Mildew resistance locus O (MLO) is a plant-specific gene family that plays an important role in the growth and development of plants and their interactions with the environment. However, the available information on this gene family in pear is limited. Here, 24 PbrMLO genes were identified and divided into five subfamilies (I, II, III, IV and V). Whole-genome duplication (WGD) and dispersed duplication contributed to the expansion of the PbrMLO family. In addition, gene expression analysis revealed that PbrMLO genes were distributed in various pear tissues, suggesting their diverse functions. We selected PbrMLO23 for further functional analysis. Expression profile analysis by qRT-PCR showed that PbrMLO23 was highly expressed in pollen. Subcellular localization analysis showed that PbrMLO23 was located on the plasma membrane. When the expression level of PbrMLO23 was knocked down by using antisense oligonucleotides, pollen tube lengths increased, indicating that PbrMLO23 plays a functional role in inhibiting pollen tube growth. In summary, these results provide evolutionary insight into PbrMLO and its functional characteristics and lay a foundation for further analysis of the functions of PbrMLO members in pear.

抗霉病基因座O（MLO）是植物特有的基因家族，在植物的生长发育及其与环境的相互作用中起着重要作用。然而，关于梨中这个基因家族的可用信息是有限的。在这里，鉴定了24 个PbrMLO基因并将其分为五个亚家族（I、II、III、IV 和 V）。全基因组重复 (WGD) 和分散重复有助于PbrMLO家族的扩展。此外，基因表达分析显示PbrMLO基因分布在各种梨组织中，表明其功能多样。我们选择了PbrMLO23用于进一步的功能分析。qRT-PCR 表达谱分析表明PbrMLO23在花粉中高表达。亚细胞定位分析表明 PbrMLO23 位于质膜上。当使用反义寡核苷酸敲低PbrMLO23的表达水平时，花粉管长度增加，表明PbrMLO23在抑制花粉管生长方面发挥了功能性作用。总之，这些结果提供了对PbrMLO及其功能特征的进化洞察，并为进一步分析PbrMLO成员在梨中的功能奠定了基础。