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Production of solar driven gas-gas-converting denitrifying plants and their utilization for mitigation of air pollution

太阳能驱动的燃气-燃气转化脱硝装置的生产及其用于减轻空气污染的利用

基本信息

批准号：
13556002
负责人：
MORIKAWA Hiromichi
金额：
$ 8.96万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

项目摘要

It has been shown for the first time that the capability to convert nitrate (or nitrite) to N_2O is common in various plants with some exceptions. It is also suggested that NO_2 can also be utilized as substrate in the "denitrification" process of plants. There was more than a 58-fold variation in the "N_2O emission" in the 17 plant taxa studied. A negative correlation was obtained for the N_2O emission and NO_2 assimilation. This is the first report that there is a competitive interaction between the activities of plants to assimilate and "dissimilate" nitrogen in plants.The nosZ gene from Pseudomonas stutzeri, a denitrifier, encoding nitrous oxide reductase (N_2OR) was fused to the CaMV 35S promoter and the resulting expression cassette (pIGnosZ) was introduced to roots of Arabidopsis thaliana ecotype C24 by Agrobacterium method. Transgenic plants were selected for hygromycin resistance. Expression of nosZ gene was shown by western blotting analysis using anti-N_2OR antibody. The result indicated that bacterial N_2OR gene was transcribed and translated in plants. The N_2OR enzyme activity in the extracts of T_2 plants was assayed using benzyl viologen as electron donor. To date no positive results showing the enzyme activity in transgenic plants have been obtained.Arabidopsis thaliana and rice genomes have been launched, taking this advantage homology searches for plant genes related to bacterial or fungal denitrification system were done. However, no completely sequenced genes, at least in Arabidopsis and rice genomes, were homologous to those for the gas-gas converting steps of the bacterial or fungal denitrification pathways.Phylogeny and bioinformatics studies revealed that the fungi Fusarium oxysporum and Cylidrocarpon tonkinense cytochrome P-450 (P-450nor) are phylogenetically related to Arabidopsis COX6B and to rice COX6B.

首次证明，将硝酸盐(或亚硝酸盐)转化为N_2O的能力在各种植物中是常见的，但也有一些例外。在植物的“反硝化”过程中，也可以利用NO2作为底物。在所研究的17种植物中，“N_2O排放”的差异超过58倍。N2O排放与NO2同化呈负相关。首次报道了植物同化和“异化”氮素之间存在竞争性相互作用。利用农杆菌法将编码一氧化二氮还原酶(N_2OR)的反硝化假单胞菌nosZ基因与CaMV 35S启动子融合，构建表达盒pIGnosZ，并将其导入拟南芥生态型C24。对转基因植株进行潮霉素抗性筛选。用抗N2OR抗体进行免疫印迹检测nosZ基因的表达。结果表明，细菌N_2OR基因已在植物中转录和翻译。以苯基紫精为电子供体，测定了T2植物提取物中N_2OR酶的活性。到目前为止，还没有获得转基因植物中酶活性的阳性结果。拟南芥和水稻基因组已经启动，利用这一优势，对与细菌或真菌反硝化系统相关的植物基因进行了同源搜索。然而，至少在拟南芥和水稻基因组中，没有完全测序的基因与细菌或真菌反硝化途径中气体-气体转化步骤的基因同源。系统发育和生物信息学研究表明，真菌尖孢镰刀菌和环孢霉细胞色素P-450(P-450nor)与拟南芥COX6B和水稻COX6B具有亲缘关系。