Wei Gehong, Chen Weimin, Zhu Wenfei, Chen Chun, Young J Peter W, Bontemps Cyril
Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Life Science, Northwest A & F University, Yangling, Shaanxi, China.
FEMS Microbiol Ecol. 2009 Jun;68(3):320-8. doi: 10.1111/j.1574-6941.2009.00673.x. Epub 2009 Apr 6.
The aim of this work is to describe the diversity of potentially symbiotic bacteria associated with the invasive introduced legume Robinia pseudoacacia in China. Thirty-three isolates from 33 separate trees and nodules were characterized using restriction length fragment polymorphism and sequencing of 16S rRNA, nodA, nodC and nifH genes. Their 16S rRNA gene patterns and sequences placed them in three clades: 85% of isolates were related to the Mesorhizobium mediterraneum/temperatum group, whereas the remaining were similar either to Mesorhizobium amorphae or to Sinorhizobium meliloti. However, despite their diverse taxonomic positions, the nodA, nodC and nifH genes' phylogenies indicated that these R. pseudoacacia symbionts share similar symbiosis genes, implying gene transfers and a degree of host specificity. Comparison of R. pseudoacacia symbiotic diversity in native and other invaded areas suggests that most Chinese symbionts may not have arrived with the seed but were local bacteria that acquired specific symbiotic genes from native American rhizobia.
这项工作的目的是描述与中国外来入侵豆科植物刺槐相关的潜在共生细菌的多样性。从33棵独立的树木和根瘤中分离出33株菌株，采用限制性片段长度多态性以及16S rRNA、nodA、nodC和nifH基因测序进行表征。它们的16S rRNA基因模式和序列将它们分为三个进化枝：85%的分离株与地中海中生根瘤菌/温带中生根瘤菌群有关，而其余的则与非定型中生根瘤菌或苜蓿中华根瘤菌相似。然而，尽管它们的分类地位不同，但nodA、nodC和nifH基因的系统发育表明，这些刺槐共生体共享相似的共生基因，这意味着基因转移和一定程度的宿主特异性。对刺槐在原生地和其他入侵地区共生多样性的比较表明，大多数中国共生体可能不是随种子而来，而是当地细菌从美洲本土根瘤菌获得了特定的共生基因。
