Recently, the same fish diseases, which have been found in pond farming, have been found in the newly tested largemouth bass (Micropterus salmoides) system. Bacterial septicemia caused by Aeromonas hydrophila occurs frequently in largemouth bass culture leading to significant economic losses. To investigate the role miRNA in the largemouth bass disease resistance, twelve (2 tissues (spleen and head kidney) × 2 experimental groups (infected and control) × three biological replicates) small RNA libraries were constructed and sequenced with miRNA-seq. A total of 26 differentially expressed miRNAs, 8 upregulated and 18 downregulated, were identified in the spleen, and 19 differentially expressed miRNAs, 9 upregulated and 10 downregulated, were identified in head kidney (fold change ≥ 2 or ≤ 0.5 and P ≤ 0.05). The differentially expressed miRNAs with the largest fold change were selected for target gene prediction using GO and KEGG analysis. Six miRNAs in the spleen and 5 miRNAs in the head kidney were selected. Analysis showed that, of all the immune and metabolic pathways, the FoxO signaling pathway was enriched in both the spleen and head kidney groups. Common target genes of the pathway included AMP-activated catalytic subunit alpha 1 (prkaa1), phosphatidylinositol 3-kinase (pik3r3b), serine/threonine-protein kinase (plk2), and forkhead box protein G1 (foxg1a). MiRNAs (such as miR-126-5P, miR-126-3P) are involved in immune response and cell cycle functions as they regulate targeted genes in the FoxO pathway. These results will enhance our understanding of the molecular mechanisms underlying immune responses to bacterial septicemia and facilitate molecular-assisted selection of resistant strains of largemouth bass.

最近，在池塘养殖中发现的相同鱼病，在新测试的大口黑鲈（Micropterus salmoides）系统中也发现了。嗜水气单胞菌引起的细菌性败血症在大口黑鲈养殖中经常发生，导致重大的经济损失。为了研究 miRNA 在大嘴黑鲈抗病性中的作用，构建了 12 个（2 个组织（脾和头肾）×2 个实验组（感染和对照）×3 个生物重复）小 RNA 文库并用 miRNA-seq 测序。在脾脏中鉴定了总共26个差异表达的miRNA，8个上调和18个下调，在头肾中鉴定了19个差异表达的miRNA，9个上调和10个下调（倍数变化≥2或≤0.5和P ≤ 0.05)。使用GO和KEGG分析选择具有最大倍数变化的差异表达的miRNA用于靶基因预测。选择脾脏中的6个miRNA和头肾中的5个miRNA。分析表明，在所有免疫和代谢途径中，FoxO 信号通路在脾脏和头肾组中均富集。该途径的常见靶基因包括 AMP 激活的催化亚基 α1 ( prkaa1 )、磷脂酰肌醇 3-激酶 ( pik3r3b )、丝氨酸/苏氨酸蛋白激酶 ( plk2 ) 和叉头盒蛋白 G1 ( foxg1a)）。miRNA（如 miR-126-5P、miR-126-3P）参与免疫反应和细胞周期功能，因为它们调节 FoxO 通路中的靶基因。这些结果将增强我们对细菌败血症免疫反应的分子机制的理解，并促进分子辅助选择大口黑鲈抗性菌株。