The three rice planthoppers, including Nilaparvata lugens, Sogatella furcifera, and Laodelphax striatellus, represented significant agricultural pests that affected rice production. Extended insecticide application resulted in these three species developing resistance to multiple chemical compounds. Among these species, N. lugens demonstrated the most accelerated resistance evolution, especially against neonicotinoid insecticides; S. furcifera and L. striatellus developed resistance more gradually and generally maintained high susceptibility to most insecticides, though increasing resistance to buprofezin presented an emerging concern. These species enhanced their detoxification capabilities through the upregulation of metabolic enzymes, including cytochrome P450 monooxygenase (CYP450) and glutathione S-transferase (GST). The resistance in N. lugens primarily stemmed from metabolic mechanisms, particularly the enhanced expression of detoxification enzymes such as CYP450, coupled with adaptive target-site mutations and co-evolution with resistant rice varieties. For S. furcifera, resistance predominantly related to target-site mutations, with frequent mutations in target proteins, while metabolic mechanisms also contributed significantly. In contrast, L. striatellus exhibited comparatively lower resistance levels, with target-site modifications serving as the primary mechanism and limited involvement of detoxification enzymes, which resulted in slower resistance development. These species also displayed distinctive characteristics regarding resistance-related gene regulation, symbiont bacteria interactions, and adaptive metabolic responses. This review synthesizes current knowledge of resistance development, fundamental molecular mechanisms, and recent research advances in these rice planthoppers, while proposing molecular-based resistance management approaches to facilitate effective and sustainable pest control.

Heat shock proteins (HSPs) are indispensable molecular chaperones that play critical roles in insects under various stress conditions. Previous studies have demonstrated that HSPs are involved in the growth, development, responses to abiotic stress, host interactions, and insecticide resistance in the three major rice planthoppers. In this study, we systematically identified and characterized the HSP gene family members in the brown planthopper (Nilaparvata lugens), the white-backed planthopper (Sogatella furcifera), and the small brown planthopper (Laodelphax striatellus). A total of 70, 55, and 86 HSP genes were identified in these three species, respectively. Phylogenetic analysis incorporating a large set of outgroup HSP genes revealed that rice planthopper HSPs can be classified into eight families: sHSP, CCT, HSP60, HSP10, DNAJ, HSP90, HSP70, and HSP100, with DNAJ being the most abundant. In contrast, HSP10, HSP60, HSP90, and HSP100 families each contained only 1~4 members. Substantial variation was observed in molecular weight, amino acid number, and protein sequence length among different HSP families, whereas members within the same family were relatively conserved. Collinearity analysis indicated that HSP family members exhibited highly similar chromosomal distributions across the three rice planthoppers. Systematic analysis of conserved motif and domain further showed that DNAJ family members possessed the greatest diversity of additional functional domains, whereas HSP70, HSP90, HSP10, CCT, and HSP60 families were highly conserved. Moreover, transcriptome-based expression profiling revealed distinct expression patterns of HSP genes across different developmental stages, tissues, and under temperature stress in the three planthopper species, which were further validated for selected HSP genes under different thermal conditions. Collectively, this study provides fundamental insights and valuable genetic resources for understanding the functional diversity, evolutionary dynamics, and ecological adaptation roles of the HSP gene families in planthoppers.