DIVERSITY OF RHIZOBIA NODULATING PHASEOLUS-VULGALIS L IN 2 KENYAN SOILS WITH CONTRASTING PHS
DIVERSITY OF RHIZOBIA NODULATING PHASEOLUS-VULGALIS L IN 2 KENYAN SOILS WITH CONTRASTING PHS
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DOI：
10.1128/aem.61.11.4016-4021.1995
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发表时间：
1995-11-01
影响因子：
4.4
通讯作者：
GILLER, KE
中科院分区：
文献类型：
--
作者：
ANYANGO, B;WILSON, KJ;GILLER, KE
从 pH 值分别为 4.5 和 6.8 的两种肯尼亚土壤中分离出根瘤菌，并根据其结瘤和固氮寄主范围、菌落形态、限制性片段指纹以及 nifH 探针杂交进行了表征。两种土壤中的菜豆结瘤根瘤菌种群在数量和固氮效率方面相似，但在组成上明显不同。奈瓦沙土壤中的种群(pH 6.8) 主要是宿主范围内对普通 P. vulgaris 结瘤的特异性分离株；这些菌株都具有结构固氮酶基因 nifH 的多个拷贝，在大多数情况下为 4 个拷贝。来自该土壤的分离株中只有一个在 Laucaena leucocephala 上形成了有效的根瘤，并且该分离株仅具有一个 nifH 拷贝。相比之下，酸性 Daka-ini 土壤（pH 4.5）中的种群主要由具有单拷贝 nifH 的广泛宿主范围的分离株组成。来自 Daka-ini 土壤的分离株是 P. vulgaris 特有的，通常具有 3 个 nifH 拷贝，尽管一个分离株只有两个拷贝。这些根瘤菌分离株是肯尼亚土壤的本土菌株，但与之前描述的来自其他大陆的根瘤菌物种具有明显的相似性。
Rhizobia were isolated from two Kenyan soils with pHs of 4.5 and 6.8 and characterized on the basis of their host ranges for nodulation and nitrogen fixation, colony morphologies, restriction fragment fingerprints, and hybridization with a nifH probe, The populations of rhizobia nodulating Phaseolus vulgaris in the two soils were similar in numbers and in effectiveness of N-2 fixation but were markedly different in composition, The population in the Naivasha soil (pH 6.8) was dominated by isolates specific in host range for nodulation to P. vulgaris; these all had multiple copies, in most cases four, of the structural nitrogenase gene nifH, Only one of the isolates from this soil formed effective nodules on Laucaena leucocephala, and this isolate had only a single copy of nifH. By contrast, the population in the acid Daka-ini soil (pH 4.5) was composed largely of broad host-range isolates which had single copies of nifH. The isolates from the Daka-ini soil which were specific to P. vulgaris generally had three copies of nifH, although one isolate had only two copies, These rhizobial isolates are indigenous to Kenyan soils and yet have marked similarities to previously described Rhizobium species from other continents.