Isolation and characterization of cDNAs encoding xylogenesis-associated and wounding-induced ribonucleases in Zinnia elegans
Isolation and characterization of cDNAs encoding xylogenesis-associated and wounding-induced ribonucleases in Zinnia elegans
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DOI：
10.1007/bf00019005
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发表时间：
1996-02
影响因子：
5.1
通讯作者：
Z. Ye;D. Droste
中科院分区：
文献类型：
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作者：
Z. Ye;D. Droste
植物核糖核酸酶（RNase）功能的研究是复杂的组织中检测到的RNase活性的复杂配置文件。因此，分离单个RNA酶基因对于进一步理解每种RNA酶的功能将是期望的。在这里，我们描述了分离的cDNA编码的两个RNA酶，ZRNaseI和ZRNaseII，在分化的导管元件（TEs）诱导从分离的叶肉细胞的百日菊。ZRNaseI和ZRNaseII在氨基末端均显示出推定的分泌信号序列，预测成熟蛋白的分子量分别为24 247 Da和22 448 Da。DNA凝胶印迹分析表明，这两种RNase都由一个小基因家族编码。RNA凝胶印迹分析表明，ZRNase Ⅰ基因的表达与离体TE分化的后期有关，而ZRNase Ⅱ基因的表达主要是受胁迫诱导的。无论是RNase基因诱导响应磷酸盐饥饿，或在培养的叶肉细胞H2O2的挑战，或在叶片衰老。在幼叶中，ZRNaseI基因不受创伤诱导。而ZRNase Ⅱ基因在伤后6h才被明显诱导表达。组织印迹杂交结果表明，ZRNase Ⅰ基因的表达优先与正在分化的TE相关，而ZRNase Ⅱ mRNA在未损伤的Zinnia器官中未检测到。综上所述，结果表明，ZRNase Ⅰ基因在体外和植物体内的木质化过程中表达，而ZRNase Ⅱ基因主要是在对创伤的反应中被诱导。这些核糖核酸酶基因的鉴定提供了分子工具的解剖过程中的自溶木质部，解剖的作用核糖核酸酶在创伤反应。
The study of plant ribonuclease (RNase) functions is complicated by a complex profile of RNase activities detected in tissues. Thus, isolation of individual RNase genes will be desirable for the further understanding of function of each RNase. Here, we describe the isolation of cDNAs encoding two RNases, ZRNaseI and ZRNaseII, in differentiating tracheary elements (TEs) induced from isolated mesophyll cells ofZinnia elegans. Both the ZRNaseI and ZRNaseII exhibit putative secretion signal sequences at the amino-terminal ends with predicted molecular masses of 24 247 Da and 22 448 Da as mature proteins, respectively. DNA gel blot analysis showed that both RNases inZinniaappear to be encoded by a small gene family. RNA gel blot analysis showed that the expression of the ZRNaseI gene was associated with the late stage ofin vitroTE differentiation, whereas the ZRNaseII gene was mainly induced in response to stress. Neither RNase gene was induced in response to phosphate starvation, or to H2O2challenge in the cultured mesophyll cells, or to senescence in the leaves. In young leaves, the ZRNaseI gene was not induced in response to wounding. But the ZRNaseII gene was markedly induced by 6 h after wounding. Tissue print hybridization showed that the expression of the ZRNaseI gene was preferentially associated with the differentiating TEs inZinniastems, while the ZRNaseII mRNA was not detected in unwoundedZinniaorgans. Taken together, the results indicate that the ZRNaseI gene is expressed during the process of xylogenesis bothin vitroand in the plant, whereas the ZRNaseII gene is predominantly induced in response to wounding. The identification of these RNase genes provides molecular tools for the dissection of the process of autolysis during xylogenesis, and for the dissection of the role of RNase in wounding response.