Guangdong Provincial Key Laboratory of Plant Resource, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
Planta. 2012 Jun;235(6):1271-88. doi: 10.1007/s00425-011-1573-y. Epub 2011 Dec 14.
Annexins are multifunctional proteins characterized by their capacity to bind calcium ions and negatively charged lipids. Although there is increasing evidence implicating their importance in plant stress responses, their functions in seeds remain to be further studied. In this study, we identified a heat-induced annexin, NnANN1, from the embryonic axes of sacred lotus (Nelumbo nucifera Gaertn.) using comparative proteomics approach. Moreover, the expression of NnANN1 increased considerably in response to high-temperature treatment. Quantitative real-time PCR (qRT-PCR) revealed that the transcripts of NnANN1 were detected predominantly during seed development and germination in sacred lotus, implicating a role for NnANN1 in plant seeds. Ectopic expression of NnANN1 in Arabidopsis resulted in enhanced tolerance to heat stress in transgenic seeds. In addition, compared to the wild-type seeds, transgenic seeds ectopically expressing NnANN1 exhibited improved resistance to accelerated aging treatment used for assessing seed vigor. Furthermore, transgenic seeds showed enhanced peroxidase activities, accompanied with reduced lipid peroxidation and reduced ROS release levels compared to the wild-type seeds. Taken together, these results indicate that NnANN1 plays an important role in seed thermotolerance and germination vigor.
annexins 是一类多功能蛋白，其特征为能够结合钙离子和带负电荷的脂质。虽然越来越多的证据表明它们在植物应激反应中的重要性，但它们在种子中的功能仍有待进一步研究。在这项研究中，我们使用比较蛋白质组学方法从神圣莲花（Nelumbo nucifera Gaertn.）的胚胎轴中鉴定出一种热诱导 annexin，NnANN1。此外，NnANN1 的表达在高温处理下显著增加。实时定量 PCR (qRT-PCR) 显示，NnANN1 的转录本在神圣莲花的种子发育和萌发过程中主要被检测到，表明 NnANN1 在植物种子中发挥作用。NnANN1 在拟南芥中的异位表达导致转基因种子对热胁迫的耐受性增强。此外，与野生型种子相比，异位表达 NnANN1 的转基因种子对用于评估种子活力的加速老化处理表现出更好的抗性。此外，与野生型种子相比，转基因种子的过氧化物酶活性增强，脂质过氧化和 ROS 释放水平降低。综上所述，这些结果表明 NnANN1 在种子耐热性和萌发活力中发挥重要作用。
