Effect of Hsp83 on the survival and reproductive fitness in the fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae)

Hsp90 family plays multiple roles in organisms. Here, we investigated the function of Hsp83 (Hsp90 member) in Spodoptera frugiperda for the first time. The obtained SfHsp83 contains the HATPase_c and HSP90 domains, as well as the Hsp family signature sequence YSNKEIFLRE, and four Hsp90 characteristic sequences. The expression of SfHsp83 in the adult stage is relatively higher than other stages. SfHsp83 exhibited the highest expression in the abdomen and head of female adults. Heat stress (but cold stress did not) significantly induced the up-regulation of SfHsp83 in female adults but not in males, and Staphylococcus aureus stress (but Escherichia coli and Bacillus subtilis stresses did not) significantly induced the up-regulation of SfHsp83 in the larvae. RNAi significantly knocked down the expression of SfHsp83 in female adults, with a reduction rate of over 60%. Biological assay showed that SfHsp83 RNAi significantly increased (up to 30%) the mortality of female adults under heat or bacteria stress, and significantly decreased female fecundity (reduced 50%) and egg-hatching rate (reduced 30%). RNAi also negatively affected ovarian development and oviposition behavior of females. To our knowledge, this is the first study to investigate the function of Hsp83 using RNAi in Lepidoptera, and the results have provided an in-depth understanding of the functional pleiotropy and evolutionary significance of Hsp83 in moths.