Siderophore cross-utilization amongst rhizospheric bacteria and the role of their differential affinities for Fe3+ on growth stimulation under iron-limited conditions
Siderophore cross-utilization amongst rhizospheric bacteria and the role of their differential affinities for Fe3+ on growth stimulation under iron-limited conditions
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DOI：
10.1007/s00284-005-0400-8
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发表时间：
2006-08-01
影响因子：
2.6
通讯作者：
Desai, Anjana
中科院分区：
文献类型：
--
作者：
Joshi, Falguni;Archana, G.;Desai, Anjana
从花生和绿豆根际分离的大多数细菌主要产生儿茶酚型铁载体，除了少数荧光假单胞菌产生儿茶酚酸盐外，还产生羟酸盐。根际分离株在交叉利用其他根际分离株（异种）产生的铁载体的能力上存在差异；有些人对异种铁载体的利用非常熟练，而另一些人则不善于交叉利用。分离物G9既利用了羟肟酸，也利用了儿茶酚酸铁载体，是一种高效的铁载体交叉利用物，而分离物G2和G6对儿茶酚酸利用较差，对羟肟酸铁载体不利用。两个分离株G9和G6在外部供应的异源铁载体存在的情况下生长，它们相互交叉利用。铁调节外膜蛋白（IROMP）谱在交叉利用程度最高和最少的菌株中存在差异，但在这两种情况下，均未诱导新的外膜蛋白（OMP）响应外源铁载体的供应。在分离物G9的情况下，在它们未能交叉利用的异源铁载体存在下的生物体生长导致生长抑制。这似乎是由于与外源提供的G6铁载体相比，G9的铁载体的亲和力较低。设计了一种简单的方法，在铁载体制备的CAS溶液脱色的基础上，测定了铁载体的相对亲和力。还讨论了铁载体对铁的不同亲和力对生长的影响以及生物之间通过交叉利用的相互作用。
The majority of bacteria isolated from rhizospheres of Arachis hypogea (Groundnut) and Vigna radiata (Mung bean) predominantly produced catechol-type siderophores except for a few fluorescent pseudomonads that produced hydroxamates in addition to catecholates. The rhizospheric isolates differed in their ability to cross-utilize siderophores produced by other rhizospheric isolates (heterologous); some were highly proficient at utilizing heterologous siderophores, while others were poor cross-utilizers. Isolate G9, which utilized hydroxamate as well as catecholate siderophores, was found to be an efficient siderophore cross-utilizer, while isolates G2 and G6 were poor-utilizers of catecholate and non-utilizers of hydroxamate siderophores. Growth stimulation of two isolates G9 and G6 was seen when grown in the presence of externally supplied heterologous siderophores, which they cross-utilized. The iron-regulated outer membrane protein (IROMP) profiles differed for the most cross-utilizer and the least cross-utilizer strains, but in both the cases no new outer membrane proteins (OMP) were induced in response to the exogenous siderophores supplied. The growth of the organisms in the presence of heterologous siderophores that they failed to cross-utilize led to growth inhibition in the case of isolate G9. This appears to be due to a lower affinity of the siderophore of G9 as compared to the exogenously supplied G6 siderophore. A simple method was devised to measure relative affinities of respective siderophores for iron based on CAS solution decolorization by the siderophore preparations. The effect on the growth of the differential affinities of the siderophores for iron and the interactions of the organisms through cross-utilization is also discussed.