The production of reactive oxygen species (ROS) by NADPH oxidase, which is also referred to as respiratory burst oxidase homolog (RBOH), affects several processes in plants. However, the role of RBOHs in cell wall lignification is not well understood. In this study, we show that PuRBOHF, an RBOH isoform, plays an important role in secondary wall formation in pear stone cells. ROS were closely associated with lignin deposition and stone cell formation according to microscopy data. In addition, according to the results of an in situ hybridization analysis, the stage-specific expression of PuRBOHF was higher in stone cells than in cells of other flesh tissues. Inhibitors of RBOH activity suppressed ROS accumulation and stone cell lignification in pear fruit. Moreover, transient overexpression of PuRBOHF caused significant changes in the amount of ROS and lignin that accumulated in pear fruit and flesh calli. We further showed that PuMYB169 regulates PuRBOHF expression, while PuRBOHF-derived ROS induces the transcription of PuPOD2 and PuLAC2. The findings of this study indicate that PuRBOHF-mediated ROS production, which is regulated by a lignin-related transcriptional network, is essential for monolignol polymerization and stone cell formation in pear fruit.

NADPH 氧化酶（也称为呼吸爆发氧化酶同源物 (RBOH)）产生的活性氧 (ROS) 会影响植物中的多个过程。然而，RBOH 在细胞壁木质化中的作用尚不清楚。在这项研究中，我们表明，PuRBOHF是一种 RBOH 异构体，在梨石细胞的次生壁形成中起着重要作用。根据显微镜数据，ROS与木质素沉积和石细胞形成密切相关。此外，根据原位杂交分析的结果，PuRBOHF的阶段特异性表达在石细胞中高于其他肉组织细胞。RBOH 活性抑制剂抑制梨果实中的 ROS 积累和石细胞木质化。此外，PuRBOHF 的瞬时过表达导致梨果实和果肉愈伤组织中积累的 ROS 和木质素的数量发生显着变化。我们进一步表明 PuMYB169 调节PuRBOHF表达，而PuRBOHF衍生的 ROS 诱导PuPOD2和PuLAC2的转录。该研究的结果表明，PuRBOHF介导的 ROS 产生由木质素相关转录网络调节，对于梨果实中的木质素聚合和石细胞形成至关重要。