Horizontal transfer of genetic determinants for degradation of phenol between the bacteria living in plant and its rhizosphere
Horizontal transfer of genetic determinants for degradation of phenol between the bacteria living in plant and its rhizosphere
复制标题
DOI：
10.1007/s00253-007-1187-2
复制
发表时间：
2007-10
影响因子：
5
通讯作者：
Yujing Wang;M. Xiao;Xiaolu Geng;Jiaying Liu;Jun Chen
中科院分区：
文献类型：
--
作者：
Yujing Wang;M. Xiao;Xiaolu Geng;Jiaying Liu;Jun Chen
苯酚和其他单环芳香族化合物（MAC）是高度水溶性和挥发性的污染物，植物无法完全降解。具有MAC降解能力的植物内生细菌有利于污染土壤的植物修复，有利于植物在污染土壤中的存活。分别从玉米根组织和化工厂附近的玉米根际分离到内生细菌菌株FX 1-FX 3和根际细菌菌株FX 0、FX 4和FX 5。菌株FX 1-FX 5能在苯酚上生长并降低苯酚浓度，而菌株FX 0不能。菌株FX 1、FX 3和FX 4被鉴定为荧光假单胞菌（Pseudomonasfluorescens），FX 0、FX 2和FX 5被鉴定为洋葱伯克霍尔德菌（Burkholderiacepacia）。从菌株FX 1-FX 5中分离的质粒被发现具有相似的性状，并且装载有编码邻苯二酚2，3-双加氧酶（C23 O）的基因，邻苯二酚2，3-双加氧酶是苯酚降解途径中的关键酶。序列比对和系统发育分析表明，C23 O基因可能发生了原位水平转移。通过接合交配实验证明了C23 O基因在植物内生菌和根际细菌之间的水平转移，获得了携带C23 O基因质粒的接合子，能够在苯酚上生长并降解苯酚。
Phenol and other monocyclic aromatic compounds (MACs) are highly water-soluble and volatile pollutants that plants are unable to completely degrade. Endophytic bacteria with MAC-degrading ability will facilitate phytoremediation, beneficial to plant survival in contaminated soil. Endophytic bacteria, strains FX1–FX3, and rhizosphere bacteria, strains FX0, FX4, and FX5, were isolated from the root tissue of a corn plant (Zea mays) and the corn rhizosphere near a chemical plant, respectively. The strains FX1–FX5 were able to grow on phenol and reduce phenol concentration, but the strain FX0 was unable to. The strains FX1, FX3, and FX4 were classified asPseudomonas fluorescensand FX0, FX2, and FX5 asBurkholderia cepacia. The plasmids isolated from the strains FX1–FX5 were found to possess similar traits and to be loaded with a gene encoding the catechol 2, 3-dioxygenase (C23O), a key enzyme in the phenol degradation pathway. Alignment and phylogenetic analysis inferred that in situ horizontal transfer of the C23O gene might have occurred. The horizontal transfer of the C23O gene between endophytic and rhizosphere bacteria was proved by using conjugal matings experiment, in which the transconjugants were found to acquire the plasmid with the C23O gene, able to grow on phenol and degrade phenol.