Abstract As tropospheric ozone is increasingly posing Asian rice production at risk, the breeding of novel adapted varieties is required. In this study, we investigated sequence polymorphisms in the OZONE RESPONSIVE APOPLASTIC PROTEIN1 (OsORAP1) gene in eighteen Asian rice varieties, and how these affect ozone tolerance. Sequencing of 5′-UTR and promoter regions of OsORAP1 demonstrated that different varieties fell into two distinct clades referred to as the Nipponbare-type and the Kasalath-type allele. When exposed to elevated ozone (100 ppb, nine days, seven hours per day) the group of varieties carrying the Nipponbare-type allele showed a significantly higher level of foliar symptom formation, lipid peroxidation, and shoot biomass loss. Also, transcriptional regulatory patterns of the OsORAP1 gene differed between the two allele classes, as the Nipponbare-types exhibited significantly higher induction of OsORAP1 expression in ozone stress. Using transcriptomic data we identified cis-elements enriched in ozone-inducible genes and analyzed their presence in the 5′-UTR and promoter region of OsORAP1. We found that cis-elements recognized by WOX and ZF-HD type transcription factors occurred only in the Nipponbare-types. In summary, this study provides strong correlative evidence that OsORAP1 is an important regulator of ozone response and tolerance in Asian rice.

中文翻译：

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OsORAP1 基因座的自然序列变异是亚洲水稻耐臭氧性的标志

摘要 随着对流层臭氧日益威胁亚洲水稻生产，需要培育新的适应品种。在这项研究中，我们调查了 18 个亚洲水稻品种中 OZONE RESPONSIVE APOPLASTIC PROTEIN1 (OsORAP1) 基因的序列多态性，以及它们如何影响臭氧耐受性。OsORAP1 的 5'-UTR 和启动子区域的测序表明，不同的品种分为两个不同的进化枝，称为 Nipponbare 型和 Kasalath 型等位基因。当暴露于升高的臭氧（100 ppb，每天 9 天，每天 7 小时）时，携带日本晴型等位基因的品种组表现出显着更高水平的叶症状形成、脂质过氧化和枝条生物量损失。此外，OsORAP1 基因的转录调控模式在两个等位基因类别之间有所不同，因为日本晴型在臭氧胁迫中表现出显着更高的 OsORAP1 表达诱导。使用转录组数据，我们鉴定了富含臭氧诱导基因的顺式元件，并分析了它们在 OsORAP1 的 5'-UTR 和启动子区域中的存在。我们发现 WOX 和 ZF-HD 型转录因子识别的顺式元件仅出现在 Nipponbare 型中。总之，本研究提供了强有力的相关证据，表明 OsORAP1 是亚洲水稻臭氧响应和耐受性的重要调节剂。我们发现 WOX 和 ZF-HD 型转录因子识别的顺式元件仅出现在 Nipponbare 型中。总之，本研究提供了强有力的相关证据，表明 OsORAP1 是亚洲水稻臭氧响应和耐受性的重要调节剂。我们发现 WOX 和 ZF-HD 型转录因子识别的顺式元件仅出现在 Nipponbare 型中。总之，本研究提供了强有力的相关证据，表明 OsORAP1 是亚洲水稻臭氧响应和耐受性的重要调节剂。