Significance: Plants detect conserved molecular patterns of pathogens via cell surface-localized receptors, such as the flagellin receptor kinase FLS2, that initiate effective plant immunity. Activated FLS2 is endocytosed, but the degree to which other receptor kinases exhibit similar spatiotemporal dynamics remains unclear. We show that internalization into a common endosomal pathway after ligand perception is a general phenomenon of the tested receptor kinases, including the danger peptide receptor PEPR1. FLS2 endocytosis is mediated by clathrin and is uncoupled from the regulation of acute pathogen-induced responses, but is involved in steady defenses and contributes to plant immunity against bacterial infection. We propose that clathrin-dependent internalization of ligand-activated receptor kinases into a common endosomal pathway facilitates the responses required for full plant immunity.

The medicinal potential of hop (Humulus lupulus L.) is widely cited in ancient literature and is also allowed in several official pharmacopoeias for the treatment of a variety of ailments, mainly related to anxiety states. This is due to the plethora of phytoconstituents (e.g., bitter acids, polyphenols, prenyl flavonoids) present in the female inflorescences, commonly known as cones or strobili, endowed with anti-inflammatory, antioxidant, antimicrobial, and phytoestrogen activities. Hop has recently attracted the interest of the scientific community due to the presence of xanthohumol, whose strong anti-cancer activity against various types of cancer cells has been well documented, and for the presence of 8-prenyl naringenin, the most potent known phytoestrogen. Studies in the literature have also shown that hop compounds can hinder numerous signalling pathways, including ERK1/2 phosphorylation, regulation of AP-1 activity, PI3K-Akt, and nuclear factor NF-κB, which are the main targets of the antiproliferative action of bitter acids and prenylflavonoids. In light of these considerations, the aim of this review was to provide an up-to-date overview of the main biologically active compounds found in hops, as well as their in vitro and in vivo applications for human health and disease prevention. To this end, a quantitative literature analysis approach was used, using VOSviewer software to extract and process Scopus bibliometric data. In addition, data on the pharmacokinetics of bioactive hop compounds and clinical studies in the literature were analysed. To make the information more complete, studies on the beneficial properties of the other two species belonging to the genus Humulus, H. japonicus and H. yunnanensis, were also reviewed for the first time.

In recent years, there has been growing interest in bioactive plant compounds for their beneficial effects on health and for their potential in reducing the risk of developing certain diseases such as cancer, cardiovascular diseases, and neurodegenerative disorders. The extraction techniques conventionally used to obtain these phytocompounds, however, due to the use of toxic solvents and high temperatures, tend to be supplanted by innovative and unconventional techniques, in line with the demand for environmental and economic sustainability of new chemical processes. Among non-thermal technologies, cold plasma (CP), which has been successfully used for some years in the food industry as a treatment to improve food shelf life, seems to be one of the most promising solutions in green extraction processes. CP is characterized by its low environmental impact, low cost, and better extraction yield of phytochemicals, saving time, energy, and solvents compared with other classical extraction processes. In light of these considerations, this review aims to provide an overview of the potential and critical issues related to the use of CP in the extraction of phytochemicals, particularly polyphenols and essential oils. To review the current knowledge status and future insights of CP in this sector, a bibliometric study, providing quantitative information on the research activity based on the available published scientific literature, was carried out by the VOSviewer software (v. 1.6.18). Scientometric analysis has seen an increase in scientific studies over the past two years, underlining the growing interest of the scientific community in this natural substance extraction technique. The literature studies analyzed have shown that, in general, the use of CP was able to increase the yield of essential oil and polyphenols. Furthermore, the composition of the phytoextract obtained with CP would appear to be influenced by process parameters such as intensity (power and voltage), treatment time, and the working gas used. In general, the studies analyzed showed that the best yields in terms of total polyphenols and the antioxidant and antimicrobial properties of the phytoextracts were obtained using mild process conditions and nitrogen as the working gas. The use of CP as a non-conventional extraction technique is very recent, and further studies are needed to better understand the optimal process conditions to be adopted, and above all, in-depth studies are needed to better understand the mechanisms of plasma–plant matrix interaction to verify the possibility of any side reactions that could generate, in a highly oxidative environment, potentially hazardous substances, which would limit the exploitation of this technique at the industrial level.

Plants, with their range of pharmacologically active molecules, represent the most promising source for the production of new anticancer drugs and for the formulation of adjuvants in chemotherapy treatments to reduce drug content and/or counteract the side effects of chemotherapy. Casticin is a major bioactive flavonoid isolated from several plants, mainly from the Vitex species. This compound is well known for its anti-inflammatory and antioxidant properties, which are mainly exploited in traditional medicine. Recently, the antineoplastic potential of casticin has attracted the attention of the scientific community for its ability to target multiple cancer pathways. The purpose of this review is, therefore, to present and critically analyze the antineoplastic potential of casticin, highlighting the molecular pathways underlying its antitumor effects. Bibliometric data were extracted from the Scopus database using the search strings “casticin” and “cancer” and analyzed using VOSviewer software to generate network maps to visualize the results. Overall, more than 50% of the articles were published since 2018 and even more recent studies have expanded the knowledge of casticin’s antitumor activity by adding interesting new mechanisms of action as a topoisomerase IIα inhibitor, DNA methylase 1 inhibitor, and an upregulator of the onco-suppressive miR-338-3p. Casticin counteracts cancer progression through the induction of apoptosis, cell cycle arrest, and metastasis arrest, acting on several pathways that are generally dysregulated in different types of cancer. In addition, they highlight that casticin can be considered as a promising epigenetic drug candidate to target not only cancer cells but also cancer stem-like cells.

Bacterial spot caused by Xanthomonas arboricola pv. pruni (Xap) is a major threat to Prunus species worldwide. The molecular mechanisms of peach resistance to Xap during early leaf infection were investigated by RNA-Seq analysis of two Prunus persica cultivars, ‘Redkist’ (resistant), and ‘JH Hale’ (susceptible) at 30 minutes, 1 and 3 hours-post-infection (hpi). Both cultivars exhibited extensive modulation of gene expression at 30 mpi, which reduced significantly at 1 hpi, increasing again at 3 hpi. Overall, 714 differentially expressed genes (DEGs) were detected in ‘Redkist’ (12% at 30 mpi and 1 hpi and 88% at 3 hpi). In ‘JH Hale’, 821 DEGs were identified (47% at 30 mpi and 1 hpi and 53% at 3 hpi). Highly up-regulated genes (fold change > 100) at 3 hpi exhibited higher fold change values in ‘Redkist’ than in ‘JH Hale’. RNA-Seq bioinformatics analyses were validated by RT-qPCR. In both cultivars, DEGs included genes with putative roles in perception, signal transduction, secondary metabolism, and transcription regulation, and there were defense responses in both cultivars, with enrichment for the gene ontology terms, ‘immune system process’, ‘defense response’, and ‘cell death’. There were particular differences between the cultivars in the intensity and kinetics of modulation of expression of genes with putative roles in transcriptional activity, secondary metabolism, photosynthesis, and receptor and signaling processes. Analysis of differential exon usage (DEU) revealed that both cultivars initiated remodeling their transcriptomes at 30 mpi; however, ‘Redkist’ exhibited alternative exon usage for a greater number of genes at every time point compared with ‘JH Hale’. Candidate resistance genes (WRKY-like, CRK-like, Copper amine oxidase-like, and TIR-NBS-LRR-like) are of interest for further functional characterization with the aim of elucidating their role in Prunus spp. resistance to Xap.