Functional analysis of cold-inducible cDNA clones in the legume Ammopiptanthus mongolicus.
Functional analysis of cold-inducible cDNA clones in the legume Ammopiptanthus mongolicus.
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发表时间：
2005-07
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通讯作者：
Mei-qin Liu;Xin Shen;W. Yin;Cunfu Lu
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作者：
Mei-qin Liu;Xin Shen;W. Yin;Cunfu Lu
沙冬青是我国西北沙区阿拉善沙漠特有的唯一常绿阔叶灌木，能在-30℃甚至更低的冬季生存。开发了一种改良的固相消减杂交技术来分离和筛选在冷处理的蒙古沙幼苗中转录本增加的cDNA。对筛选的克隆进行序列分析表明，11个克隆具有编码区，其中4个含有完整的开放阅读框。 11 个克隆中有 9 个与 GenBank 数据库中发现的基因具有不同程度的同源性，另外两个是未识别的序列。序列数据进一步揭示，这些积累的转录本编码： 三种低分子量蛋白（一种胚胎发生晚期蛋白和两种冷适应响应蛋白）；两种光合作用相关蛋白（光系统 I 亚基 II 前体 (PsaD) 和光系统 II 释氧复合物 33kDa 亚基 OEC33）；蛋白酶抑制剂；腺苷三磷酸酶和 14-3-3 相关蛋白。对这些蛋白的功能分析表明，低分子量蛋白与细胞质保水能力有关，光合作用相关蛋白参与光合机构抵抗光抑制的调节； 14-3-3相关蛋白可以与三磷酸腺苷相互作用，增强ATP酶活性和能量代谢，蛋白酶抑制剂参与预防活性氧引起的不必要的细胞死亡。我们认为，蒙古沙蚕低光强度的冷驯化是低温、光、能量和信号之间比之前假设的更复杂的相互作用。
Ammopiptanthus mongolicus is the only evergreen broadleaf shrub endemic to the Alashan desert, northwest sand area of China, and can survive -30 degrees C or an even lower temperature in winter. A modified solid-phase subtraction hybridization technique was developed to isolate and screen cDNAs whose transcripts increased in cold-treated A. mongolicus seedlings. Sequence analysis of the screened clones indicated that 11 clones had coding regions, with four of them containing a complete open reading frame. Nine of the 11 clones shared various degrees of homology with the genes found in the GenBank database and the other two were unidentified sequences. Sequence data further revealed that these accumulated transcripts encoded: three low molecular weight proteins (a late-embryogenesis protein and two cold acclimation responsive proteins); two photosynthesis-related proteins, (photosystem I subunit II precursor (PsaD) and photosystem II oxygen-evolving complex 33kDa subunit OEC33); a protease inhibitor; an adenosine triphosphatase and a 14-3-3 related protein. Analysis of the function of these proteins indicated that the low molecular weight proteins were associated with water holding ability of cytoplasm, photosynthesis-related proteins participated in the adjustments of photosynthetic apparatus to resist photoinhibition; 14-3-3 related protein could interact with adenosine triphosphatase to enhance ATPase activity and energy metabolism, and protease inhibitor is involved in the prevention of unwanted cell death caused by reactive oxygen species. We suggest that cold acclimation with low light intensity in A. mongolicus is a more complex interaction of low temperature, light, energy and signal than that assumed previously.