Banca de DEFESA: GLENDA CAROLINE CONCEIÇÃO DAMASCENO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : GLENDA CAROLINE CONCEIÇÃO DAMASCENO
DATE: 26/08/2022
TIME: 13:30
LOCAL: Recife
TITLE:

Identification and characterization of genes involved in synthesis, modification and degradation of chitin in the midgut of the three sugarcane borers

KEY WORDS:

Peritrophic membrane, chitin synthase, chitin deacetylase, chitinase, gene expression, sublethal effects

PAGES: 70
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitossanidade
SPECIALTY: Entomologia Agrícola
SUMMARY:

The peritrophic membrane (PM) is a chitin structure present in the midgut of most insects. The PM has the function of protecting the intestinal epithelium and digestion compartmentalization. MP is mainly composed of chitin and associated proteins, and this makes the enzymes involved in the metabolism of chitin in the midgut pivotal for the physiology and protection of insects. In this study, we identified and characterized the main enzymes involved in chitin metabolism, such as chitin synthase (CHS), chitin deacetylases (CDA) and chitinases (CHT), focusing on those that act in the midgut. The study targets were the sugarcane pest species, Diatraea saccharalis, Diatraea impersonatella and Telchin licus. After genes identification, the expression response of these genes was investigated in D. saccharalis under treatment with sublethal concentrations of the insecticides lufenuron, an inhibitor of chitin synthesis, and Bacillus thuringiensis (Bt), a bacterium that produces toxins that will act in the insect's midgut epithelium. The genes were identified from midgut transcriptomes of the three species studied. After protein sequences prediction, the functional domains that characterize the studied enzymes were confirmed. The domains were identified using the NCBI's “CDD” algorithm. Signal peptides and transmembrane domains were identified using Phobius. On average, one CHS gene, 7 CDAs and 8 CHTs were identified in the three species studied. The identified genes were conserved across species. For the analysis of gene expression by RT-qPCR, D. saccharalis was used as a model species for treatments with insecticides. In the treatment with Bt, there was an increase in the expression of a CDA gene and a decrease in the expression of two chitinase genes. On the other hand, treatment with lufenuron showed a relative increase in the expression of a CDA and a chitinase, and a decrease in the expression of two other chitinases. Whether these genes have their relative expression increased or decreased by the direct action of insecticides, or whether this variation is a secondary physiological response of the insect to remodeling during PM repair is still elusive. A better understanding of the molecular responses of genes involved in peritrophic membrane metabolism could help improve pest management tactics.

BANKING MEMBERS:
Presidente - 3086812 - JOSE DIJAIR ANTONINO DE SOUZA JUNIOR
Interno - ***.976.374-** - MARCELO HENRIQUE SANTOS PAIVA - UFPE
Externo à Instituição - LEONARDO LIMA PEPINO DE MACEDO - EMBRAPA