Genome-wide identification and expression analyses of HSP90 genes in cassava (Manihot esculenta).

Heat shock proteins (HSPs) play a crucial role in plant thermotolerance responses. While the regulatory mechanisms of HSPs in Manihot esculenta have been extensively studied, current understanding of the HSP90 gene family, which serves as key regulators in high-temperature adaptation, remains limited in M. esculenta research. HSP90 not only influences M. esculenta growth and development but also significantly affects starch content, ultimately impacting yield. In this study, we identified and characterized 11 HSP90 genes in the M. esculenta genome, which are randomly distributed across seven chromosomes. These genes contain 10 conserved motifs and exhibit variable intron numbers (1-19), suggesting their broad involvement in regulatory networks. Phylogenetic analysis revealed high homology between M. esculenta HSP90 genes and those in Solanum tuberosum. Quantitative real-time PCR demonstrated distinct expression patterns of HSP90 genes under 43 °C heat stress, with significant tissue-specific variations. These findings address a critical knowledge gap by elucidating the cascade effects of HSP90 within the HSP family. Importantly, our results not only clarify the unique regulatory role of HSP90 in M. esculenta 's heat stress response but also reveal its molecular mechanism in high temperature adaptation through starch biosynthesis regulation, providing valuable molecular targets and theoretical foundations for developing heat-tolerant M. esculenta cultivars.