Pilostyles, an endoparasitic genus within the Apodanthaceae family, grows inside host stems, with flowers and fruits being the only external manifestations. Previous studies of P. berteroi growing on Adesmia trijuga provided limited details of the endophyte and omitted the origin of flowers and synker structure. This study, using classical methods of optical microscopy applied to the analysis with scanning electron microscopy and confocal laser scanning microscopy, expands the understanding of the P. berteroi/A. trijuga complex. We find that P. berteroi develops isophasically with its host, forming meristematic patches between secondary phloem cells. The parasitized Adesmia stem’s cambium primarily produces inward parenchyma cells, with limited vessel production and ceased fiber formation. The polarization of meristematic patches led to the formation of floral meristems. Flowers develop endogenously and emerge by the breakthrough of the host stem. Flowers connect to the host cambium via chimeric synkers, combining P. berteroi parenchyma and tracheoids with Adesmia vessels. Unlike previous studies that show uniformity among Pilostyles species, our analysis reveals new insights into the structural interaction between P. berteroi and A. trijuga. Further ultrastructural investigations are needed to explore potential direct or indirect connections between the vascular systems of the two taxa.

Somatic embryogenesis (SE) provides alternative methodologies for the propagation of grapevine (Vitis spp.) cultivars, conservation of its germplasm resources and for crop improvement. In this review, the current state of knowledge regarding grapevine SE as applied to these technologies is presented, with a focus on the benefits, challenges, and limitations of this method. The paper provides a comprehensive overview of the different steps involved in the grapevine SE process, including callus induction, maintenance of embryogenic cultures, and the production of plantlets. Additionally, the review explores development of high-health plant material through SE, the molecular and biochemical mechanisms underlying SE, including the regulation of gene expression, hormone signalling pathways, and metabolic pathways as well as its use in crop improvement programmes. The review concludes by highlighting the future directions for grapevine SE research, including the development of new and improved protocols, the integration of SE with other plant tissue culture techniques, and the application of SE for the production of elite grapevine cultivars, for the conservation of endangered grapevine species as well as for cultivars with unique traits that are valuable for breeding programs.

Engineered viral vectors designed to deliver genetic material to specific targets offer significant potential for disease treatment, safer vaccine development, and the creation of novel biochemical research tools. Viral tropism, the specificity of a virus for infecting a particular host, is often modified in recombinant viruses to achieve precise delivery, minimize off-target effects, enhance transduction efficiency, and improve safety. Key factors influencing tropism include surface protein interactions between the virus and host cell, the availability of host cell machinery for viral replication, and the host immune response. This review explores current strategies for modifying the tropism of recombinant viruses by altering their surface proteins. We provide an overview of recent advancements in targeting non-enveloped viruses (Adenovirus and Adeno-associated vi-rus) and enveloped viruses (Retro/Lentivirus, Rabies, Vesicular stomatitis virus, and Herpesvirus) to specific cell types. Additionally, we discuss approaches such as rational design, directed evo-lution, in silico and machine learning-based methods for generating novel AAV variants with desired tropism, and the use of chimeric envelope proteins for pseudotyping enveloped viruses. Finally, we highlight the applications of these advancements, and discuss the challenges and future directions in engineering viral tropism.