Transcriptome Analysis of the Fat Body of the Maize Pest Delphacodes kuscheli (Hemiptera: Delphacidae) Reveals Essential Roles of Fungal Endosymbionts

The fat body of certain insects, in addition to performing essential biosynthetic and metabolic functions, harbors endosymbionts that play critical roles for their host. While knowledge of the diversity and functions of fungal endosymbionts harbored in the fat body of planthoppers is mostly limited to rice pests of Asia, our study presents a comprehensive transcriptomic analysis of the fat body of Delphacodes kuscheli (Hemiptera: Delphacidae), an important agricultural pest of maize in Argentina. The dominant fungal endosymbionts, identified as yeast-like symbionts (YLS), include members of the genera Ophiocordyceps, Cordyceps, Hirsutella, and Tolypocladium (Ascomycota: Hypocreales). Transcriptomic data reveal that the fungal endosymbionts encode genes involved in vital metabolic processes for the host, such as essential amino acid biosynthesis, nitrogen recycling, and steroid biosynthesis. The genetic contribution of these endosymbionts to nutrient provision and metabolism supports a mutualistic obligate relationship with D. kuscheli. The results presented here provide insights into the evolutionary dynamics of endosymbiosis in the Delphacidae. Furthermore, this study highlights the potential of YLS as promising targets for innovative pest control strategies.