Two bacterial strains isolated from a Zn-polluted soil enhance plant growth and mycorrhizal efficiency under Zn-toxicity.
Two bacterial strains isolated from a Zn-polluted soil enhance plant growth and mycorrhizal efficiency under Zn-toxicity.
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DOI：
10.1016/j.chemosphere.2005.06.053
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发表时间：
2006-03
期刊：
影响因子：
8.8
通讯作者：
A. Vivas;B. Biró;J. M. Ruiz-Lozano;J. Barea;R. Azcón
中科院分区：
文献类型：
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作者：
A. Vivas;B. Biró;J. M. Ruiz-Lozano;J. Barea;R. Azcón
本文研究了植物、根际微生物和锌污染之间的相互作用。我们测试了从锌污染土壤中分离的两种细菌菌株对植物生长的影响，并对本地丛枝菌根真菌（AMF）在锌毒害下的共生效率。这两个菌株表现出耐锌培养时，在培养基中增加锌水平。然而，菌株B-I在培养基中两个最高锌水平（75和100 mgl − 1 Zn）下表现出比菌株B-II更高的锌耐受性。分子鉴定将菌株B-I定位于短芽孢杆菌属。结果表明，B-I菌株对植物生长、氮磷积累、根瘤数和菌根侵染均有促进作用，表明其具有植物生长促进（PGP）活性。该菌株B-I已被证明产生IAA（3.95μ g/ml）并从生长培养基中积累5.6%的Zn。在三个锌水平下，AMF和细菌B-I双重接种的植株生长和营养都得到了增强。这种效应可能与共生结构（根瘤和AMF定植）的刺激和植物组织中锌浓度的降低有关。每根重单位获得的锌的量减少这些细菌菌株或AMF，特别是由混合细菌AMF接种。这些机制解释了所选微生物对锌毒性的缓解，并表明金属适应细菌和AMF在土壤锌污染下促进植物生长中起着关键作用。
In this study we investigated the interactions among plant, rhizosphere microorganisms and Zn pollution. We tested the influence of two bacterial strains isolated from a Zn-polluted soil on plant growth and on the symbiotic efficiency of native arbuscular mycorrhizal fungi (AMF) under Zn toxicity. The two bacterial strains exhibited Zn tolerance when cultivated under increasing Zn levels in the medium. However, strain B-I showed a higher Zn tolerance than strain B-II at the two highest Zn levels in the medium (75 and 100mgl−1Zn). Molecular identification placed the strain B-I within the genus Brevibacillus. Our results showed that bacterial strain B-I consistently enhanced plant growth, N and P accumulation, as well as nodule number and mycorrhizal infection which demonstrated its plant-growth promoting (PGP) activity. This strain B-I has been shown to produce IAA (3.95μgml) and to accumulate 5.6% of Zn from the growing medium. The enhanced growth and nutrition of plants dually inoculated with the AMF and bacterium B-I was observed at three Zn levels assayed. This effect can be related to the stimulation of symbiotic structures (nodules and AMF colonization) and a decreased Zn concentration in plant tissues. The amount of Zn acquired per root weight unit was reduced by each one of these bacterial strains or AMF and particularly by the mixed bacterium-AMF inocula. These mechanisms explain the alleviation of Zn toxicity by selected microorganisms and indicate that metal-adapted bacteria and AMF play a key role enhancing plant growth under soil Zn contamination.