Abstract
Photosensitivity in animals is defined as a severe dermatitis that results from a heightened reactivity of skin cells and associated dermal tissues upon their exposure to sunlight, following ingestion or contact with UV reactive secondary plant products. Photosensitivity occurs in animal cells as a reaction that is mediated by a light absorbing molecule, specifically in this case a plant-produced metabolite that is heterocyclic or polyphenolic. In sensitive animals, this reaction is most severe in non-pigmented skin which has the least protection from UV or visible light exposure. Photosensitization in a biological system such as the epidermis is an oxidative or other chemical change in a molecule in response to light-induced excitation of endogenous or exogenously-delivered molecules within the tissue. Photo-oxidation can also occur in the plant itself, resulting in the generation of reactive oxygen species, free radical damage and eventual DNA degradation. Similar cellular changes occur in affected herbivores and are associated with an accumulation of photodynamic molecules in the affected dermal tissues or circulatory system of the herbivore. Recent advances in our ability to identify and detect secondary products at trace levels in the plant and surrounding environment, or in organisms that ingest plants, have provided additional evidence for the role of secondary metabolites in photosensitization of grazing herbivores. This review outlines the role of unique secondary products produced by higher plants in the animal photosensitization process, describes their chemistry and localization in the plant as well as impacts of the environment upon their production, discusses their direct and indirect effects on associated animal systems and presents several examples of well-characterized plant photosensitization in animal systems.
Highlights
Bioactive Secondary Products Produced by Plants—Their Role in Plant DefensePlants and their associated microflora produce a vast assortment of natural products in their respective metabolomes
We present recent research approaches used to investigate photosensitization associated with a recently introduced summer annual pasture legume in Australia, biserrula (Biserrula pelecinus L.) (Papilionoideae) in which the active constituent causing photosensitization is unknown
The impacts of photosensitizing secondary plant products (SPPs) can lead to sporadic and/or significant breakouts of photosensitization in grazing herbivores, with some leading to considerable economic losses for livestock producers
Summary
Plants and their associated microflora produce a vast assortment of natural products in their respective metabolomes. Many natural products do not appear to participate directly in plant growth and development, and in some cases their roles are not well understood These compounds are referred to as secondary plant products (SPPs) and certain families of plants exhibit great metabolic specificity in the SPPs they produce. A smaller subset of SPPs is associated with interactions between plants and their herbivores, which include grazing animals as well as insects and arthropods. Some of these compounds are critically important in the attraction and deterrence of herbivores, one form of chemical communication or signaling [4,7,11]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
