Denitrification by the fungus Fusarium oxysporum involves NADH-Nitrate reductase
Denitrification by the fungus Fusarium oxysporum involves NADH-Nitrate reductase
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DOI：
10.1271/bbb.70538
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发表时间：
2008-02-01
影响因子：
1.6
通讯作者：
Takaya, Naoki
中科院分区：
文献类型：
--
作者：
Fuji, Tatsuya;Takaya, Naoki
镰刀菌JCM11502表现出反硝化（硝态氮）呼吸机制，并能在氧（02）限制下繁殖。在反硝化的初始阶段，真菌将NO3-还原为亚硝酸盐。本研究克隆了尖孢菌JCM11502中NADH-NO3-还原酶（NADH-Nar） （niaD）的编码基因。niaD基因补充了突变菌株M10的NO3-同化缺陷，表明该真菌通过NADH-Nar活性减少NO3-，并像其他真菌一样对其进行同化。我们发现，与有氧条件相比，在o -2限制反硝化条件下，niaD的转录和NADH-Nar活性的产生得到了增强。菌株M10产生的NADH-Nar活性和反硝化产物低于野生型菌株。在突变体中引入niaD也恢复了这些缺陷，表明niaD参与了反硝化作用。这些结果表明，除泛醇- nar机制外，真菌还通过NADH-Nar活性反硝化NO3-。
Fusarium oxysporum JCM11502 expresses a denitrifying (nitrate (NO3-)-respiring) mechanism and can thrive under oxygen (02) limitation. The fungus reduces NO3- to nitrite at the initial step of denitrification. In this study, we cloned the gene coding NADH-NO3- reductase (NADH-Nar) (niaD) from F. oxysporum JCM11502. The niaD gene complemented the defective NO3- assimilation by mutant strain M10, indicating that the fungus reduced NO3- through NADH-Nar activity and assimilated it like other fungi. We found that the transcription of niaD and the production of NADH-Nar activity were enhanced under O-2-limited denitrifying conditions relative to aerobic conditions. Strain M10 produced less NADH-Nar activity and less denitrified product than the wild-type strain. Introducing niaD into the mutant also restored these defects, indicating that niaD is involved in denitrification. These results indicate that the fungus denitrified NO3- through NADH-Nar activity in addition to the ubiquinol-Nar mechanism.