CPR Gene Contributes to Integument Function and Ovary Development in a Rice Planthopper

Area of Science:

• Insect physiology
• Biochemistry
• Molecular biology

Background:

• Nicotinamide adenine dinucleotide phosphate (NADPH)-cytochrome P450 reductase (CPR) is crucial for electron transfer to cytochrome P450 enzymes.
• CPR plays a key role in cuticular hydrocarbon (CHC) synthesis, essential for insect development and survival.

Purpose of the Study:

• To elucidate the physiological functions of the CPR gene in the rice pest Nilaparvata lugens.
• To investigate the impact of CPR gene knockdown on insect integument, CHC synthesis, and reproductive capabilities.

Main Methods:

• RNA interference (RNAi) was employed to knock down CPR gene expression in Nilaparvata lugens adults.
• Scanning electron microscopy (SEM) was used to examine cuticle structure.
• Gas chromatography-mass spectrometry (GC-MS) analyzed cuticular hydrocarbon profiles.
• Ovary morphology and egg-laying were assessed in treated insects.

Main Results:

• CPR gene knockdown resulted in impaired waterproofing and water retention in adult female insects.
• SEM revealed a thinner lipid layer on the abdominal cuticle of CPR-deficient adults.
• CHC analysis showed significantly reduced levels of long-chain hydrocarbons (≥ C27).
• Ovaries exhibited developmental defects, including deformed oocytes and a complete failure of egg-laying.

Conclusions:

• CPR is essential for maintaining insect integument integrity and waterproofing through CHC biosynthesis.
• The CPR gene plays critical roles in both CHC production and successful embryo development in Nilaparvata lugens.
• These findings highlight CPR's multifaceted importance for insect survival and reproduction.