Sun Hui, Hua Jixiang, Tao Yifan, He Jie, Wang Qingchun, Dong Yalun, He Jixiang, Qiang Jun
Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China.
Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China; Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, 214081, China.
Fish Shellfish Immunol. 2025 Oct;165:110558. doi: 10.1016/j.fsi.2025.110558. Epub 2025 Jul 8.
Largemouth bass ranavirus (LMBV) is a serious threat to aquacultured largemouth bass (Micropterus salmoides) because it is highly infectious and lethal. Our research group has carried out genetic improvement of largemouth bass with LMBV resistance as a target trait through family selection, combined with molecular marker-assisted selection, using the northern U.S.A. subspecies of largemouth bass as a foundation population. By 2023, we had generated 35 F generation LMBV-resistant families. The top six lines with the highest survival rates were selected through LMBV virus challenge experiments, leading to the construction of an F-generation resistant population (SF) in 2024. After LMBV virus infection, the 7-day survival rate of the SF population was 28.9 % higher than that of the unselected control population (CF). Whole genome resequencing revealed higher genetic diversity of the SF population (PIC = 0.1557 vs. 0.1029, Ao = 1.8935 vs. 1.4329, Ho = 0.1647 vs. 0.1146) compared with the CF population. Forty-nine genomic regions selected in the SF population vs. the CF population were identified by selective scanning analysis (F-ZHp/F-θπ), and 169 candidate genes were localized. Among them, the immune regulation-related genes atp7b, nampt, hpcal4, and ppsst1/2 were identified as key candidate genes for disease resistance under intensive selection in the SF population. These results provide new information about the genetic mechanism of LMBV resistance in largemouth bass, and theoretical support for further research on virus resistance and the selection of disease-resistant varieties. The identified genes and genomic regions are of great significance for the precision breeding of largemouth bass.
大口黑鲈蛙病毒（LMBV）对水产养殖的大口黑鲈（Micropterus salmoides）构成严重威胁，因为它具有高度传染性和致死性。我们的研究小组以美国北部大口黑鲈亚种为基础群体，通过家系选择并结合分子标记辅助选择，对大口黑鲈进行了以抗LMBV为目标性状的遗传改良。到2023年，我们已培育出35个F代抗LMBV的家系。通过LMBV病毒攻毒实验，筛选出存活率最高的前六个家系，于2024年构建了F代抗性群体（SF）。LMBV病毒感染后，SF群体的7天存活率比未选择的对照群体（CF）高28.9%。全基因组重测序显示，与CF群体相比，SF群体具有更高的遗传多样性（PIC = 0.1557对0.1029，Ao = 1.8935对1.4329，Ho = 0.1647对0.1146）。通过选择性扫描分析（F-ZHp/F-θπ），在SF群体与CF群体中鉴定出49个基因组区域，并定位了169个候选基因。其中，免疫调节相关基因atp7b、nampt、hpcal4和ppsst1/2被确定为SF群体在高强度选择下抗病的关键候选基因。这些结果为大口黑鲈抗LMBV的遗传机制提供了新信息，为进一步开展病毒抗性研究和抗病品种选育提供了理论支持。所鉴定的基因和基因组区域对大口黑鲈的精准育种具有重要意义。
