Differential expression pattern of an acidic 9/13-lipoxygenase in flower opening and senescence and in leaf response to phloem feeders in the tea plant.
Differential expression pattern of an acidic 9/13-lipoxygenase in flower opening and senescence and in leaf response to phloem feeders in the tea plant.
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茶树花开放和衰老过程中酸性 9/13-脂氧合酶的差异表达模式以及叶对韧皮部饲养层的反应
DOI：
10.1186/1471-2229-10-228
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发表时间：
2010-10-25
影响因子：
5.3
通讯作者：
Han B
中科院分区：
文献类型：
--
作者：
Liu S;Han B
脂氧合酶(Lipoxygenase，LOXs)是一大类植物酶，能催化游离多不饱和脂肪酸的氢过氧化反应生成多种生物活性化合物，统称为植物氧合脂。虽然在一年生草本植物中已经发现了多种LOXs亚型，但多年生木本植物中编码这些酶的基因还没有得到那么多的关注。在茶树(Camellia sinensis(L.)没有分离到任何类型的LOX基因，其在茶树发育、衰老和防御反应中的可能作用尚不清楚。本研究描述了第一个茶树LOX亚型CsLOX1的分离、鉴定和表达，并试图阐明其在植物防御反应以及开花和衰老过程中的表达模式。结果根据与植物LOXs氨基酸序列的相似性，在茶树中鉴定出一个LOX，命名为CsLOX1，编码一个由861个氨基酸组成的多肽，分子量为97.8 kDa。酵母异源表达分析表明，CsLOX1蛋白具有双重位置特异性，因为它以等比例释放C-9和C-13氧化产物，因此命名为9/13-CsLOX1。纯化的重组CsLOX1蛋白在pH 3.6和25℃时具有最高的催化活性。实时定量PCR分析表明，CsLOX1转录本主要在花中检测到，在花瓣衰老过程中表达上调，在花蕾开放时表达下调。在叶片中，该基因在伤害后或在茉莉酸甲酯(MeJA)处理后上调，但水杨酸(SA)不诱导这种反应。茶树绿叶蝉取食后，CsLOX1基因也被快速高效地诱导表达，而茶蚜Toxoptera aurantii取食后，则呈现诱导和抑制交替的模式。结论对茶树LOX基因的分离和表达分析表明，酸性CsLOX1及其初级和末端产物在调控植物对韧皮部取食者的防御反应和花朵衰老相关的细胞死亡中起重要作用。
BackgroundLipoxygenase (LOXs) is a large family of plant enzymes that catalyse the hydroperoxidation of free polyunsaturated fatty acids into diverse biologically active compounds, collectively named phyto-oxylipins. Although multiple isoforms of LOXs have been identified in a wide range of annual herbaceous plants, the genes encoding these enzymes in perennial woody plants have not received as much attention. InCamellia sinensis(L.) O. Kuntze, no LOX gene of any type has been isolated, and its possible role in tea plant development, senescence, and defence reaction remains unknown. The present study describes the isolation, characterization, and expression of the first tea plant LOX isoform, namelyCsLOX1, and seeks to clarify the pattern of its expression in the plant's defence response as well as in flower opening and senescence.ResultsBased on amino acid sequence similarity to plant LOXs, a LOX was identified in tea plant and namedCsLOX1, which encodes a polypeptide comprising 861 amino acids and has a molecular mass of 97.8 kDa. Heterologous expression in yeast analysis showed that CsLOX1 protein conferred a dual positional specificity since it released both C-9 and C-13 oxidized products in equal proportion and hence was named 9/13-CsLOX1. The purified recombinant CsLOX1 protein exhibited optimum catalytic activity at pH 3.6 and 25°C. Real-time quantitative PCR analysis showed thatCsLOX1transcripts were detected predominantly in flowers, up-regulated during petal senescence, and down-regulated during flower bud opening. In leaves, the gene was up-regulated following injury or when treated with methyl jasmonate (MeJA), but salicylic acid (SA) did not induce such response. The gene was also rapidly and highly induced following feeding by the tea green leafhopperEmpoasca vitis, whereas feeding by the tea aphidToxoptera aurantiiresulted in a pattern of alternating induction and suppression.ConclusionsAnalysis of the isolation and expression of theLOXgene in tea plant indicates that the acidic CsLOX1 together with its primary and end products plays an important role in regulating cell death related to flower senescence and the JA-related defensive reaction of the plant to phloem-feeders.
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影响因子：
56.9
作者：
Kessler, A;Halitschke, R;Baldwin, IT
通讯作者：
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影响因子：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
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影响因子：
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