Effect of Flooding and the nosZ Gene in Bradyrhizobia on Bradyrhizobial Community Structure in the Soil.
Effect of Flooding and the nosZ Gene in Bradyrhizobia on Bradyrhizobial Community Structure in the Soil.
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DOI：
10.1264/jsme2.me16132
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发表时间：
2017-06-24
影响因子：
2.2
通讯作者：
Yamamoto A
中科院分区：
文献类型：
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作者：
Saeki Y;Nakamura M;Mason MLT;Yano T;Shiro S;Sameshima-Saito R;Itakura M;Minamisawa K;Yamamoto A
我们研究了水分状况（淹水或非淹水）和慢生型根瘤菌中nosZ基因的存在对慢生型根瘤菌群落结构的影响，在析因实验中，使用微宇宙培养考察了三种温度水平（20°C，25°C和30°C）和两种土壤类型（干旱土和灰色低地土壤）。所有微宇宙均接种慢生根瘤菌USDA 6 T，B。japonicum USDA 123和B. elkanii USDA 76 T，其不具有nosZ基因，然后一半接受B。diazoefficiens USDA 110 Twt（野生型的wt），另一半接受B。diazoefficiens USDA 110 ΔnosZ. USDA 110 Twt具有编码N2 O还原酶的nosZ基因;而110ΔnosZ则没有。通过变性梯度凝胶电泳和图像分析研究了孵育30天和60天后群落结构的变化。USDA 6 T和76 T菌株在非淹水土壤中略有增加，无论哪种USDA 110 T菌株存在。在具有USDA 110 Twt菌株的淹水微宇宙中，USDA 110 Twt成为优势，而在具有USDA 110 ΔnosZ的微宇宙中，群落结构发生了与非淹水微宇宙相似的变化。这些结果表明，拥有nosZ基因赋予B竞争优势。重氮菌USDA 110 T。本文证明了B.土壤根瘤菌群中的diazoefficiens USDA 110 Twt可能会通过洪水或水涝系统（如水稻-大豆轮作）的周期来增强，因为它似乎具有在中度厌氧土壤中茁壮成长的能力。
We investigated the effects of the water status (flooded or non-flooded) and presence of the nosZ gene in bradyrhizobia on the bradyrhizobial community structure in a factorial experiment that examined three temperature levels (20°C, 25°C, and 30°C) and two soil types (andosol and gray lowland soil) using microcosm incubations. All microcosms were inoculated with Bradyrhizobium japonicum USDA6T, B. japonicum USDA123, and B. elkanii USDA76T, which do not possess the nosZ gene, and then half received B. diazoefficiens USDA110Twt (wt for the wild-type) and the other half received B. diazoefficiens USDA110ΔnosZ. USDA110Twt possesses the nosZ gene, which encodes N2O reductase; 110ΔnosZ, a mutant variant, does not. Changes in the community structure after 30- and 60-d incubations were investigated by denaturing-gradient gel electrophoresis and an image analysis. USDA6T and 76T strains slightly increased in non-flooded soil regardless of which USDA110T strain was present. In flooded microcosms with the USDA110Twt strain, USDA110Twt became dominant, whereas in microcosms with the USDA110ΔnosZ, a similar change in the community structure occurred to that in non-flooded microcosms. These results suggest that possession of the nosZ gene confers a competitive advantage to B. diazoefficiens USDA110T in flooded soil. We herein demonstrated that the dominance of B. diazoefficiens USDA110Twt within the soil bradyrhizobial population may be enhanced by periods of flooding or waterlogging systems such as paddy–soybean rotations because it appears to have the ability to thrive in moderately anaerobic soil.