Exoskeleton formation in Apis mellifera: Cuticular hydrocarbons profiles and expression of desaturase and elongase genes during pupal and adult development

Author(s)

Falcon, Tiago ^[1] ; Ferreira-Caliman, Maria Juliana ^[2] ; Franco Nunes, Francis Morais ^[3] ; Tanaka, Erica Donato ^[1] ; do Nascimento, Fabio Santos ^[2] ; Gentile Bitondi, Marcia Maria ^[2]

Affiliation

^[1] Univ Sao Paulo, Fac Med Ribeirao Preto, BR-14049900 Ribeirao Preto, SP - Brazil

^[2] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, BR-14040901 Ribeirao Preto, SP - Brazil

^[3] Univ Fed Sao Carlos, Ctr Ciencias Biol & Saude, BR-13565905 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: Insect Biochemistry and Molecular Biology; v. 50, p. 68-81, JUL 2014.
• Web of Science Citations: 21

Abstract

Cuticular hydrocarbons (CHCs) are abundant in the superficial cuticular layer (envelope) of insects where they play roles as structural, anti-desiccation and semiochemical compounds. Many studies have investigated the CHC composition in the adult insects. However, studies on the profiles of these compounds during cuticle formation and differentiation are scarce and restrict to specific stages of a few insect species. We characterized the CHCs developmental profiles in the honeybee workers during an entire molting cycle (from pupal-to-adult ecdyses) and in mature adults (forager bees). Gas chromatography/mass spectrometry (GC/MS) analysis revealed remarkable differences in the relative quantities of CHCs, thus discriminating pupae, developing and newly-ecdysed adults, and foragers from each other. In parallel, the honeybee genome database was searched for predicted gene models using known amino acid sequences of insect enzymes catalyzing lipid desaturation (desaturases) or elongation (elongases) as queries in BLASTP analysis. The expression levels of six desaturase genes and ten elongase genes potentially involved in CHC biosynthesis were determined by reverse transcription and real time polymerase chain reaction (RT-qPCR) in the developing integument (cuticle and subjacent epidermis). Aiming to predict roles for these genes in CHC biosynthesis, the developmental profiles of CHCs and desaturase/elongase transcript levels were evaluated using Spearman correlation coefficient. This analysis pointed to differential roles for these gene products in the biosynthesis of certain CHC classes. Based on the assumption that homologous proteins may share a similar function, phylogenetic trees were reconstructed as an additional strategy to predict functions and evolutionary relationships of the honeybee desaturases and elongases. Together, these approaches highlighted the molecular complexity underlying the formation of the lesser known layer of the cuticular exoskeleton, the envelope. (c) 2014 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 10/16380-9 - Molecular genetics and hormonal regulation of exoskeleton differentiation in an insect model, Apis mellifera
• Grantee: Marcia Maria Gentile Bitondi
• Support Opportunities: Regular Research Grants
• FAPESP's process: 11/03171-5 - Causal analysis of Apis mellifera development: regulatory genes and hierachical networks of gene expression in the specification of tissue and organs
• Grantee: Zilá Luz Paulino Simões
• Support Opportunities: Research Projects - Thematic Grants