Babesia bovis, an intraerythrocytic hemoprotozoan parasite, causes the most pathogenic form of bovine babesiosis, negatively impacting the cattle industry. Comprehensive knowledge of B. bovis biology is necessary for developing control methods. In cattle, B. bovis invades the red blood cells (RBCs) and reproduces asexually. Micronemal proteins, which bind to sialic acid of host cells via their microneme adhesive repeat (MAR) domains, are believed to play a key role in host cell invasion by apicomplexan parasites. In this study, we successfully deleted the region encoding MAR domain of the BBOV_III011730 by integrating a fusion gene of enhanced green fluorescent protein-blasticidin-S-deaminase into the genome of B. bovis. The transgenic B. bovis, lacking the MAR domain of the BBOV_III011730, invaded bovine RBCs in vitro and grew at rates similar to the parental line. In conclusion, our study revealed that the MAR domain is non-essential for the intraerythrocytic development of B. bovis in vitro.

牛巴贝斯虫是一种红细胞内血液原生动物寄生虫，可引起最具致病性的牛巴贝斯虫病，对养牛业产生负面影响。牛双歧杆菌生物学的全面知识对于开发控制方法是必要的。在牛体内，牛双歧杆菌侵入红细胞(RBC) 并进行无性繁殖。微线体蛋白通过其微线体粘附重复（MAR）结构域与宿主细胞的唾液酸结合，被认为在顶复门寄生虫入侵宿主细胞中发挥关键作用。在本研究中，我们通过将增强型绿色荧光蛋白-杀稻瘟菌素-S-脱氨酶融合基因整合到牛芽孢杆菌基因组中，成功删除了编码BBOV_III011730的MAR结构域的区域。缺乏 BBOV_III011730 的 MAR 结构域的转基因牛双歧杆菌在体外侵入牛红细胞，并以与亲本系相似的速度生长。总之，我们的研究表明，MAR 结构域对于B的红细胞内发育不是必需的。牛体外。