The impact of neurohormone silencing on the molting process in Delphacodes kuscheli: insights and implication

NICOLAS ANDRADA; MARCOS STERKEL; MARIA INES CATALANO

Ciudad autónoma de Buenos Aires

Congreso; VII congress of Latin American Association of chemical Ecology; 2023

Facultad de Cienciass Exactas - UBA

Molting is an essential process in which an insect replaces its cuticle to support its growth. This process is regulated by enzymes and peptidic hormones. These hormones, known as neuropeptides, are short-lived molecules responsible for governing the molting process. In this research, we wanted to identify and characterize in silico a couple of neuropeptides responsible for regulating the molting process in D. kuscheli, the main vector of Mal de Río Cuarto Virus (MRCV). Additionally, we aimed to assess the functions of these neuropeptides in insect growth and development. Through a transcriptome search, we have identified the genes responsible for encoding the Ecdysis Triggering Hormone (ETH), which plays a key role in the insect´s escape from its old exoskeleton, and Bursicon-α (Burs-α), which plays a vital role in the hardening of the new exoskeleton and the expansion of wings in adults. Subsequently, we conducted phylogenetic analyses. Then, we perform silencing assays to investigate their roles in the molting process. To do this, we synthesized double-stranded RNAi (dsRNAETH and dsRNABurs-α) and injected them into 5th-stage nymphs´ intra-abdominal regions at a concentration of 0.3 Ul in a 500 ng/ul solution. Our observations revealed that insects subjected to dsRNAETH exhibited a delay in the molting. Normally, D. kuscheli insects take around 4 to 5 days to complete molting. However, those with dsRNAETH remained in the nymph stage for approximately 8 days and finally died. Some of them attempted to molt but exhibited abnormalities in the process. Additionally, when using dsRNABurs-α, the insects developed wing abnormalities, which hindered their proper locomotion, ultimately leading to their demise within a few days. These findings suggest the critical roles of ETH and Bursicon-α in the molting and development of D. kuscheli insects. These findings suggest the critical roles of ETH and Bursicon-α in the molting and development of D. kuscheli insects.