Developmental and Light-Induced Expression Patterns of Phototransduction Pathway Genes in Large Yellow Croaker (Larimichthys crocea).

BACKGROUND

The visual system plays critical roles in fish feeding, predator avoidance, and reproduction, with the phototransduction pathway serving as the core molecular mechanism of visual signal transduction. This study represents the first systematic analysis of phototransduction-related genes in large yellow croaker (Larimichthys crocea).

METHODS

Bioinformatics, transcriptomic analysis, and RT-qPCR were used to identify phototransduction-related genes in large yellow croaker and analyze their developmental expression patterns and responses to different light spectra.

RESULTS

Thirty phototransduction-related genes were identified, including genes involved in light perception, signal amplification, and signal termination and recovery. Structural analyses indicated that these genes were highly conserved in teleosts. Most genes showed low expression during 1-7 days post-hatching (dph), increased expression during 7-24 dph, and stable expression during 24-35 dph. Collectively, these results identify 15-24 dph as a critical developmental window for visual system maturation in large yellow croaker larvae. Under different spectral treatments at 15 dph, phototransduction-related genes exhibited wavelength-dependent expression patterns. Under the present experimental conditions, relatively higher expression levels of most phototransduction-related genes were observed under blue- and green-light treatments, whereas relatively lower expression levels were observed under the red-light treatment. Key downstream genes, including gucy2f, guca1d, calml4a, and rgs9b, were significantly affected by different light spectra.

CONCLUSIONS

This study revealed the developmental dynamics and spectral response characteristics of phototransduction-related genes in the large yellow croaker. These findings provide new insights into teleost visual development and light adaptation and provide a molecular basis for future studies aimed at optimizing light conditions during larval rearing in large yellow croaker aquaculture.