木麻黄根瘤内生弗兰克氏菌的反硝化作用  

Denitrification process of Casuarina root nodule endophyte Frankia

作　　者：陈惠 朱成[1] 林红莲 马红亮 尹云锋[1] 高人[1,2] CHEN Hui;ZHU Cheng;LIN Hong-lian;MA Hongliang;YIN Yunfeng;GAO Ren(School of Geographical Sciences,Fujian Normal University,Fuzhou 350007,China;Fujian Provincial Key Laboratory of Plant Ecophysiology,Fujian Normal University,Fuzhou 350007,China)

机构地区：[1]福建师范大学地理科学学院,福州350007 [2]福建师范大学福建省植物生理生态重点实验室,福州350007

出　　处：《应用生态学报》2023年第4期1109-1116,共8页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金项目(32171758,31570607);福建省自然科学基金项目(2019J01282)。

摘　　要：为了解非豆科植物共生固氮菌弗兰克氏菌的反硝化作用特点以及作为N_(2)O源汇的能力,采用切片法分离并纯培养木麻黄根瘤内生弗兰克氏菌,探究NO_(3)^(-)添加下弗兰克氏菌的反硝化作用过程。结果表明:在厌氧培养条件下添加NO_(3)^(-)后,NO_(3)^(-)浓度随时间的增加而降低,26 h后趋于平稳;而NO_(2)^(-)和N_(2)O的浓度随着时间的增加先升高后降低。在培养第26、54和98小时均检测到关键反硝化基因和固氮酶基因。基因之间的丰度差异显著,且随时间的变化不同步。冗余分析表明,以NO_(3)^(-)、NO_(2)^(-)和N_(2)O浓度为解释变量,前2个排序轴总共解释了反硝化及固氮酶基因丰度总变异的81.9%。弗兰克氏菌在厌氧条件下具有反硝化作用,检测到系列反硝化基因,包括N_(2)O还原酶基因(nosZ),表明该弗兰克氏菌具备完全的反硝化途径,具有还原吸收N_(2)O的能力。To examine the characteristic of denitrification in Frankia,a symbiotic nitrogen-fixing microbe associated with non-leguminous plants,and its role as a N_(2)O source or sink,Casuarina root nodule endophyte Frankia was isolated using sectioning method,which was then purely cultured to investigate the denitrification process under NO_(3)^(-)addition.The results showed that after addition of NO_(3)^(-)to the medium under anaerobic condition,the concentration of NO_(3)^(-)decreased with time,while the concentrations of NO_(2)^(-)and N_(2)O initially increased and then decreased over time.Key denitrification genes and nitrogenase gene were detected at 26 h,54 h and 98 h during incubation.Abundances of these genes significantly differed among each other,and their dynamics were asynchronous.Redundancy analysis of the effect of NO_(3)^(-),NO_(2)^(-),N_(2)O concentrations on abundances of denitrification genes and nitrogenase gene indicated that 81.9%of the total variation in gene abundances could be explained by the first two axes.Frankia had a denitrifying activity under anaerobic condition,with denitrification genes,including nitrous oxide reductase gene(nosZ),being identified.Our results suggested that Frankia possessed a complete denitrification pathway and the ability of N_(2)O reduction under anaerobic condition.

关 键 词：木麻黄 弗兰克氏菌 纯培养 功能基因 反硝化作用 

分 类 号：S792.93[农业科学—林木遗传育种]