College of Horticulture, China Agricultural University, Beijing, China.
Key Laboratory of Biology and Genetic Improvement of Horticultural (Nutrition and Physiology), The Ministry of Agriculture, China Agricultural University, Beijing, China.
J Appl Microbiol. 2019 Feb;126(2):595-607. doi: 10.1111/jam.14121. Epub 2018 Nov 22.
To select apple rootstocks that are tolerant to low nitrogen and reveal the relationship between the rhizosphere bacterial communities and the low nitrogen tolerance of the apple rootstock.
In total, 235 lines of hybrids of Malus robusta Rehd. × M.9 with low nitrogen stress were cultivated in pots in a greenhouse equipped with a drip irrigation system, and growth characteristics, photosynthesis traits and mineral elements were monitored. The bacterial community structure of the rhizosphere from different rootstocks was determined via Illumina MiSeq sequencing. This study selected three low nitrogen-tolerant (NT) lines that had higher nitrogen concentration, and higher photosynthesis rate than the three low nitrogen-sensitive (NS) lines. The bacterial community structure significantly differed (P ≤ 0·001) among the rootstocks. The bacterial phyla Proteobacteria and Actinobacteria were the dominant groups in the rhizosphere and presented higher abundance in the NT rhizosphere. The N concentration in the apple rootstocks exhibited highly positive Pearson correlations with the bacterial genera Sphingomonas, Pseudoxanthomonas, Bacillus and Acinetobacter, and negative correlations with the bacterial genera Pseudarthrobacter and Bradyrhizobium.
This study showed that investigated rootstocks achieved increased nitrogen concentration by enhancing their photosynthetic production capacity and shaping their rhizobacteria community structure.
The findings provide a basis for studying the mechanisms of resistance to low nitrogen stress in apple rootstocks. Based on these beneficial bacteria, microbial inoculants can be developed for use in sustainable agricultural and horticultural production.
选择耐低氮的苹果砧木，并揭示其根际细菌群落与苹果砧木耐低氮能力的关系。
在温室滴灌系统的盆栽中，共种植了 235 个山定子（Malus robusta Rehd.）× M.9 杂种对低氮胁迫的品系，并监测其生长特性、光合作用特性和矿质元素。通过 Illumina MiSeq 测序确定了不同砧木根际的细菌群落结构。本研究选择了 3 个耐低氮（NT）的品系，其氮浓度和光合作用速率均高于 3 个耐低氮敏感（NS）的品系。根际细菌群落结构存在显著差异（P≤0.001）。根际中的细菌门 Proteobacteria 和 Actinobacteria 是主要群体，在 NT 根际中的丰度较高。苹果砧木中的氮浓度与 Sphingomonas、Pseudoxanthomonas、Bacillus 和 Acinetobacter 等细菌属呈高度正皮尔逊相关，与 Pseudarthrobacter 和 Bradyrhizobium 等细菌属呈负相关。
本研究表明，研究的砧木通过提高其光合作用生产能力和塑造其根际细菌群落结构来增加氮浓度。
该研究结果为研究苹果砧木耐低氮胁迫的机制提供了依据。基于这些有益细菌，可以开发微生物接种剂用于可持续的农业和园艺生产。
