Phaedrotoma sp.2 Parasitism on Host Liriomyza trifolii Metabolic and Immune Regulations by Transcriptome Analysis

Parasitoids are crucial natural enemies
of Liriomyza
trifolii, a globally notorious pest. Upon parasitization,
host metabolism and immune responses were profoundly disrupted, thereby
favoring the development of wasps offsprings. However, the underlying
regulatory mechanisms remain elusive. In this study, transcriptome
sequencing was utilized to investigate the host metabolic and immune
response changes at 4 h, 12 h, and 24 h postparasitization by Phaedrotoma sp.2. We identified 4070 differentially
expressed genes, enriched in metabolic (e.g., tricarboxylic acid cycle,
insulin synthesis) and immune (e.g., Toll/Imd pathways) pathways,
and RT-qPCR further validated core gene expressions involved in these
pathways. Physiological analyses revealed that Phaedrotoma sp.2 parasitism altered the host larvae’s protein, lipid,
and sugar content, inhibited hemocyte spreading, increased hemocyte
mortality, and suppressed hemolymph melanization. Collectively, this
study sheds light on the host metabolic and immune modulation by Phaedrotoma sp.2 parasitism and provides a novel
insight into the mechanisms underpinning their interactions. This
discovery lays a solid foundation for the practical application of
parasitoids in biological control programs.