Identification of Diatraea saccharalis olfactory receptor in the insect-fungi interaction

• Grant number: 16/25634-0
• Support type: Scholarships in Brazil - Post-Doctorate
• Effective date (Start): April 01, 2017
• Effective date (End): March 31, 2021
• Field of knowledge: Agronomical Sciences - Agronomy
• Principal Investigator: José Maurício Simões Bento
• Grantee: Flávia Pereira Franco
• Home Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated scholarship(s): 18/15795-2 - Identification of Diatraea saccharalis Olfactory Receptor in the Insect-Fungi Interaction, BE.EP.PD

Abstract

Colonization of sugarcane stalk by opportunistic fungi, such as Fusarium verticillioides and Colletotrichum falcatum, usually occurs after Diatraea saccharalis (Lepidoptera: Crambidae) caterpillars attack. Previous studies have been shown an important synergistic relationship between D. saccharalis and these fungi on sugarcane. Our data suggests that D. saccharalis caterpillars create a favorable environment to C. falcatum infection in sugarcane, which increase the fungus concentration in attacked plants. In addition, both fungi, C. falcatum and F. verticillioides, have been shown a double effect on D. saccharalis caterpillar, they promote a strong attraction for insects and positively influence D. saccharalis feeding and weight gain in diets with fungi. An olfactory choice assay showed that D. saccharalis is attracted by volatiles compounds emitted by C. falcatum and F. verticillioides. We can highlight the compounds acoradiene and acorenol (manuscript in preparation). From this knowledge, the goal of this project is to identify and to characterize D. saccharalis Odorant Receptors (OR) responsive to these fungal volatiles. For this approach, we will use techniques such as next generation sequencing, to identify sequences and expression profiles of encoding genes to odorant receptors in D. saccharalis caterpillars antennae; cloning and expression of these genes in Xenopus laevis oocytes, for identification and characterization of active receptors responsive to the fungal volatiles and; reduction of gene expression/silencing by RNAi to confirm the OR activity by behavior assay and validation of results. This new challenge will decipher another stage of the complex network of plant-insect-fungus interaction, and can reveal important targets for the development of biotechnological strategies to D. saccharalis control. (AU)