The genetic mechanisms underlying diapause in agricultural pests

• Grant number: 21/11999-5
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: February 05, 2022
• End date: January 31, 2023
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Principal Investigator: Alberto Soares Corrêa
• Grantee: Frederico Hickmann
• Supervisor: Andy Michel
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Institution abroad: Ohio State University, Wooster, United States
• Associated to the scholarship: 18/20351-6 - Dormancy and host adaptation of two allopatric lineages of Euschistus heros (Hemiptera: Pentatomidae), BP.DR

Abstract

Climatic conditions vary strongly with latitude and usually are directly linked to the establishment of a species. Diapause is a neurohormonal mechanism of developmental suppression used by arthropods to survive unfavorable climate conditions. The genus Euschistus is one of the most important soybean pests in the Americas (e.g. Euschistus heros is a key soybean pest in Brazil) and express a facultative adult diapause induced in the immature stages. In Brazil occur two strains of E. heros, one occurs in the North/Northeast region under lower latitudes and another in the South region under higher latitudes with a hybridization zone in the Cerrado. Also, we reported the occurrence of two other Euschistus species (E. taurulus, found from Venezuela to Uruguay and E. crenator, found from the south USA to the north of Brazil) on soybean fields in Brazil. Questions about the potential of Eushistus groups to adapt to abiotic conditions can help understand their population dynamics and pest potential. Therefore, our objectives here are to identify (via RNAseq) and characterize (via RNA interference) candidate genes in Euschistus stink bugs that are associated with diapause. To achieve our goals, the two strains and two sister species were exposed to different light regimes (short and long daylength) at 25 ºC and their RNA was extracted. Subsequently, a transcriptome analysis (RNAseq) will be performed on the South Strain of E. heros and E. taurulus (both express a stronger diapause), to identify the candidate genes associated with diapause. The RNAseq results will be validated using the candidate genes associated with diapause via RT-PCR. After, we will use a North American Pentatomidae species (Euschistus servus (Say)) to characterize the role of the candidate genes in the diapause phenotype using RNAi technology. With this approach, we hope to identify the genetic mechanisms underlying diapause in stink bugs, especially from the Euschistus group which could serve as targets to better control and manage these important agricultural pests. (AU)