Regulatory mutations upstream of ppp2ca affect body weight in Asian seabass

Growth is one of the most economically important traits in aquaculture. In a previous study, the ppp2ca gene was identified within a major quantitative trait locus (QTL) for growth in Asian seabass. However, the genetic mechanisms through which ppp2ca regulates growth remain unclear. In our study, a SNP in ppp2ca was significantly associated with increased body weight. ppp2ca was ubiquitously expressed in all 11 examined tissues with higher expression in the brain and eye. Its expression was reduced in muscle of fast-growing fish. Knockdown of ppp2ca promoted cell proliferation, while overexpression inhibited cell growth. We identified two naturally occurring mutations—a 10-bp insertion and a 218-bp deletion—upstream of ppp2ca . The 10-bp insertion increased expression of ppp2ca as compared to wild type and was associated with reduced body weight, while the 218-bp deletion mutant was significantly associated with growth and reduced the expression of ppp2ca compared to its wild type. These naturally occurring mutations not only serve as valuable markers for growth trait selection but also provide important targets for future studies on growth regulation in Asian seabass.