A chromosome-level genome assembly and developmental transcriptome profiling reveal stage-specific remodeling of the molecular chaperone system in Helicoverpa armigera

Helicoverpa armigera is one of the most destructive lepidopteran pests worldwide owing to its remarkable polyphagy, long-distance migration, and rapid adaptation to insecticides. Here, we present a chromosome-level genome assembly of H. armigera generated from a field-collected individual in southwestern China, providing a valuable resource for future population genomic and pangenome studies. Developmental transcriptome analyses of first-instar larvae, fifth-instar larvae, and adults identified 6817, 3519, and 5518 differentially expressed genes, respectively, including 797 shared among all developmental transitions. Functional enrichment and co-expression network analyses revealed extensive transcriptional reprogramming, characterized by coordinated regulation of glycolysis, the tricarboxylic acid (TCA) cycle, and fatty acid β-oxidation, indicating dynamic metabolic remodeling during development. Genome-wide analysis identified 77 heat shock protein (HSP) genes belonging to six subfamilies. These genes were unevenly distributed across chromosomes, with HSP20 members exhibiting extensive tandem duplication. Expression profiling revealed pronounced stage specificity, suggesting progressive remodeling of molecular chaperone networks during development. Early larvae primarily relied on HSP40/HSP60/HSP70 and HSP10/HSP60 chaperone systems; fifth-instar larvae exhibited HSP20-centered proteostasis; and adults predominantly expressed HSP40 together with multiple HSP70 members, accompanied by enrichment of stress response and metamorphosis-related functions. This study provides new insights into developmental transcriptional regulation, metabolic remodeling, and stage-specific specialization of molecular chaperone networks in H. armigera, establishing a foundation for future studies of stress adaptation, population genomic variation, and developmental mechanisms.