Rodrigues Carla S, Laranjo Marta, Oliveira Solange
Departamento de Biologia, Universidade de Evora, Portugal.
Curr Microbiol. 2006 Jul;53(1):1-7. doi: 10.1007/s00284-005-4515-8. Epub 2006 May 22.
The development of rhizobial inoculants requires the selection of isolates that are symbiotically efficient as well as adapted to the local environmental conditions. Our aim was to find indigenous chickpea rhizobia tolerant to adverse environmental conditions, such as temperature and pH. Thirteen isolates of chickpea mesorhizobia from southern Portugal were examined. Tolerance to stress temperatures and pH was evaluated by quantification of bacterial growth at 20-37 degrees C and pH 5-9, respectively. Tolerance to heat shocks was studied by submitting isolates to 46 degrees C and 60 degrees C. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis protein analysis revealed qualitative and quantitative differences when isolates were submitted to temperature stress. A 60-kDa protein was overproduced by all isolates under heat stress. Almost all isolates revealed to be more tolerant to 20 degrees C than to 37 degrees C. A positive correlation was found between the maximum growth pH and the isolate origin soil pH. Generally, isolates more tolerant to temperature stress showed a lower symbiotic efficiency.
根瘤菌接种剂的开发需要选择共生效率高且适应当地环境条件的分离株。我们的目标是找到耐受不利环境条件（如温度和pH值）的本土鹰嘴豆根瘤菌。对来自葡萄牙南部的13株鹰嘴豆中慢生根瘤菌分离株进行了检测。分别通过在20 - 37℃和pH 5 - 9条件下对细菌生长进行定量，评估其对胁迫温度和pH值的耐受性。通过将分离株置于46℃和60℃来研究其对热休克的耐受性。十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳蛋白质分析显示，当分离株受到温度胁迫时，存在定性和定量差异。在热胁迫下，所有分离株均过量产生一种60 kDa的蛋白质。几乎所有分离株对20℃的耐受性都高于37℃。发现最大生长pH值与分离株来源土壤的pH值之间存在正相关。一般来说，对温度胁迫耐受性更强的分离株共生效率较低。
