Medicinal plants have been used for thousands of years in folk medicines and still are used for their health benefits. In our days medicinal plants are exploited for the isolation of plant-derived drugs as they are very effective and have relatively less or no side effects. However, the natural resources of medicinal plants are gradually exhausted and access to plant bioactive compounds is challenged by the low levels at which these products accumulate in native medicinal plants. For instance, to meet the market demands of 3 Kg per year of vinca alkaloids, powerful plant-derived anticancer drugs, 1.5×106 Kg dry leaves are required. In this regard, this review aims to highlight the fact that endophytic fungi residing in medicinal plants are capable to biosynthesize pharmacologically active secondary metabolites similar or identical to those produced by their host medicinal plant. Furthermore, the evolutionary origin of the genes involved in these metabolic pathways as well as the approaches designed to enhance the production of these metabolites by the isolated endophytic fungi are also discussed.
A. Venieraki, P.Ch. Tsalgatidou, D.G. Georgakopoulos, M. Dimou and P. Katinakis
Plant-associated environments harbor a huge number of diverse bacteria that compete and/or cooperate for the occupation of the most nutrient-rich ecological niches. Motility, a common trait among bacteria, has long been assumed to provide a survival advantage to skilful bacteria in invading these environments. Bacterial surface motility, such as swarming, a flagella-driven type of surface movement, although mostly observed and studied on agar substrates, is emerging as a major trait involved in many functions of plant-associated bacteria in regard to their ability to colonize and spread on their host. In this review, we address some novel swarming motility strategies, which enable bacteria to colonize, disperse and compete in plant surfaces.
E.-E. Thomloudi, P.C. Tsalgatidou, D. Douka, T.-N. Spantidos, M. Dimou, A. Venieraki and P. Katinakis
Plant Growth Promoting Microorganisms or Plant Probiotics (PGPMs) constitute a promising solution for agricultural sustainability. The concept that inoculation of PGPM mixtures may perform better in enhancing agricultural production than single strain application dates back to the discovery of plant growth rhizobacteria (PGPR) and is gaining ground in our days. This shift is highlighted by the increasing number of research publications dealing with the positive impact of microbial mixtures in promoting plant growth, controlling plant pathogens, as well as providing abiotic stress tolerance. The continuous deposition of patents as well as commercially available formulations concerning bioprotective and/or biostimulant multistrain mixtures also underlines this shift. A major issue in engineering an effective and consistent synthetic multistrain mixture appears to be the compatibility of its components. The present review provides a thorough literature survey supporting the view that treatment of plants with compatible multistrain mixtures generally exerts a better effect in plant growth and health than single-strain inoculation. Our study focuses on multistrain mixtures based on Pseudomonas, Bacillus and beneficial fungal strains, while commercial products are also being referred.