Ecological Genomics of Plant-Insect Interactions: The Case of Wasp-Induced Galls

Plant-insect interactions are central to understand ecological and evolutionary dynamics that shaped phenotypes and genotypes. Although the interaction between host plants and insect herbivores has been widely assessed, the molecular mechanisms behind it are largely unknown. Here, we discuss the significance of the ecological genomics for the study of nonmodel species in the context of specialized herbivore interactions. First, we provide an overview of ecological genomics and review functional genomic studies addressing plant responses to herbivores. Second, using the oak-wasp interaction as a framework, we addressed the molecular mechanisms involved in the response of host plants to specialized phytophagous insects. We present a functional study of gene expression along the development of oak galls induced by cynipid insects. The transcriptomic profiles depicted show changes in gene regulation related to metabolism and cell cycle, which are consistent with the developmental trajectory of growing larvae. These findings suggest phenotype manipulation of the host plant by the wasp larvae and support the adaptive role of galls as a life history trait of insects. Our study provides insight of how the ecological genomics approach can contribute to elucidate the genetic bases of organism’s response to their environment and thus help to better understand species interactions and adaptation. In order to unravel the genetic control of natural variation, we suggest that future research should encompass applied ecology and evolution, molecular biology, and bioinformatic and genomic tools.