LEPS2, a phosphorus starvation-induced novel acid phosphatase from tomato
LEPS2, a phosphorus starvation-induced novel acid phosphatase from tomato
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DOI：
10.1104/pp.125.2.728
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发表时间：
2001-02-01
期刊：
影响因子：
7.4
通讯作者：
Raghothama, KG
中科院分区：
文献类型：
--
作者：
Baldwin, JC;Karthikeyan, AS;Raghothama, KG
磷酸盐 (Pi) 是土壤中最难利用的植物营养素之一。大量的磷酸盐以有机形式结合在根际中。据推测，植物和微生物产生的磷酸酶可将有机磷转化为可被植物吸收的磷。在这项研究中，我们描述了代表酸性磷酸酶的新型番茄（Lycoersicon esculentum）磷酸盐饥饿诱导基因（LePS2）的分离和表征。 LePS2 是番茄小基因家族的成员。 cDNA 长 942 bp，包含编码 269 个氨基酸多肽的开放阅读框。 LePS2的氨基酸序列与鸡的磷酸酶具有显着的相似性。该肽的不同区域也与磷酸水解酶 HAD 和 DDDD 超家族的成员具有显着的同一性。在数据库中发现了许多 LePS2 的植物同源物。在缺乏 Pi 的情况下，LePS2 转录本在番茄植株和细胞培养物中被快速诱导。然而，当 Pi 存在时，感应是可抑制的。分根研究表明内部 Pi 水平调节 LePS2 的表达。 LePS2表达的增强是对Pi饥饿的特异性反应，并且不受其他营养物质饥饿或非生物胁迫的影响。细菌（大肠杆菌）表达的蛋白质对合成底物磷酸对硝基苯酯表现出磷酸酶活性。酶活性的最适 pH 值表明 LePS2 是一种酸性磷酸酶。
Phosphate (Pi) is one of the least available plant nutrients found in the soil. A significant amount of phosphate is bound in organic forms in the rhizosphere. Phosphatases produced by plants and microbes are presumed to convert organic phosphorus into available Pi, which is absorbed by plants. In this study we describe the isolation and characterization of a novel tomato (Lycoersicon esculentum) phosphate starvation-induced gene (LePS2) representing an acid phosphatase. LePS2 is a member of a small gene family in tomato. The cDNA is 942 bp long and contains an open reading frame encoding a 269-amino acid polypeptide. The amino acid sequence of LePS2 has a significant similarity with a phosphatase from chicken. Distinct regions of the peptide also share significant identity with the members of HAD and DDDD super families of phosphohydrolases. Many plant homologs of LePS2 are found in the databases. The LePS2 transcripts are induced rapidly in tomato plant and cell culture in the absence of Pi. However, the induction is repressible in the presence of Pi. Divided root studies indicate that internal Pi levels regulate the expression of LePS2. The enhanced expression of LePS2 is a specific response to Pi starvation, and it is not affected by starvation of other nutrients or abiotic stresses. The bacterially (Escherichia coli) expressed protein exhibits phosphatase activity against the synthetic substrate p-nitrophenyl phosphate. The pH optimum of the enzyme activity suggests that LePS2 is an acid phosphatase.