Available online 11 May 2022, 104399

Spodoptera frugiperda genome contains two genes encoding prophenoloxidases.

SfPPOs complement one another for hemolymph phenoloxidase activity.

SfPPO1Δ,PPO2Δ double mutant presents morphological defects during pupal stage.

SfPPO1Δ,PPO2Δ double mutant pupae are not able to develop into adults.

Upon infection, the phenoloxidase system in arthropods is rapidly mobilized and constitutes a major defense system against invaders. The activation of the key enzymes prophenoloxidase (PPO) and their action in immunity through melanization and encapsulation of foreign bodies in hemolymph has been described in many insects. On the other hand, little is known about PPOs involvement in other essential functions related to insect development.

In this paper, we investigated the function of the two PPOs of the crop pest, Spodoptera frugiperda (PPO1 and PPO2). We show that PPOs are mainly expressed in hemocytes with the PPO2 expressed at higher levels than the PPO1. In addition, these two genes are expressed in the same tissue and at the same stages of insect development. Through the generation of loss-of-function mutants by CRISPR/Cas9 method, we show that the presence of PPOs is essential for the normal development of the pupa and the survival of the insect.

Phenoloxidase

CRISPR

melanization

development

Spodoptera frugiperda

Fall armyworm

Lepidoptera

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