Islam Tofazzal, Hoque M Nazmul, Gupta Dipali Rani, Mahmud Nur Uddin, Sakif Tahsin Islam, Sharpe Andrew G
Institute of Biotechnology and Genetic Engineering (IBGE), Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur, Bangladesh.
Department of Gynecology, Obstetrics and Reproductive Health, BSMRAU, Gazipur, Bangladesh.
Front Microbiol. 2023 Jul 14;14:1212505. doi: 10.3389/fmicb.2023.1212505. eCollection 2023.
Plant probiotic bacteria enhance growth and yield of crop plants when applied at the appropriate time and dose. Two rice probiotic bacteria, strain BRRh-4 and sp. strain BTL-M2 promote growth and yield of plants. However, no information is available on application of these two bacteria on growth, yield, and diversity and population of bacteriome in roots and rhizosphere soils of the treated rice plants. This study aimed to assess the effect of BRRh-4 and BTL-M2 application on growth, yield and bacteriome in roots and rhizosphere soil of rice under varying doses of N, P and K fertilizers. Application of BRRh-4 and BTL-M2 strains significantly ( < 0.05) increased seed germination, growth and yield of rice compared to an untreated control. Interestingly, the grain yield of rice by these bacteria with 50% less of the recommended doses of N, P, and K fertilizers were statistically similar to or better than the rice plants treated with 100% doses of these fertilizers. Targeted amplicon (16S rRNA) sequence-based analysis revealed significant differences (PERMANOVA, = 0.00035) in alpha-diversity between the root (R) and rhizosphere soil (S) samples, showing higher diversity in the microbial ecosystem of root samples. Additionally, the bacteriome diversity in the root of rice plants that received both probiotic bacteria and chemical fertilizers were significantly higher (PERMANOVA, = 0.0312) compared to the rice plants treated with fertilizers only. Out of 185 bacterial genera detected, , an anaerobic and Gram-negative bacterium, was found to be the predominant genus in both rhizosphere soil and root metagenomes. However, the relative abundance of remained two-fold higher in the rhizosphere soil metagenome (52.02%) than in the root metagenome (25.04%). The other predominant bacterial genera detected in the rice root metagenome were (11.07%), (4.06%), (3.91%), (2.97%), (2.61%), and (2.30%). On the other hand, rhizosphere soil metagenome had (12.38%), (9.50%), (5.94%), (3.40%), and (3.02%). Interestingly, we found the presence and/or abundance of specific genera of bacteria in rice associated with the application of a specific probiotic bacterium. Taken together, our results indicate that improvement of growth and yield of rice by strain BRRh-4 and sp. strain BTL-M2 is likely linked with modulation of diversity, structures, and signature of bacteriome in roots and rhizosphere soils. This study for the first time demonstrated that application of plant growth promoting bacteria significantly improve growth, yield and increase the diversity of bacterial community in rice.
植物益生菌在适当的时间和剂量施用时可促进作物生长并提高产量。两种水稻益生菌，BRRh - 4菌株和BTL - M2菌株可促进植物生长并提高产量。然而，关于这两种细菌对处理过的水稻植株根系和根际土壤中细菌群落的生长、产量、多样性和种群的影响尚无相关信息。本研究旨在评估在不同氮、磷、钾肥料剂量下，施用BRRh - 4和BTL - M2对水稻根系和根际土壤中生长、产量和细菌群落的影响。与未处理的对照相比，施用BRRh - 4和BTL - M2菌株显著（<0.05）提高了水稻的种子萌发、生长和产量。有趣的是，这些细菌在氮、磷、钾肥料推荐剂量减少50%的情况下，其水稻籽粒产量在统计学上与施用100%这些肥料的水稻植株相似或更好。基于靶向扩增子（16S rRNA）序列的分析表明，根（R）和根际土壤（S）样品之间的α多样性存在显著差异（PERMANOVA，=0.00035），表明根样品的微生物生态系统具有更高的多样性。此外，与仅施用化肥的水稻植株相比，同时接受益生菌和化肥处理的水稻植株根系中的细菌群落多样性显著更高（PERMANOVA，=0.0312）。在检测到的185个细菌属中，一种厌氧革兰氏阴性菌，被发现是根际土壤和根系宏基因组中的优势属。然而，在根际土壤宏基因组中（52.02%）的相对丰度比根系宏基因组中（25.05%）高两倍。在水稻根系宏基因组中检测到的其他主要细菌属有（11.07%）、（4.06%）、（3.91%）、（2.97%）、（2.61%）和（2.30%）。另一方面，根际土壤宏基因组中有（12.38%）、（9.50%）、（5.94%）、（3.40%）和（3.02%）。有趣的是，我们发现水稻中特定细菌属的存在和/或丰度与特定益生菌的施用有关。综上所述，我们的结果表明，BRRh - 4菌株和BTL - M2菌株对水稻生长和产量的改善可能与根系和根际土壤中细菌群落的多样性、结构和特征的调节有关。本研究首次证明，施用植物生长促进细菌可显著改善水稻的生长、产量并增加细菌群落的多样性。
