miRNA targeting <i>Mpp53</i> is involved in UV‐B irradiation resistance in <i>Myzus persicae</i>

Ultraviolet (UV) radiation, an environmental stressor, is crucial for the survival and adaptation of organisms. Myzus persicae, a global pest, is exposed to sunlight year-round, making it unable to avoid UV rays in its environment. MicroRNAs (miRNAs) are important posttranscriptional regulators of gene expression and mediate various biological processes. However, the role of miRNA in aphids in response to UV-B stress is unclear. In this study, Mpp53 expression level significantly increased with an increase in the duration of UV-B radiation, peaking at 2 h; knockdown of Mpp53 decreased the survival rate of aphids under UV-B stress, suggesting that Mpp53 is involved in aphid responses to UV-B. Here, we first predicted 8 miRNAs targeting Mpp53, and then screened for miRNAs related to UV-B resistance in aphids; of these, 5 miRNAs (miR-305-5p, novel_50, novel_80, novel_166, and novel_61) were found to target Mpp53. Luciferase reporter assays demonstrated that novel_61 binds to the noncoding region of Mpp53 and downregulates its expression. Overexpression of novel_61 in aphids decreased Mpp53 expression and caused significant mortality under UV-B irradiation. Furthermore, the aphids exhibited lower reproductive capacity, lower body weight, and shorter body length and width. This is the first study to systematically screen and identify miRNA related to aphid responses to UV-B stress and deepens our understanding of the molecular mechanism of insect responses to environmental stress, which may eventually aid in developing better control strategies.