A Novel Gene, OZONE-RESPONSIVE APOPLASTIC PROTEIN1, Enhances Cell Death in Ozone Stress in Rice1
A Novel Gene, OZONE-RESPONSIVE APOPLASTIC PROTEIN1, Enhances Cell Death in Ozone Stress in Rice1
复制标题
一种新基因，臭氧响应性质外蛋白 1，可增强水稻在臭氧胁迫下的细胞死亡 1
DOI：
10.1104/pp.15.00956
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发表时间：
2015
期刊：
影响因子：
7.4
通讯作者：
Frei M
中科院分区：
文献类型：
--
作者：
Ueda Y;Siddique S;Frei M
一种新的蛋白质——臭氧响应性质外蛋白1（OsORAP1）被表征，该蛋白质之前被认为是OzT9的候选基因，OzT9是水稻（Oryza sativa）耐臭氧胁迫的数量性状基因座。 OsORAP1 的序列与抗坏血酸氧化酶 (AO) 蛋白的序列相似。它位于质外体中，如 OsORAP1/绿色荧光蛋白融合构建体在烟草表皮和叶肉细胞中的瞬时表达所示，但不具有 AO 活性，如背景 AO 活性降低的拟南芥 (Arabidopsis thaliana) 突变体中 OsORAP1 的异源表达所示。 OsORAP1 基因敲除水稻品系表现出对臭氧胁迫的耐受性增强（120 nL L−1 平均日间浓度，20 d），这通过叶子可见症状（即细胞死亡）的形成减少、脂质过氧化减少和 NADPH 氧化酶活性降低来证明，这表明活性氧的主动产生减少。相比之下，臭氧对叶绿素含量的影响在品系之间没有显着差异。这些观察结果表明，OsORAP1 在臭氧应激下特异性诱导细胞死亡。敲除株系中茉莉酸反应基因的表达显着增强，表明茉莉酸途径参与症状缓解。序列分析揭示了OsORAP1启动子区在臭氧敏感品种Nipponbare和耐臭氧品种Kasalath（OzT9供体品种）之间存在广泛的多态性，这可能是先前报道的OsORAP1差异调节的原因。这些证据表明，OsORAP1 增强了臭氧胁迫下的细胞死亡，其表达水平可以解释先前报道的数量性状基因座的影响。
A novel protein, OZONE-RESPONSIVE APOPLASTIC PROTEIN1 (OsORAP1), was characterized, which was previously suggested as a candidate gene underlyingOzT9, a quantitative trait locus for ozone stress tolerance in rice (Oryza sativa). The sequence of OsORAP1 was similar to that of ASCORBATE OXIDASE (AO) proteins. It was localized in the apoplast, as shown by transient expression of an OsORAP1/green fluorescent protein fusion construct inNicotiana benthamianaleaf epidermal and mesophyll cells, but did not possess AO activity, as shown by heterologous expression of OsORAP1 in Arabidopsis (Arabidopsis thaliana) mutants with reduced background AO activity. A knockout rice line ofOsORAP1showed enhanced tolerance to ozone stress (120 nL L−1average daytime concentration, 20 d), as demonstrated by less formation of leaf visible symptoms (i.e. cell death), less lipid peroxidation, and lower NADPH oxidase activity, indicating reduced active production of reactive oxygen species. In contrast, the effect of ozone on chlorophyll content was not significantly different among the lines. These observations suggested that OsORAP1 specifically induced cell death in ozone stress. Significantly enhanced expression of jasmonic acid-responsive genes in the knockout line implied the involvement of the jasmonic acid pathway in symptom mitigation. Sequence analysis revealed extensive polymorphisms in the promoter region ofOsORAP1between the ozone-susceptible cv Nipponbare and the ozone-tolerant cv Kasalath, theOzT9donor variety, which could be responsible for the differential regulation ofOsORAP1reported earlier. These pieces of evidence suggested that OsORAP1 enhanced cell death in ozone stress, and its expression levels could explain the effect of a previously reported quantitative trait locus.