagnostics confirmed that regenerated plantlets were PPV-free. In vitro shoots were successfully subcultured, rooted, and acclimatized. These results highlight the need to conserve native plum germplasm, and enforce the use of certified planting material, to ensure the long-term preservation of autochthonous cultivars, while preventing further spread of PPV.