Nodulation competitiveness as a requisite for improved rhizobial inoculants of Trifolium pratense
Nodulation competitiveness as a requisite for improved rhizobial inoculants of Trifolium pratense
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DOI：
10.1007/s00374-014-0946-3
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发表时间：
2015-01-01
影响因子：
6.5
通讯作者：
Monza, Jorge
中科院分区：
文献类型：
--
作者：
Batista, Leticia;Irisarri, Pilar;Monza, Jorge
三叶草（Trifolium pratense L.）在乌拉圭用于草地改良，并且自20世纪70年代以来已经用三叶草根瘤菌的商业菌株U204接种。土壤中存在的天然驯化根瘤菌菌株是选择和开发新接种剂的基础。有了这个目标，我们评估了红三叶草根瘤菌在乌拉圭红三叶草牧场的多样性，历史上接种U204和非接种的。鉴定了38种不同的肠细菌重复基因间共有序列（ERIC）PCR基因组指纹，尽管令人惊讶的是，80个分离株中只有一个显示出与U204相似的ERIC谱。在受控条件下，用天然分离物之一菌株317接种的红三叶草植物比用商业U204接种的那些产生更多的生物量。ERIC-PCR结果也表明，在有接种史的田间，菌株317比U204具有更好的产孢竞争。此外，U204和317都标记了gusA报告基因，并在各种土壤类型中评估了它们的竞争力。再次，菌株317似乎比U204更有竞争力，特别是在有接种历史的土壤中。我们的研究结果加强了长期以来的想法，评估接种豆科植物在不同土壤中的实际需求，并建议土著分离物317是一种有效的和有竞争力的菌株，可用于开发一种新的红三叶草接种剂。
Red clover (Trifolium pratense L.) is used in the improvement of grasslands in Uruguay and has been inoculated with commercial strain U204 of Rhizobium leguminosarum bv trifolii since 1970s. Native-naturalized rhizobia strains present in soil are the basis for selecting and developing new inoculants. With this aim, we evaluated the diversity of red clover rhizobia in Uruguayan red clover pastures both historically inoculated with U204 and non-inoculated ones. Thirty-eight different enterobacterial repetitive intergenic consensus (ERIC) PCR genomic fingerprints were identified, albeit surprisingly only one of 80 isolates showed an ERIC profile similar to U204. Under controlled conditions, red clover plants inoculated with one of the native isolates, strain 317, produced more biomass than those inoculated with the commercial U204. ERIC-PCR was also used to show that strain 317 competed for nodulation better than U204 in a field with previous history of inoculation. Moreover, both U204 and 317 were tagged with a gusA reporter gene and their competitiveness for nodulation assessed in various soil types. Again, strain 317 appeared more competitive than U204, particularly in soils with previous history of inoculation. Our results reinforce the long-known idea of assessing the actual needs of inoculation of legumes in different soils and suggest that the indigenous isolate 317 is an effective and competitive strain that can be used for development of a new red clover inoculant.