The Phosphoserine Phosphatase Alters the Free Amino Acid Compositions and Fecundity in Reuter.

The mirid bug (Reuter) is an important predator that consumes eggs and young nymphs of the brown planthopper as a primary food source and thus becomes an important member of the rice ecosystem. We identified and characterized the gene in encoding the phosphoserine phosphatase enzyme. The has an open reading frame (ORF) of 957 bp encoding a protein with a length of 294bp and it possesses a haloacid dehalogenase-like (HAD) hydrolase, phosphoserine phosphatase, eukaryotic-like (HAD_PSP_eu) conserved domain. Furthermore, the in silico analysis of the gene unveiled its distinct characteristics and it serves as a key player in the modulation of amino acids. The showed expression in all developmental stages, with higher expression observed in the ovary and fat body. Silencing the by RNA interference (RNAi) significantly decreased PSP enzyme activity and expression compared to dsGFP at two days after emergence (2DAE). The dsPSP treatment altered free hemolymph amino acid compositions, resulting in a significant reduction of serine (Ser) and Arginine (Arg) proportions and a significant increase of Threonine (Thr), Cystine (Cys), and Tyrosine (Tyr) in the female at 2 DAE. Additionally, a hindered total protein concentration in the ovary and fat body, and reduced expression, body weight, and number of laid eggs, were also observed. The same treatment also prolonged the preoviposition period and hindered ovarian development. Our data, for the first time, demonstrated the influential role of the gene in modulating the fecundity of and provide a platform for future insect pest control programs using the gene in modulating fecundity.