Institute for Plant Molecular Biology, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China.
Yi Chuan. 2021 May 20;43(5):487-500. doi: 10.16288/j.yczz.20-409.
Low pH with aluminum (Al) toxicity are the main limiting factors affecting crop production in acidic soil. Selection of legume crops with acid tolerance and nitrogen-fixation ability should be one of the effective measures to improve soil quality and promote agricultural production. The role of the rhizosphere microorganisms in this process has raised concerns among the research community. In this study, BX10 (Al-tolerant soybean) and BD2 (Al-sensitive soybean) were selected as plant materials. Acidic soil was used as growth medium. The soil layers from the outside to the inside of the root are bulk soil (BS), rhizosphere soil at two sides (SRH), rhizosphere soil after brushing (BRH) and rhizosphere soil after washing (WRH), respectively. High-throughput sequencing of 16S rDNA amplicons of the V4 region using the Illumina MiSeq platform was performed to compare the differences of structure, function and molecular genetic diversity of rhizosphere bacterial community of different genotypes of soybean. The results showed that there was no significant difference in alpha diversity and beta diversity in rhizosphere bacterial community among the treatments. PCA and PCoA analysis showed that BRH and WRH had similar species composition, while BS and SRH also had similar species composition, which indicated that plant mainly affected the rhizosphere bacterial community on sampling compartments BRH and WRH. The composition and abundance of rhizosphere bacterial community among the treatments were then compared at different taxonomic levels. The ternary diagram of phylum level showed that Cyanobacteria were enriched in WRH. Statistical analysis showed that the roots of Al-tolerant soybean BX10 had an enrichment effect on plant growth promoting rhizobacteria (PGPR), which included Cyanobacteria, Bacteroides, Proteobacteria and some genera and species related to the function of nitrogen fixation and aluminum tolerance. The rhizosphere bacterial community from different sampling compartments of the same genotype soybean also were selectively enriched in different PGPR. In addition, the functional prediction analysis showed that there was no significant difference in the classification and abundance of COG (clusters of orthologous groups of proteins) function among different treatments. Several COGs might be directly related to nitrogen fixation, including COG0347, COG1348, COG1433, COG2710, COG3870, COG4656, COG5420, COG5456 and COG5554. Al-sensitive soybean BD2 was more likely to be enriched in these COGs than BX10 in BRH and WRH, and the possible reason remains to be further investigated in the future.
低 pH 值和铝（Al）毒性是影响酸性土壤中作物生产的主要限制因素。选择具有耐酸和固氮能力的豆科作物应该是改善土壤质量和促进农业生产的有效措施之一。根际微生物在这一过程中的作用引起了研究界的关注。本研究以耐铝大豆 BX10 和铝敏感大豆 BD2 为材料，以酸性土壤为生长介质，分别在根外侧、根两侧、根刷洗后、根冲洗后 4 个土壤层取样，利用 Illumina MiSeq 平台对 V4 区 16S rDNA 扩增子进行高通量测序，比较不同基因型大豆根际细菌群落结构、功能和分子遗传多样性的差异。结果表明，不同处理间根际细菌群落的α多样性和β多样性无显著差异。PCA 和 PCoA 分析表明，BRH 和 WRH 的种组成相似，BS 和 SRH 也具有相似的种组成，表明植物主要影响 BRH 和 WRH 采样区的根际细菌群落。然后在不同分类水平上比较了不同处理间根际细菌群落的组成和丰度。门水平的三元图显示 WRH 中蓝细菌富集。统计分析表明，耐铝大豆 BX10 的根对植物促生根际细菌（PGPR）有富集作用，包括蓝细菌、拟杆菌、变形菌门和一些与固氮和耐铝功能相关的属和种。同一基因型大豆不同采样区的根际细菌群落也选择性地富集了不同的 PGPR。此外，功能预测分析表明，不同处理间 COG（直系同源基因簇）功能的分类和丰度无显著差异。一些 COG 可能与固氮直接相关，包括 COG0347、COG1348、COG1433、COG2710、COG3870、COG4656、COG5420、COG5456 和 COG5554。在 BRH 和 WRH 中，铝敏感大豆 BD2 比 BX10 更有可能富集这些 COG，其原因有待进一步研究。
