School of Life Sciences, Guizhou Normal University, Gui'an, Guizhou, China.
Qiannan Normal University for Nationalities, Duyun, Guizhou, China.
PLoS One. 2024 May 7;19(5):e0302992. doi: 10.1371/journal.pone.0302992. eCollection 2024.
Bean beetle (Callosobruchus maculatus) exhibits clear phenotypic plasticity depending on population density; However, the underlying molecular mechanism remains unknown. Compared to low-density individuals, high-density individuals showed a faster terminal oocyte maturity rate. Four insulin-like peptide (ILP) genes were identified in the bean beetle, which had higher expression levels in the head than in the thorax and abdomen. The population density could regulate the expression levels of CmILP1-3, CmILP2-3, and CmILP1 as well as CmILP3 in the head, thorax, and abdomen, respectively. RNA interference results showed that each CmILP could regulate terminal oocyte maturity rate, indicating that there was functional redundancy among CmILPs. Silencing each CmILP could lead to down-regulation of some other CmILPs, however, CmILP3 was up-regulated in the abdomen after silencing CmILP1 or CmILP2. Compared to single gene silencing, silencing CmILP3 with CmILP1 or CmILP2 at the same time led to more serious retardation in oocyte development, suggesting CmILP3 could be up-regulated to functionally compensate for the down-regulation of CmILP1 and CmILP2. In conclusion, population density-dependent plasticity in terminal oocyte maturity rate of bean beetle was regulated by CmILPs, which exhibited gene redundancy and gene compensation.
豆象（Callosobruchus maculatus）表现出明显的表型可塑性，取决于种群密度；然而，其潜在的分子机制尚不清楚。与低密度个体相比，高密度个体的终末卵母细胞成熟速度更快。在豆象中鉴定出了四个胰岛素样肽（ILP）基因，它们在头部的表达水平高于胸部和腹部。种群密度可以调节头部、胸部和腹部中 CmILP1-3、CmILP2-3 和 CmILP1 以及 CmILP3 的表达水平。RNA 干扰结果表明，每个 CmILP 都可以调节终末卵母细胞成熟率，表明 CmILPs 之间存在功能冗余。沉默每个 CmILP 都会导致其他一些 CmILPs 的下调，但在沉默 CmILP1 或 CmILP2 后，CmILP3 在腹部被上调。与单基因沉默相比，同时沉默 CmILP3 与 CmILP1 或 CmILP2 会导致卵母细胞发育更严重的延迟，这表明 CmILP3 可以被上调以在功能上补偿 CmILP1 和 CmILP2 的下调。总之，豆象终末卵母细胞成熟率的种群密度依赖性可塑性受 CmILPs 调节，这些基因表现出基因冗余和基因补偿。
