Organisms face constant environmental challenges, particularly in the face of rapid global change. To survive and thrive, they have evolved mechanisms that enable phenotypic plasticity—the ability to adjust their morphology, behavior, or physiology in response to changing conditions. One of the most striking examples of this adaptation is nutritional polyphenism, where a single organism produces distinct morphs, each specialized to exploit different food sources or ecological niches. This remarkable strategy allows species to anticipate resource degradation by switching to higher-quality food, ensuring their survival and reproductive success.
Despite its ecological and evolutionary significance, the mechanisms driving nutritional polyphenism remain poorly understood. Key questions persist: How do organisms detect environmental cues that trigger these phenotypic changes? What molecular and genetic pathways enable the induction and determination of alternative phenotypes? And how did this ability evolve? Moreover, recent discoveries suggest that symbiotic microorganisms, which often live in close association with their hosts, may play an overlooked but critical role in these processes.
The ALTEREVO project focuses on aphids, which are not only significant agricultural pests but also fascinating models for studying nutritional polyphenism. While many aphid species remain on the same host plant throughout their life cycle, others switch between distinct host plants—typically a woody plant for sexual reproduction and herbaceous plants for clonal reproduction—producing specialized morphs suited to the nutritional and ecological demands of each environment. This life cycle, characterized by an obligatory host alternation linked to seasonal changes, offers an ideal system for exploring the interplay between environmental triggers, molecular regulation, and evolutionary history.
ALTEREVO aims to unravel the evolutionary and molecular determinants of nutritional polyphenism in aphids by addressing the following objectives. First, the project aims to identify the specific plant compounds that act as environmental triggers, prompting aphids to develop morphs specialized for particular hosts. Next, it investigates the molecular pathways that control this polyphenism, focusing on receptors and signaling mechanisms that translate these environmental cues into phenotypic changes. Another objective is to explore the role of the aphid obligatory symbiont, Buchnera aphidicola, in regulating and possibly evolving alongside the polyphenism mechanism. Additionally, ALTEREVO examines the evolutionary origins of this trait, asking whether it arose through entirely new genetic innovations or by reconfiguring pre-existing pathways sensitive to environmental changes.
This interdisciplinary project integrates metabolomics, genomics, epigenetics, and bioinformatics to build a comprehensive understanding of nutritional polyphenism. By revealing the underlying mechanisms, ALTEREVO addresses fundamental questions about phenotypic plasticity’s role in adaptation and evolution. It also has practical implications, potentially identifying novel targets for sustainable pest management and informing strategies to mitigate agricultural damage caused by aphid crop pests.
