Plant-Herbivore Interactions: Insights from Chemical Ecology and Chemodiversity

Dear Colleagues,

Chemically mediated interactions between plants and herbivores are known as key drivers of ecological and evolutionary processes in terrestrial, marine, and freshwater ecosystems. Herbivores, faced with resources with different nutritional characteristics and palatability, have developed several adaptations that drive plants concomitantly, and consequently, to produce secondary metabolites (SMs), with different patterns of diversification (chemodiversity), forming the basis for chemical ecology. The specific mechanisms through which trophic relations contribute to the diversification of SMs, and ultimately to the maintenance of biodiversity in the environment, as well as their role in structuring biological communities are still to be explored. Despite the knowledge accumulated in decades of study, there are still many gaps that need to be filled, involving, for example, previous and current plant–herbivore interactions at the population level and the observed patterns of conserved SMs (constitutive) versus activated or induced ones.  Further, there is a need to broaden the one-sided focus to different specific life stages at different organizational levels for the entire developmental process and their respective assessments of chemical responses to biological drivers such as herbivory. At the ontogenetic level, there are few analyses of the production of herbivore effectors and the expression of plant defense genes that can considerably expand the range of reproduction targets.

In this Special Issue, original articles, methods, opinions, perspectives, hypotheses, modeling, and reviews exploring these approaches in marine, freshwater, and terrestrial environments will be very welcome. The themes can also be varied, involving aspects such as metabolism, metabolomic, effects of biotic and abiotic factors on chemical mediation, and chemical mediation as a structuring element at different levels of organization.

We are excited to create this Special Issue that covers plant–herbivore chemical interaction in aquatic and terrestrial environments at different scales of chemodiversity in the journal Plants. This Special Edition aims to collect high-quality manuscripts on different aspects involving chemically mediated plant–herbivore interactions.

Prof. Dr. Renato Crespo Pereira
Prof. Dr. Davyson de Lima Moreira
Dr. Bernardo Antonio Perez Da Gama
Guest Editors

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• chemical ecology
• chemical mediation
• phenotypic chemical diversity
• plant defense traits
• evolution of chemical defense
• chemodiversity
• chemically mediated interactions
• herbivory

Title: Structural and histochemical traits of two Microgramma species (Polypodiaceae): secretory structures and their potential implications of herbivory levels
Authors: Ranielle de Araújo Mendonça; Rafael de Paiva Farias; Ana Carla Feio
Affiliation: 1 Universidade Federal Rural da Amazônia, Programa de Pós-Graduação em Ciências Biológicas – Botânica Tropical. Av. Perimetral, 1901 - Terra Firme, 66077530, Belém, Pará, Brasil 2 Universidade Federal da Bahia, Instituto de Biologia. R. Barão de Jeremoabo, 668 – Ondina, 40170115, Salvador, Bahia, Brasil 3 Programa de Pós-graduação em Ciências Biológicas/Botânica, Universidade Federal do Rio de Janeiro/Museu Nacional, Parque Quinta da Boa Vista1, 20940-040, Rio de Janeiro, RJ, Brazil
Abstract: There is poor advice in the literature on the anatomy, histochemistry and roles of secretory structures in ferns. This study presents the anatomical and histochemical characterization of Microgramma reptans and M. lycopodioides, with emphasis on secretory structures and traits related to herbivory. Sampling took place in the Parque Estadual do Utinga, Pará – a Conservation Unit of Amazon rainforest. Leaves were collected and fixed according to protocols for anatomical analysis with light and scanning electron microscopy. Leaves were collected for the assessment of herbivory levels based on classes of area removed by herbivory. Both species had glandular trichomes on the leaf blade, dispersed in M. lycopodioides, and clustered under scales in M. reptans. In both species, trichomes had positive histochemical results for phenolic compounds, total lipids, acidic mucilages, alkaloids, proteins, and total polysaccharides. Hydathodes were recorded for the first time in M. reptans, with an unusual composition. Leaf herbivory was low in both species and significantly higher in M. lycopodioides (0.38%) than in M. reptans (0.08%). The association formed by scales and glandular trichomes, and the presence of the set of heterogeneous compounds in the hydathodes of M. reptans can help better protect against herbivores.