Decoding the role of <i>OsPRX83</i> in enhancing osmotic stress tolerance in rice through ABA-dependent pathways and ROS scavenging

Plant Class III peroxidases have diverse roles in controlling root hair growth, anther development, and abiotic and biotic stress responses. However, their abiotic stress response mechanism in rice remains elusive. Here, we identified a peroxidase precursor gene, <i>OsPRX83</i>, and investigated its role in enhancing osmotic stress tolerance in rice. We used <i>OsPRX83</i> overexpression and CRISPR-Cas9-generated mutant lines to elucidate <i>OsPRX83</i>‘s function and expression patterns under stress conditions. The expression of <i>OsPRX83</i> was induced by H₂O₂, PEG, NaCl, and ABA treatments. Using qRT-PCR, RNA sequencing, and physiological assays, we demonstrated that overexpression of <i>OsPRX83</i> enhanced the osmotic and oxidative stress tolerance as compared to the wild-type and mutant seedlings, as evident from the higher survival rates, enhanced peroxidase (POD) and ascorbate peroxidase (APX) activities, and increased ABA sensitivity compared with mutants and wild-type plants. Transcriptome analysis further supported the involvement of <i>OsPRX83</i> in the ROS scavenging, by modulating the expression of <i>OsDREB1B</i>, <i>OsDREB1E</i>, <i>OsDREB1F</i>, <i>OsDREB1G</i> in response to osmotic treatment. In summary, our study suggests that <i>OsPRX83</i> plays a pivotal role in enhancing stress tolerance in rice through ABA-dependent pathways and ROS scavenging. Therefore, this study elucidates the function of a novel abiotic stress response gene in rice, thereby may contribute to a new genetic engineering resource for engineering drought-resistant rice varieties.植物III类过氧化物酶（Class III peroxidases）在调控根毛生长、花药发育以及非生物与生物胁迫响应过程中具有多样的生物学功能。然而，其在水稻中的非生物胁迫响应机制仍有待阐明。本研究鉴定得到一个过氧化物酶前体基因OsPRX83，并探究了其在提升水稻渗透胁迫耐受性中的作用。我们通过过表达OsPRX83以及CRISPR-Cas9创制的突变株系，解析了OsPRX83在胁迫条件下的功能与表达模式。OsPRX83的表达可被过氧化氢（H₂O₂）、聚乙二醇（PEG）、氯化钠（NaCl）以及脱落酸（ABA）处理诱导。通过实时定量PCR（qRT-PCR）、RNA测序（RNA sequencing）与生理实验，我们证实：相较于野生型（wild-type）与突变体（mutant）幼苗，过表达OsPRX83可提升水稻的渗透与氧化胁迫耐受性，具体体现为更高的存活率、更强的过氧化物酶（peroxidase，POD）与抗坏血酸过氧化物酶（ascorbate peroxidase，APX）活性，以及相较于突变体与野生型植株更高的ABA敏感性。转录组分析进一步表明，OsPRX83可通过调控OsDREB1B、OsDREB1E、OsDREB1F以及OsDREB1G的表达以响应渗透胁迫，从而参与活性氧（reactive oxygen species，ROS）的清除过程。综上，本研究揭示OsPRX83通过依赖脱落酸的信号通路与活性氧清除机制，在提升水稻胁迫耐受性方面发挥关键作用。因此，本研究阐明了水稻中一类新型非生物胁迫响应基因的功能，可为培育抗旱水稻品种提供全新的基因工程资源。