Plant growth promoting rhizobacteria (PGPR) are a group of bacteria that promote plants growth in the rhizosphere. PGPRs are involved in various mechanisms that reinforce plant development. In this study, we screened for PGPRs that were effective in early growth of Arabidopsis thaliana when added to the media and one Bacillus subtilis strain L1 (Bs L1) was selected for further study. When Bs L1 was placed near the roots, seedlings showed notably stronger growth than that in the control, particularly in biomass and root hair. Quantitative reverse transcription polymerase chain reaction analysis revealed a high level of expression of the high affinity nitrate transporter gene, NRT2.1 in A. thaliana treated with Bs L1. After considering how Bs L1 could promote plant growth, we focused on nitrate, which is essential to plant growth. The nitrate content was lower in A. thaliana treated with Bs L1. However, examination of the activity of nitrate reductase revealed higher activity in plants treated with PGPR than in the control. Bs L1 had pronounced effects in representative crops (wheat and lettuce). These results suggest that Bs L1 promotes the assimilation and use of nitrate and plant growth.

中文翻译：

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枯草芽孢杆菌菌株L1促进拟南芥中硝酸盐还原酶的活性，并提高拟南芥，生菜和小麦的生长性能。

促进植物生长的根际细菌（PGPR）是一组促进植物在根际中生长的细菌。PGPR参与了各种增强植物发育的机制。在这项研究中，我们筛选了添加到培养基中的对拟南芥早期生长有效的PGPR，并选择了一种枯草芽孢杆菌L1菌株（Bs L1）进行进一步研究。当Bs L1放在根部附近时，幼苗显示出比对照组明显更强的生长，特别是在生物量和根毛中。定量逆转录聚合酶链反应分析显示高亲和力硝酸盐转运蛋白基因NRT2.1在经Bs L1处理的拟南芥中高水平表达。在考虑Bs L1如何促进植物生长之后，我们集中研究了硝酸盐，这对于植物生长至关重要。Bs L1处理的拟南芥中硝酸盐含量较低。然而，对硝酸还原酶活性的检查显示，用PGPR处理的植物的活性高于对照。Bs L1在代表性作物（小麦和生菜）中具有明显的作用。这些结果表明，Bs L1促进硝酸盐的同化和利用以及植物的生长。