Nitric oxide synthase is required for the pea aphid's defence against bacterial infection

Abstract

Compared to other insects, the pea aphid Acyrthosiphon pisum has a reduced immune system with an absence of genes coding for a lot of immunity-related molecules.Notably, nitric oxide synthase (NOS), which catalyses the synthesis of nitric oxide (NO), is present in the pea aphid. However, the role of NO in the immune system of pea aphid remains unclear. In this study, we explored the role of NO in the defence of the pea aphid against bacterial infections and found that the NOS gene of the pea aphid responded to an immune challenge, with the expression of ApNOS observably upregulated after bacterial infections. Knockdown of ApNOS using RNA interference or inhibition of NOS activity increased the number of live bacterial cells in aphids and the mortality of aphids after bacterial infection. Conversely, the increase in NO level in aphids using NO donor inhibited the bacterial growth, increased the survival of bacteriainfected aphids, and upregulated immune genes, such as Toll pathway and phagocytosis related genes. Thus, NO promotes immune responses and plays an important role in the immune system of pea aphid.

Identification of immune‐related genes from the transcriptome of the venom gland in Cotesia plutellae

“…NOS catalyzes the synthesis of nitric oxide (NO). In Acyrthosiphon pisum , NOS expression level was increased when infected with bacteria, and suppression of NOS elevated the lethality of bacteria‐infected A. pisum (Ma et al 2023). Cp‐SOD2 expression was higher than other Cp‐SODs (Fig.…”

Pleiotropic immunoregulation by growth‐blocking peptide in Ostrinia furnacalis

“…Compared with vertebrates that possess both innate and adaptive immunity, insects rely solely on their innate immune system to combat pathogen infection (Chen & Lu, 2018;Ma et al, 2023;Qiu et al, 2023). Insects have developed ways to recognise microbes through pattern recognition receptors that bind pathogenassociated molecular patterns and stimulate cellular and humoral immune responses (Chen et al, 2014(Chen et al, , 2016Shi et al, 2023;Wu & Yi, 2018).…”