Dynamic changes in the leaf proteome of a C3 xerophyte, Citrullus lanatus (wild watermelon), in response to water deficit
Dynamic changes in the leaf proteome of a C3 xerophyte, Citrullus lanatus (wild watermelon), in response to water deficit
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DOI：
10.1007/s00425-010-1341-4
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发表时间：
2011-05-01
期刊：
影响因子：
4.3
通讯作者：
Yokota, Akiho
中科院分区：
文献类型：
--
作者：
Akashi, Kinya;Yoshida, Kazuo;Yokota, Akiho
野生西瓜（Citrullus lanatus）是一种原产于非洲喀拉哈里沙漠的旱生植物。为了更好地了解这种植物抗旱性的分子机制，我们研究了蛋白质组响应缺水的变化。野生西瓜叶片在水分亏缺条件下表现出蒸腾作用下降，叶温随之升高。通过双向凝胶电泳对胁迫前后的蛋白质组进行比较，发现胁迫后40个蛋白质点的强度增加，11个蛋白质点的强度降低。通过质谱分析和数据库分析，我们确定了23个应激诱导蛋白和6个应激抑制蛋白。有趣的是，23种上调蛋白中有15种（占注释上调蛋白的65%）是热休克蛋白（HSP）。其中15个上调的热休克蛋白中有10个属于小热休克蛋白（small heat shock protein，sHSP）家族。其他应激诱导蛋白包括与抗氧化防御和碳水化合物代谢相关的蛋白。15个不同的cDNA序列编码的sHSP的特征在于从野生西瓜。代表性的sHSP基因的定量实时PCR分析显示，在水分亏缺下的叶片中强烈的转录上调。此外，免疫印迹分析证实，在水分亏缺下，sHSPs的蛋白质丰度大幅增加。总之，这些观察结果表明，野生西瓜的防御反应可能涉及精心策划的调节多种功能蛋白的细胞防御和代谢，其中热休克蛋白可能发挥了关键作用的保护植物水分亏缺在强光的存在下。
Wild watermelon (Citrullus lanatus) is a xerophyte native to the Kalahari Desert, Africa. To better understand the molecular mechanisms of drought resistance in this plant, we examined changes in the proteome in response to water deficit. Wild watermelon leaves showed decreased transpiration and a concomitant increase in leaf temperature under water deficit conditions. Comparison of the proteome of stressed plants with that of unstressed plants by two-dimensional gel electrophoresis revealed that the intensity of 40 spots increased in response to the stress, and the intensity of 11 spots decreased. We positively identified 23 stress-induced and 6 stress-repressed proteins by mass spectrometry and database analyses. Interestingly, 15 out of the 23 up-regulated proteins (65% of annotated up-regulated proteins) were heat shock proteins (HSPs). Especially, 10 out of the 15 up-regulated HSPs belonged to the small heat shock protein (sHSP) family. Other stress-induced proteins included those related to antioxidative defense and carbohydrate metabolism. Fifteen distinct cDNA sequences encoding the sHSP were characterized from wild watermelon. Quantitative real-time PCR analysis of the representative sHSP genes revealed strong transcriptional up-regulation in the leaves under water deficit. Moreover, immunoblot analysis confirmed that protein abundance of sHSPs was massively increased under water deficit. Overall, these observations suggest that the defense response of wild watermelon may involve orchestrated regulation of a diverse array of functional proteins related to cellular defense and metabolism, of which HSPs may play a pivotal role on the protection of the plant under water deficit in the presence of strong light.