Sulfate-reducing bacteria in rice field soil and on rice roots
Sulfate-reducing bacteria in rice field soil and on rice roots
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DOI：
10.1016/s0723-2020(99)80074-5
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发表时间：
1999-05-01
影响因子：
3.4
通讯作者：
Conrad, R
中科院分区：
文献类型：
--
作者：
Wind, T;Stubner, S;Conrad, R
检查了在淹水水稻土壤微观世界中生长的水稻植物表现出硫酸盐还原活性的能力。当在厌氧培养基中培养时，清洗后切下的稻根表现出硫酸盐还原潜力，表明硫酸盐还原细菌的存在。在双室（叶周和根际分开）中培养的水稻植株在缺氧根际区室中显示出潜在的硫酸盐还原率。当氧气通过植物的通气组织系统进入缺氧的根室时，这些速率下降，表明根部的硫酸盐还原剂被氧气部分抑制，或者硫酸盐通过还原的硫化合物的氧化而再生。硫酸盐还原剂对水稻根部的潜在活性与MPN计数一致，显示利用H-2的硫酸盐还原菌在根平面（4.1x10(7)g(-1)根鲜重）和邻近根际土壤（2.5x10(7)g(-1)土壤干重）中大量存在。另一方面，乙酸盐氧化性硫酸盐还原剂在未种植的大块土壤中显示出最高数量（1.9x10(6)g(-1)土壤干重）。从 MPN 系列的最高稀释度中分离出两种硫酸盐还原菌，并对其进行生理学和系统发育表征。以H-2为电子供体从根面分离得到的菌株F1-7b与脱硫弧菌科II亚组有关。菌株 EZ-2C2，从乙酸根平面分离，与 Desulforhabdus sp. 归为一组。和沃氏合成杆菌。其他硫酸盐还原菌菌株源自稻田土壤微观世界的大块土壤，并使用不同的电子供体进行分离。从这些分离株中，菌株R-AcA1、R-IbutA1、R-PimA1和R-AcetonA170是属于Desulfotomaculum属的革兰氏阳性细菌。其他分离株是脱硫弧菌科 II 亚组的成员（R-SucA1 和 R-LacA1），与脱硫杆菌属相关。 (菌株 BKA11)、Desulfobulbus (R-PropA1)，或聚集在 Desulfobotulus sapovorans 和 Desulfosarcina variabilis（R-ButA1 和 R-CaprA1）之间。
Rice plants that were grown in flooded rice soil microcosms were examined for their ability to exhibit sulfate reducing activity. Washed excised rice roots showed sulfate reduction potential when incubated in anaerobic medium indicating the presence of sulfate-reducing bacteria. Rice plants, that were incubated in a double-chamber (phylloshpere and rhizosphere separated), showed potential sulfate reduction rates in the anoxic rhizosphere compartment. These rates decreased when oxygen was allowed to penetrate through the aerenchyma system of the plants into the anoxic root compartment, indicating that sulfate reducers on the roots were partially inhibited by oxygen or that sulfate was regenerated by oxidation of reduced S-compounds. The potential activity of sulfate reducers on rice roots was consistent with MPN enumerations showing that H-2-utilizing sulfate-reducing bacteria were present in high numbers on the rhizoplane (4.1x10(7) g(-1) root fresh weight) and in the adjacent rhizosperic soil (2.5x10(7) g(-1) soil dry weight). Acetate-oxidizing sulfate reducers, on the other hand, showed highest numbers in the unplanted bulk soil (1.9x10(6) g(-1) soil dry weight). Two sulfate reducing bacteria were isolated from the highest dilutions of the MPN series and were characterized physiologically and phylogenetically. Strain F1-7b which was isolated from the rhizoplane with H-2 as electron donor was related to subgroup II of the family Desulfovibrionaceae. Strain EZ-2C2, isolated from the rhizoplane on acetate, grouped together with Desulforhabdus sp. and Syntrophobacter wolinii. Other strains of sulfate-reducing bacteria originated from bulk soil of rice soil microcosms and were isolated using different electron donors. From these isolates, strains R-AcA1, R-IbutA1, R-PimA1 and R-AcetonA170 were Gram-positive bacteria which were affiliated with the genus Desulfotomaculum. The other isolates were members of subgroup II of the Desulfovibrionaceae (R-SucA1 and R-LacA1), were related to Desulforhabdus sp. (strain BKA11), Desulfobulbus (R-PropA1), or clustered between Desulfobotulus sapovorans and Desulfosarcina variabilis (R-ButA1 and R-CaprA1).