Rhizobium leguminosarum bv. viciae populations in soils with increasing heavy metal contamination:: abundance, plasmid profiles, diversity and metal tolerance
Rhizobium leguminosarum bv. viciae populations in soils with increasing heavy metal contamination:: abundance, plasmid profiles, diversity and metal tolerance
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DOI：
10.1016/s0038-0717(01)00210-3
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发表时间：
2002-04-01
影响因子：
9.7
通讯作者：
Giller, KE
中科院分区：
文献类型：
--
作者：
Lakzian, A;Murphy, P;Giller, KE
根瘤菌（Rhizobium leguminosartan bv.）在德国的布伦瑞克的一个长期的污水污泥实验中，对蚕豆进行了调查，这代表了金属污染的增加梯度。R.豆科植物湾随着Zn浓度的增加（从50到400 mg kg-1），蚕豆根尖细胞数从未污染区的10（5）cells g-1土壤减少到7到10（2）cells g-1土壤。用稀释的土壤接种于7个试验小区的蚕豆根瘤前，分离出根瘤菌（每小区约50个）。根瘤菌分离物具有3至9个质粒，其大小从约100至850 kb不等。虽然共鉴定出49个质粒图谱组，但使用扩增16 S和23 S rRNA基因之间的基因间间隔区（ITS）的引物进行的PCR-RFLP分析仅显示20个组。在未受污染的对照地块中发现了10个ITS群，但在污染最严重的地块中只发现了2个ITS群，在中度金属污染的地块中发现了6 ~ 8个ITS群。质粒图谱组的数量随着中度金属污染而增加，但当总锌浓度超过300 mg kg（-1）时，质粒图谱组的数量急剧减少。来自污染较轻地块的分离株仅含有3至5个质粒，而在金属浓度为200 mg kg（-1）或更高的地块中，含有7至9个质粒的分离株很丰富。而质粒图谱表明，随着金属污染的增加，菌株发生了相当大的变化，一个ITS组（组1）存在于所有地块。在对照区中，ITS组1的分离物仅含有3至4个质粒，但污染最严重的地块中的分离物含有8至9个质粒。随着金属污染的增加，属于ITS组1的菌株的金属耐受性显着增加，这与质粒携带数量的增加有关。然而，另一个ITS组（组2），其中只有三个大质粒，只存在于污染最严重的地块。从这个组的菌株有较低的耐受性，锌比许多菌株从未污染的地块。对这些菌株在重金属污染土壤中存活的可能机制进行了讨论。(C)2002爱思唯尔科技有限公司版权所有。
Populations of Rhizobium leguminosartan bv. viciae were investigated from plots of a long-term sewage Sludge experiment in Braunschweig Germany, which represented a gradient of increasing metal contamination. The number of R. leguminosarum be. viciae decreased from 10(5) cells g-(1) soil in uncontaminated plots to between 7 and 10(2) cells g(-1) soil with increasing Zn concentration (from 50 to 400 mg kg(-1)). Rhizobia were isolated front nodules of Vicia hirsuta inoculated with dilutions of soil front seven of the plots (similar to50 isolates per plot). The rhizobial isolates had between three and nine plasmids which varied in size from approximately 100 to 850 kb. Although a total of 49 plasmid profile groups were identified, PCR-RFLP analysis using primers which amplified an intergenic spacer (ITS) region between the 16S and 23S rRNA genes revealed only 20 groups. Ten ITS groups were found among the isolates from the uncontaminated control plot but only two groups were found in the most contaminated plot, and six to eight groups in the plots with intermediate metal contamination. Numbers of plasmid profile groups increased with moderate metal-contamination but were strongly reduced when total Zn concentrations exceeded 300 mg kg(-1). Isolates from the less contaminated plots had only three to five plasmids whereas isolates with seven to nine plasmids were abundant in the plots with metal concentrations of 200 mg kg(-1) or more. Whereas plasmid profiles indicated considerable changes in strains with increasing metal contamination, one ITS group (group 1) was present in all plots. Isolates from ITS group 1 contained only three to four plasmids in the control plots but those from the most contaminated plots had eight to nine plasmids. There was a marked increase in metal tolerance of isolates belonging to ITS group 1 as metal contamination increased, which was associated with the increase in the number of plasmids carried. However, another ITS group (group 2), which had only three large plasmids was present only in the most contaminated plot. Isolates from this group had less tolerance to Zn than many isolates from the uncontaminated plots. Possible mechanisms for the survival of these isolates in the metal contaminated soils are discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.