Agricultural microbiology seeks to replace the use of agrochemicals with microbe-based products. Plant growth-promoting bacteria (PGPB) are often selected based on their functions , and then, their effect on plant development is tested. However, this approach neglects the study of their survival in soil, root-colonization, and the monitoring of beneficial functions in the rhizosphere. This could explain the recurrent lack of success in the transition from lab tests to field applications of natural isolates from novel habitats. In our recent studies, we found that native maize seeds from traditional agroecosystems carry endophytic bacterial communities that are dominated by members of the class Bacilli. As an approach to grasp their PGP potential, we generated a collection of Bacilli isolates from 10 native maize landraces and developed protocols to test maize root-colonization of these natural isolates in 1) a short-term hydroponics assay and 2) a long-term assay in non-sterile soil pots. Our results show that biofilm formation was only partially associated to short-term colonization ; furthermore, long-term root-colonization in soil pots was not correlated to the assays. This work highlights the necessity to incorporate root-colonization assays as part of the research strategies in the search for PGPB natural isolates from unexplored habitats, towards the generation of inoculants with increased success in the field.

中文翻译：

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从本地玉米地方品种中分离出的种子内生芽孢杆菌的生物膜形成和玉米根定植

农业微生物学试图用基于微生物的产品取代农用化学品的使用。植物促生长细菌（PGPB）通常根据其功能进行选择，然后测试它们对植物发育的影响。然而，这种方法忽视了对它们在土壤中的生存、根部定植以及根际有益功能的监测的研究。这可以解释从新栖息地的天然分离物从实验室测试到现场应用的过渡经常缺乏成功的原因。在我们最近的研究中，我们发现来自传统农业生态系统的本地玉米种子携带以芽孢杆菌纲成员为主的内生细菌群落。作为掌握其 PGP 潜力的一种方法，我们从 10 个本地玉米地方品种中收集了芽孢杆菌分离株，并制定了测试这些天然分离株在玉米根部定植的方案，方法为 1) 短期水培测定和 2) 长期水培测定在非无菌土盆中进行测定。我们的结果表明，生物膜的形成仅部分与短期定植相关；此外，土壤盆中的长期根部定殖与测定无关。这项工作强调了将根定植测定​​纳入研究策略的一部分，以从未开发的栖息地中寻找 PGPB 天然分离物，以在该领域取得更大成功的接种剂的产生。