Genetic factors explaining anthocyanin pigmentation differences.

BACKGROUND: Anthocyanins are important contributors to coloration across a wide phylogenetic range of plants. Biological functions of anthocyanins span from reproduction to protection against biotic and abiotic stressors. Owing to a clearly visible phenotype of mutants, the anthocyanin biosynthesis and its sophisticated regulation have been studied in numerous plant species. Genes encoding the anthocyanin biosynthesis enzymes are regulated by a transcription factor complex comprising MYB, bHLH and WD40 proteins. RESULTS: A systematic comparison of anthocyanin-pigmented vs. non-pigmented varieties was performed within numerous plant species covering the taxonomic diversity of flowering plants. The literature was screened for cases in which genetic factors causing anthocyanin loss were reported. Additionally, transcriptomic data sets from four previous studies were reanalyzed to determine the genes possibly responsible for color variation based on their expression pattern. The contribution of different structural and regulatory genes to the intraspecific pigmentation differences was quantified. Differences concerning transcription factors are by far the most frequent explanation for pigmentation differences observed between two varieties of the same species. Among the transcription factors in the analyzed cases, MYB genes are significantly more prone to account for pigmentation differences compared to bHLH or WD40 genes. Among the structural genes, DFR genes are most often associated with anthocyanin loss. CONCLUSIONS: These findings support previous assumptions about the susceptibility of transcriptional regulation to evolutionary changes and its importance for the evolution of novel coloration phenotypes. Our findings underline the particular significance of MYBs and their apparent prevalent role in the specificity of the MBW complex.

Chromatic and Morphological Differentiation of Triatoma dimidiata (Hemiptera: Reduviidae) with Land Use Diversity in El Salvador.

Chagas disease is caused by the parasite Trypanosoma cruzi, which is transmitted by insect-vectors in the taxonomic subfamily Triatominae and affects approximately 8,000,000 people world-wide. Current mitigation strategies for Chagas focus on insecticides, infrastructure improvements, and management of symptoms, which are largely unsustainable in underserved communities where the disease is widespread. Transmission patterns of vector-borne diseases are known to adaptively respond to habitat change; as such, the objective of our study was to evaluate how the physical characteristics of Triatoma dimidiata would vary in relation to land use in El Salvador. We hypothesized that the color and morphology of T. dimidiata would change with municipal levels of urban and natural green space, natural green space, and agricultural space, as well as municipal diversity, richness, and evenness of land use types. Our results characterize how T. dimidiata color and morphology vary directly with anthropogenic changes to natural and agricultural environments, which are reflective of a highly adaptable population primed to respond to environmental change. Mitigation studies of Chagas disease should exploit the relationships between anthropogenic land use and T. dimidiata morphology to evaluate how the transmission pattern of T. cruzi and Chagas disease symptomology are impacted.