Laboratoire de Biotechnologies Végétales Appliquées à l'Amélioration des Cultures, Faculté des Sciences de Gabès, Université de Gabes, Cité Erriadh Zrig, 6072, Gabès, Tunisia.
Arch Microbiol. 2011 Jun;193(6):385-97. doi: 10.1007/s00203-011-0683-z. Epub 2011 Feb 27.
Diversity of 50 bacterial isolates recovered from root nodules of Prosopis farcta grown in different arid soils in Tunisia, was investigated. Characterization of isolates was assessed using a polyphasic approach including phenotypic characteristics, 16S rRNA gene PCR--RFLP and sequencing, nodA gene sequencing and MLSA. It was found that most of isolates are tolerant to high temperature (40°C) and salinity (3%). Genetic characterization emphasizes that isolates were assigned to the genus Ensifer (80%), Mesorhizobium (4%) and non-nodulating endophytic bacteria (16%). Forty isolates belonging to the genus Ensifer were affiliated to Ensifer meliloti, Ensifer xinjiangense/Ensifer fredii and Ensifer numidicus species. Two isolates belonged to the genus Mesorhizobium. Eight isolates failing to renodulate their host plant were endophytic bacteria and belonged to Bacillus, Paenibacillus and Acinetobacter genera. Symbiotic properties of nodulating isolates showed a diversity in their capacity to infect their host plant and fix atmospheric nitrogen. Isolate PG29 identified as Ensifer meliloti was the most effective one. Ability of Prosopis farcta to establish symbiosis with rhizobial species confers an important advantage for this species to be used in reforestation programs. This study offered the first systematic information about the diversity of microsymbionts nodulating Prosopis farcta in the arid regions of Tunisia.
从突尼斯不同干旱土壤中生长的刺槐根瘤中分离出的 50 株细菌的多样性进行了研究。采用多相方法评估分离株的特征，包括表型特征、16S rRNA 基因 PCR-RFLP 和测序、nodA 基因测序和 MLSA。结果发现，大多数分离株能耐受高温（40°C）和盐度（3%）。遗传特征强调，分离株被分配到根瘤菌属（80%）、中慢生根瘤菌属（4%）和非结瘤内生细菌（16%）。40 株属于根瘤菌属的分离株与苜蓿根瘤菌、新疆根瘤菌/弗雷氏根瘤菌和努比亚根瘤菌种有关。2 株属于中慢生根瘤菌属。未能重新感染其宿主植物的 8 株内生细菌属于芽孢杆菌属、类芽孢杆菌属和不动杆菌属。结瘤分离株的共生特性显示出其感染宿主植物和固定大气氮的能力的多样性。鉴定为苜蓿根瘤菌的 PG29 是最有效的一株。刺槐与根瘤菌物种建立共生关系的能力为该物种在造林计划中的应用提供了重要优势。本研究首次提供了关于突尼斯干旱地区结瘤刺槐的微共生体多样性的系统信息。
