Stilbenes are a small family of polyphenolic secondary metabolites that can be found in several distantly related plant species. These compounds act as phytoalexins, playing a crucial role in plant defense against phytopathogens, as well as being involved in the adaptation of plants to abiotic environmental factors. Among stilbenes, trans-resveratrol is certainly the most popular and extensively studied for its health properties. In recent years, an increasing number of stilbene compounds were subjected to investigations concerning their bioactivity. This review presents the most updated knowledge of the stilbene biosynthetic pathway, also focusing on the role of several environmental factors in eliciting stilbenes biosynthesis. The effects of ultraviolet radiation, visible light, ultrasonication, mechanical stress, salt stress, drought, temperature, ozone, and biotic stress are reviewed in the context of enhancing stilbene biosynthesis, both in planta and in plant cell and organ cultures. This knowledge may shed some light on stilbene biological roles and represents a useful tool to increase the accumulation of these valuable compounds.

No abstract

Summer drought represents one of the main stress sources stress for plant communities in the Mediterranean region. Plants can adopt several response strategies to cope with stress, reflected in the adoption of specific Plant Functional Traits (PFTs). Trait-based approaches commonly meet three critical issues: they overlook Intraspecific Variability (ITV), they focus on a large spatial scale, or they focus on single trait responses to stress. In this study, we present evidence for a significant amount of ITV in morphological and anatomical trait syndromes observed between three local populations of Phyllirea latifolia, Pistacia lentiscus and Quercus ilex, distributed along an aridity gradient. Thicker, more physiologically expensive leaves and lower heights found in the drier sites mainly conform to drought-resistance strategies. Interestingly, PFTs from Cistus salviifolius were found not to vary between sites. This implies that not all species vary at the same geographical scale, possibly depending on their different successional role. The main implication behind our findings is that climate can easily drive significant ITV in multiple traits among plant populations, even at a local scale, although trait responsiveness might be species-specific. Different plant populations hailing from the same geographical regions might thus respond differently to climate change.

Cultivated rice is a staple food for more than half of the world’s population, providing approximately 20% of the world’s food energy needs. A broad spectrum of pathogenic microorganisms causes rice diseases leading to huge yield losses worldwide. Wild and cultivated rice species are known to possess a wide variety of antimicrobial secondary metabolites, known as phytoalexins, which are part of their active defense mechanisms. These compounds are biosynthesized transiently by rice in response to pathogens and certain abiotic stresses. Rice phytoalexins have been intensively studied for over half a century, both for their biological role and their potential application in agronomic and pharmaceutical fields. In recent decades, the growing interest of the research community, combined with advances in chemical, biological, and biomolecular investigation methods, has led to a notable acceleration in the growth of knowledge on rice phytoalexins. This review provides an overview of the knowledge gained in recent decades on the diversity, distribution, biosynthesis, chemical synthesis, and bioactivity of rice phytoalexins, with particular attention to the most recent advances in this research field.

Local homogeneity is a common assumption in ecology, which can lead to the aggregation of populations without regard for their unique needs and characteristics. Here we discuss whether this assumption is justified, and we hypothesize an approach to formulate an informed decision, by discerning the source of variation between plasticity and adaptation. We test this approach on plants, performing a common garden experiment to guide our choice discerning between the two at a local scale (~60 Km). Using functional trait measurements for three species, Quercus ilex, Pistacia lentiscus and Cistus salviifolius, hailing from three sites chosen along a local aridity gradient, we were able to reject the local homogeneity assumption for Q. ilex and C. salviifolius at this scale due to the adaptive divergence observed among neighbouring populations. We conclude that gathering empirical evidence can provide with solid bases to decide whether to adopt the local homogeneity assumption.