Comparative analysis of the cis-regulatory network of the ovary development in queens of honey bees and stingless bees

• Grant number: 22/15906-4
• Support Opportunities: Scholarships in Brazil - Master
• Start date: March 01, 2023
• End date: February 28, 2025
• Field of knowledge: Biological Sciences - Genetics - Animal Genetics
• Principal Investigator: Flávia Cristina de Paula Freitas
• Grantee: Izabella Cristina Silva
• Host Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated research grant: 20/13719-7 - Genomic signatures of plasticity and diversity in the phenotypic development, AP.JP

Abstract

In the evolutionary history of bees that belong to Apidae family, the transition from a primitive to an advanced social organization probably occurred in two independent events, one in the honey bee group (Apini) and another in the stingless bee group (Meliponini). In both groups, eusociality is characterized by cooperative care of offspring, overlapping generations and division of labor among the reproductive individual, the queen, and the non-reproductive individuals, the workers. The division of labor is accompanied by morphological differences in organs and structures such as ovaries, brain, appendages and body size of queens and workers. These morphological differences rise as a result of the modulation of genetic programs and developmental pathways triggered by differential feeding. In bees of the species Apis mellifera, the female larvae nourished with of royal jelly, sugar, and pollen (worker jelly) give rise to workers; the larvae fed with greater amounts of royal jelly and sugar give rise to queens. In stingless bees of the genus Frieseomelitta, castes are determined based on the amount of food, so that larvae destined to become queens are nourished a greater amount of food than larvae destined to be workers. Therefore, there is a subtle difference in the stimulus that triggers caste determination in honey bees and stingless bees. In honey bees, the caste development program is triggered by the type (royal jelly or worker jelly) and by the amount of food (greater volume of food for queens). In stingless bees, the amount of the same type of food seems to be enough to trigger the development of one or another caste.Differential feeding in A. mellifera results in marked physiological changes between workers and queens, such as variations in hormone levels, in the pattern of expression of developmental and physiometabolic genes, and in the patterns of chromatin modifications and DNA methylation. Between the genes regulated by differential nutrition are those that are involved in important signaling pathways such as the Insulin/Insulin Growth Factor (IIS) and Target of rapamycin (TOR) pathway that connect the feeding signal to differential gene expression in workers and queens. However, how the regulation of the IIS and TOR pathways control caste differentiation is still unknown.A genome-wide comparative study of ten bee species, including solitary, primitively social, and eusocial bees, suggested that the transition from solitary to social living involved increased regulatory flexibility of ancestral gene networks to create reproductive and non-reproductive individuals and by the increase in the regulatory capacity of transcription factors in eusocial bee species compared to solitary species. In this context, this project will use a computational approach to compare the cis-regulatory network of ovary formation in queens of A. mellifera and F. varia. This comparison will reveal if the developmental programs of reproductive caste determination are conserved in these two species that had origins independent of eusociality, which would suggest that these mechanisms would already be present in primitively social ancestral species. For this, mRNA libraries will be constructed and sequenced from samples from ovaries collected in the larval, pupal and adult stages of queens of A. mellifera and F. varia. Comparative analysis of the transcriptome will identify conserved and species-specific gene expression profiles that may explain the differences in the queen determination process in these species. In addition, the co-regulated genes will be subjected to an analysis to identify regulatory elements for transcription factors in order to recreate the cis-regulatory network of ovarian development in each species.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

MARTINS, JULIANA RAMOS; SILVA, IZABELLA CRISTINA; MAZZONI, TALITA SARAH; DE BARRIOS, GABRIELA HELENA; FREITAS, FLAVIA CRISTINA DE PAULA; BARCHUK, ANGEL ROBERTO. Minibrain plays a role in the adult brain development of honeybee (Apis mellifera) workers. Insect Molecular Biology, v. N/A, p. 14-pg., 2024-08-21. (22/15906-4, 22/05232-6)