Plant trichomes are defensive specialized epidermal cells. In all accepted models, the epidermis is the layer involved in trichome formation, a process controlled by gibberellins (GAs) in Arabidopsis rosette leaves. Indeed, GA activates a genetic cascade in the epidermis for trichome initiation. Here we report that TEMPRANILLO (TEM) genes negatively control trichome initiation not only from the epidermis but also from the leaf layer underneath the epidermis, the mesophyll. Plants over-expressing or reducing TEM specifically in the mesophyll, display lower or higher trichome numbers, respectively. We surprisingly found that fluorescently labeled GA₃ accumulates exclusively in the mesophyll of leaves, but not in the epidermis, and that TEM reduces its accumulation and the expression of several newly identified GA transporters. This strongly suggests that TEM plays an essential role, not only in GA biosynthesis, but also in regulating GA distribution in the mesophyll, which in turn directs epidermal trichome formation. Moreover, we show that TEM also acts as a link between GA and cytokinin signaling in the epidermis by negatively regulating downstream genes of both trichome formation pathways. Overall, these results call for a re-evaluation of the present theories of trichome formation as they reveal mesophyll essential during epidermal trichome initiation.

The functional characterization of two Arabidopsis floral repressors unravels their role and regulation at low ambient temperatures.

Plants and plant-derived natural products have been used in traditional medicine for centuries. The lack of effective therapies in the modern world to address several diseases, the increasing development of drug resistance, and the growing interest in herbal medicine have led to the study and resurgence of natural ancient remedies. A. annua, commonly known as sweet wormwood or sweet annie, is a medicinal plant widely known for its antimalarial properties. In the past decade, increasing evidence has demonstrated the plant’s broad therapeutic potential, including antitumoral, antimicrobial, antiparasitic, metabolic, and immunomodulatory effects, among others. While most research has focused on human health, there is growing interest in exploring the veterinary applications of A. annua and its bioactive compounds, particularly artemisinin. This review aims to summarize the current knowledge on the beneficial effects of A. annua, artemisinin, and other compounds in animal health. It also highlights the need for standardizing A. annua metabolites to ensure the reliability and efficacy of treatments and explores how artemisinin works in synergy with other molecules present in A. annua.

Biostimulants represent a sustainable strategy to enhance the therapeutic potential of medicinal plants, which often exhibit low and variable levels of bioactive compounds. Cannabis sativa, a medicinally important species, produces diverse cannabinoids, such as THC, CBD, CBG, and CBC, whose profiles depend on plant chemotype and determine pharmacological activity. We developed a novel plant-based biostimulant, Tricostimulant™, to optimize cannabinoid production in Cannabis sativa. Field trials demonstrated increased biomass and selective enhancement of cannabinoid content. In high-CBD chemotypes, Tricostimulant™ was associated with higher CBD and CBG without relevant changes in THC levels, whereas in high-THC chemotypes, higher THC values were observed without evident variation in CBD. The most pronounced differences were observed when the biostimulant was applied during the vegetative stage, highlighting the importance of application timing. These results indicate the potential of Tricostimulant™ to modulate cannabinoid profiles, contributing to improved optimization and standardization of cannabis-based therapeutics. Further research is required to confirm these findings and elucidate the underlying mechanisms of biostimulant action.

Leishmaniasis is a parasitic disease caused by Leishmania spp., transmitted by sandflies, and endemic in 98 countries. Leishmania infantum, the main agent of visceral leishmaniasis in Europe, commonly infects both humans and animals, with dogs as the principal domestic reservoir. Clinical manifestations in dogs depend on the host immune response. A robust Th1 response facilitates macrophage activation and parasite control, while persistently elevated TNF-α and IL-6 can lead to chronic inflammation and tissue damage. Current treatments reduce parasite load but rarely achieve complete cure and are often associated with relapses and resistance. Artemisia annua, source of artemisinin, could be a promising alternative to canine leishmaniasis. Despite its potential, no published studies have investigated its effect specifically against Leishmania infantum as well as its possible dual action: antiparasitic and immunomodulation. We conducted in vitro evaluations of a standardized Artemisia annua extract. Leishmanicidal activity was assessed against both promastigote and amastigote stages, and cytokine modulation was evaluated in RAW 264.7 macrophages. The extract showed strong leishmanicidal activity without cytotoxicity and significantly reduced TNF-α and IL-6 levels under inflammatory conditions, and in both cases, efficiency was correlated with artemisinin content. These results support Artemisia annua as a promising safer therapeutic adjuvant candidate for canine leishmaniasis, targeting both the parasite and the host inflammatory response.

The canine gut microbiome plays a key role in digestive, immune, and metabolic health and is increasingly recognized as an important indicator of overall animal well-being. Medicinal and Aromatic Plants are emerging as a promising approach to support intestinal balance through modulation of the gut microbiome. This pilot study evaluated the effects of Aloe vera, Artemisia annua, and Curcuma longa on the gut microbiome of healthy dogs. The study included eighteen healthy dogs, divided into an Experimental group (n = 9) and a Control group (n = 9). Dogs in the Experimental group received a daily combination of the three plants for 30 days, while Control dogs received microcrystalline cellulose as a placebo. Fecal samples were collected on Day 30 and analyzed using shotgun metagenomic sequencing. Differential abundance analysis revealed an enrichment of taxa associated with short-chain fatty acid production in the Experimental group, including Megasphaera elsdenii, Blautia, Butyricimonas, Bacteroides, and Phascolarctobacterium, together with a reduction in opportunistic and dysbiosis-associated taxa, such as Enterocloster bolteae, Anaerobiospirillum spp., and Stenotrophomonas maltophilia. Functional profiling showed a reduction in pathways related to virulence-associated mechanisms and iron siderophore systems, alongside an increase in pathways associated with GABA and putrescine metabolism and serine endopeptidase activity. Overall, these findings suggest that supplementation with these functional botanical ingredients may promote a more balanced and functionally beneficial gut microbiome in healthy dogs.