<![CDATA[Heat shock protein 90 (Hsp90) is highly conserved molecular chaperone chaperone involved in cellular stress responses and has been implicated in insect–virus interactions. This study aimed to characterize the Hsp90 gene (PnHsp90) of Pentalonia nigronervosa, the principal vector of banana bunchy top virus (BBTV), and to investigate its transcriptional dynamics during virus acquisition. RNA-seq datasets (SRX6918251 and SRX6918252) were retrieved from GenBank for PnHsp90 identification and subsequent physicochemical, structural, and phylogenetic analyses using ProtParam, CYS-REC, I-TASSER, SWISS-MODEL, and MEGA X. PnHsp90 encodes a protein of 726 amino acids with an acidic theoretical isoelectric point (pI = 4.94), a high aliphatic index (82.84), and a conserved EEVD motif characteristic of cytosolic Hsp90s proteins. Structural modelling based on the Saccharomyces cerevisiae Hsp90–Sba1 complex (PDB: 2C9B) generated a reliable tertiary structure (TM-score = 0.72), supporting the conservation of Hsp90 domain architecture. Phylogenetic analysis placed PnHsp90 in a clade closely related to Myzus persicae, consistent with aphid evolutionary relationships. Quantitative real-time PCR revealed a biphasic transcriptional response during acquisition access periods (AAPs), characterized by rapid induction at 1 hour (2.5-fold), marked downregulation at 5 and 10 h, and renewed upregulation at 20 hours (1.7-fold). The dynamic expression profile suggests that PnHsp90 is involved in the physiological responses of P. nigronervosa during both the early and later stages of BBTV acquisition. This study provides the first integrative characterization of PnHsp90 and identifies it as a promising candidate for future functional studies aimed at elucidating the molecular mechanisms underlying BBTV acquisition and vector competence.]]>
