根瘤菌共生固氮能力的进化模式

Evolution of rhizobial nodulation and nitrogen fixation

摘要:

根瘤菌-豆科植物共生固氮体系对农业的可持续性发展至关重要，也是研究原核与真核生物互利共生的模式体系之一。长期以来，根瘤菌共生固氮相关研究主要集中在结瘤因子与固氮酶合成及调控等少数关键基因，但仅获得这些关键基因却不能保证细菌获得结瘤固氮能力。随着比较和功能基因组学的快速发展和应用，越来越多的研究发现根瘤菌使用了很多系统发育分支特异的遗传机制与豆科植物建立有效的共生关系，进一步揭示了双方互利共生的复杂性。本综述总结了近年来比较基因组学、遗传学以及实验进化等方面的相关研究进展，在此基础上讨论根瘤菌共生固氮能力的进化模式。

Abstract:

Symbiosis between rhizobia and legumes is not only very important for the sustainable agriculture but also known as one of the model systems to study the mutualism between prokaryotes and eukaryotes. For a long time, studies on symbiotic nitrogen fixation of rhizobia have mainly focused on the role of key symbiosis genes involved in biosynthesis and regulation of Nod factors and nitrogenase. However, receiving these key genes does not guarantee rhizobia an effective symbiosis with legumes. Along with the rapid development and application of comparative and functional genomics, accumulated evidences indicate that rhizobia have recruited many lineage-specific dispensable genes to establish effective symbiosis with legumes, further revealing the complexity of mutualistic symbiosis. Here we review the cumulative evidence from recent genomics, genetics and experimental evolution studies to discuss the evolution of this complex symbiotic trait.