Physiological Changes in Rhizobia after Growth in Peat Extract May Be Related to Improved Desiccation Tolerance
Physiological Changes in Rhizobia after Growth in Peat Extract May Be Related to Improved Desiccation Tolerance
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DOI：
10.1128/aem.00082-13
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发表时间：
2013-07-01
影响因子：
4.4
通讯作者：
Deaker, Rosalind
中科院分区：
文献类型：
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作者：
Casteriano, Andrea;Wilkes, Meredith A.;Deaker, Rosalind
与液体培养细胞相比，泥炭培养根瘤菌的存活率提高归因于潮湿泥炭中固态发酵期间的细胞适应。我们已经观察到改善的干燥耐受性豆科根瘤菌bv。三叶草TA 1和慢生大豆根瘤菌CB 1809在泥炭水浸提液中的有氧生长。生存的TA 1生长在粗泥炭提取物是18倍以上的细胞生长在一个确定的液体培养基，但减少时，细胞生长在不同大小的胶体级分的泥炭提取物。当在粗泥炭提取物中生长时，CB 1809的存活率通常比对照组更好，但统计学上不显着（P > 0.05），并且强烈依赖于泥炭提取物浓度。在泥炭提取物中生长后，TA 1和CB 1809细胞内海藻糖的积累比在限定培养基对照中更高。在泥炭水提取物中生长的细胞表现出类似于在潮湿泥炭中生长后观察到的形态变化。电子显微镜显示增厚的质膜，电子致密的材料占据周质空间在TA 1和CB 1809。泥炭提取物中的生长也导致了两种菌株中多肽表达的变化，并且通过液相色谱-质谱法进行的肽分析表明应激反应蛋白的表达增加。我们的研究结果表明，提高根瘤菌的脱水耐受能力是多因素的，涉及海藻糖的积累，以及参与保护细胞被膜，修复DNA损伤，氧化应激反应，和维护蛋白质的稳定性和完整性的蛋白质的表达增加。
Improved survival of peat-cultured rhizobia compared to survival of liquid-cultured cells has been attributed to cellular adaptations during solid-state fermentation in moist peat. We have observed improved desiccation tolerance of Rhizobium leguminosarum bv. trifolii TA1 and Bradyrhizobium japonicum CB1809 after aerobic growth in water extracts of peat. Survival of TA1 grown in crude peat extract was 18-fold greater than that of cells grown in a defined liquid medium but was diminished when cells were grown in different-sized colloidal fractions of peat extract. Survival of CB1809 was generally better when grown in crude peat extract than in the control but was not statistically significant (P > 0.05) and was strongly dependent on peat extract concentration. Accumulation of intracellular trehalose by both TA1 and CB1809 was higher after growth in peat extract than in the defined medium control. Cells grown in water extracts of peat exhibit morphological changes similar to those observed after growth in moist peat. Electron microscopy revealed thickened plasma membranes, with an electron-dense material occupying the periplasmic space in both TA1 and CB1809. Growth in peat extract also resulted in changes to polypeptide expression in both strains, and peptide analysis by liquid chromatography-mass spectrometry indicated increased expression of stress response proteins. Our results suggest that increased capacity for desiccation tolerance in rhizobia is multifactorial, involving the accumulation of trehalose together with increased expression of proteins involved in protection of the cell envelope, repair of DNA damage, oxidative stress responses, and maintenance of stability and integrity of proteins.