Speakers - Marcelo Lorenzo

Type of the Presentation: (Short lecture)




Jose Manuel Latorre-Estivalis1, Ewald Grosse-Wilde2, Sheila Ons1, Alessandra Guarneri3, Marcelo Lorenzo3


1  CREG-Univ. La Plata, La Plata, Argentina

2  Max Planck Institute for Chemical Ecology, Jena, Germany

2  CPqRR-FIOCRUZ, Belo Horizonte, Brazil

*  Correspondence: marcelo@cpqrr.ficruz.br


The genome sequence of Rhodnius prolixus, an important vector of Chagas disease, has been published. These insects present state-dependency in their responsiveness to hosts after molting to each stage. NGS facilitates uncovering the molecular bases of sensory processes. We aimed at mass sequencing transcripts produced during the first week after molting in the antennae of 5th instar larvae. We focused on changes in relative expression presented by selected target genes as a proxy for maturation of the main sensory organs through this time interval. Thirty-five RNA samples (five age points, 7 replicate samples per age) of antennae of 5th instar larvae (20 per sample) were prepared into RNAseq libraries using Illumina's TruSeq Stranded RNA Sample Prep kit. Age points chosen (0, 2, 4, 6 and 8 days) represent the interval in which responsiveness to hosts settles-in (i.e., maturation) in these bugs. Libraries were mass sequenced using paired-end reads (Illumina HiSeq technology), while the coverage of each library had at least 15 million reads.

Expression data suggest that antennae of 5th instar larvae experience a maturation process in which almost a third of the genes expressed (17.000 expressed in total) had their expression profiles altered. Genes for which expression showed significant changes included those of odorant and ionotropic receptors, of candidate thermoreceptors, as well as neuropeptide, GPCR, odorant binding protein and clock genes. Our results seem to establish the molecular bases of maturation for antennal function (e.g., chemical and thermal detection) both for receptor, as well as for regulatory genes. Functional studies should be performed to understand if transcript abundance fluctuations affect physiological processes and how. We propose that the maturation in responsiveness to host odors and thermal cues known for these vector insects depends, at least in part, on the fluctuations in gene expression reported here.