Alternate wetting and drying irrigation (AWD) benefits root iron plaque (IP) formation and nutrient uptake, but the underlying mechanism is unclear. RNA-sequencing, histochemical staining, confocal laser microscopy, and transgenic techniques were used to evaluate the contributions of ionic-bonded cell-wall-located class III peroxidases (iPrxs) and hydrogen peroxide (H2O2) to IP formation in rice (Oryza sativa) under AWD. AWD significantly enhanced iPrx activity and expression of OsPrx24, a gene encoding iPrx, accompanied by elevated H2O2 accumulation and IP formation. Microscopic analysis indicated that OsPrx24 was mainly expressed in root epidermis, where H2O2 accumulation and IP precipitation also occurred. In an OsPrx24-overexpression line (OsPrx24-OX), the H2O2 concentration was 28.2% lower, and IP formation was 42.6% higher than in the wild type (WT). Treatment with both an iPrx inhibitor and an H2O2 scavenger reduced the IP content, but it was higher in OsPrx24-OX than in the WT under these treatment conditions. Phosphorus concentrations were higher and more IP was found in the roots of OsPrx24-OX than the WT. The results imply that OsPrx24 participates in IP formation by regulating iPrx activity and H2O2 concentration under AWD. The results enhance our understanding of IP formation and nutrient uptake in rice.

中文翻译：

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III类过氧化物酶基因OsPrx24对干湿交替灌溉下水稻根部铁斑形成和磷吸收很重要

交替干湿灌溉 (AWD) 有利于根铁斑块 (IP) 的形成和养分吸收，但潜在机制尚不清楚。RNA测序、组织化学染色、共聚焦激光显微镜和转基因技术用于评估离子键合细胞壁III类过氧化物酶（iPrxs）和过氧化氢（H2O2）对水稻（Oryza sativa）IP形成的贡献在全轮驱动下。AWD 显着增强了 iPrx 活性和 OsPrx24（一种编码 iPrx 的基因）的表达，伴随着 H2O2 积累和 IP 形成的增加。显微分析表明，OsPrx24 主要在根表皮中表达，在此也发生 H2O2 积累和 IP 沉淀。在 OsPrx24 过表达系 (OsPrx24-OX) 中，H2O2 浓度低 28.2%，IP 形成为 42。比野生型 (WT) 高 6%。用 iPrx 抑制剂和 H2O2 清除剂处理降低了 IP 含量，但在这些处理条件下，OsPrx24-OX 中的 IP 含量高于 WT。与 WT 相比，在 OsPrx24-OX 的根中发现磷浓度更高，IP 也更多。结果表明 OsPrx24 通过调节 AWD 下的 iPrx 活性和 H2O2 浓度参与 IP 形成。结果增强了我们对水稻 IP 形成和养分吸收的理解。结果表明 OsPrx24 通过调节 AWD 下的 iPrx 活性和 H2O2 浓度参与 IP 形成。结果增强了我们对水稻 IP 形成和养分吸收的理解。结果表明 OsPrx24 通过调节 AWD 下的 iPrx 活性和 H2O2 浓度参与 IP 形成。结果增强了我们对水稻 IP 形成和养分吸收的理解。