State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, 3 Taicheng Road, Yangling, Shaanxi, 712100, People's Republic of China.
Interdisciplinary Research Center for Soil Microbial Ecology and Land Sustainable Productivity in Dry Areas, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
Microbiome. 2023 May 22;11(1):109. doi: 10.1186/s40168-023-01511-3.
Allelopathy is closely associated with rhizosphere biological processes, and rhizosphere microbial communities are essential for plant development. However, our understanding of rhizobacterial communities under influence of allelochemicals in licorice remains limited. In the present study, the responses and effects of rhizobacterial communities on licorice allelopathy were investigated using a combination of multi-omics sequencing and pot experiments, under allelochemical addition and rhizobacterial inoculation treatments.
Here, we demonstrated that exogenous glycyrrhizin inhibits licorice development, and reshapes and enriches specific rhizobacteria and corresponding functions related to glycyrrhizin degradation. Moreover, the Novosphingobium genus accounted for a relatively high proportion of the enriched taxa and appeared in metagenomic assembly genomes. We further characterized the different capacities of single and synthetic inoculants to degrade glycyrrhizin and elucidated their distinct potency for alleviating licorice allelopathy. Notably, the single replenished N (Novosphingobium resinovorum) inoculant had the greatest allelopathy alleviation effects in licorice seedlings.
Altogether, the findings highlight that exogenous glycyrrhizin simulates the allelopathic autotoxicity effects of licorice, and indigenous single rhizobacteria had greater effects than synthetic inoculants in protecting licorice growth from allelopathy. The results of the present study enhance our understanding of rhizobacterial community dynamics during licorice allelopathy, with potential implications for resolving continuous cropping obstacle in medicinal plant agriculture using rhizobacterial biofertilizers. Video Abstract.
化感作用与根际生物过程密切相关，根际微生物群落对植物发育至关重要。然而，我们对受甘草化感物质影响的根际细菌群落的了解仍然有限。在本研究中，我们采用多组学测序和盆栽实验相结合的方法，在添加化感物质和接种根际细菌的处理下，研究了根际细菌群落对甘草化感作用的响应和影响。
我们证明了外源性甘草酸抑制甘草生长，并重塑和富集了与甘草酸降解相关的特定根际细菌和功能。此外，新鞘氨醇单胞菌属在富集分类群中占有相对较高的比例，并出现在宏基因组组装基因组中。我们进一步描述了单一和合成接种剂降解甘草酸的不同能力，并阐明了它们缓解甘草化感作用的不同效力。值得注意的是，单一补充的 N（新鞘氨醇单胞菌树脂诺罗）接种剂在甘草幼苗中具有最大的化感缓解效果。
总之，这些发现强调了外源性甘草酸模拟了甘草的化感自毒作用，而土著单一根际细菌在保护甘草生长免受化感作用方面比合成接种剂具有更大的效果。本研究结果增强了我们对甘草化感作用过程中根际细菌群落动态的理解，对于利用根际细菌生物肥料解决药用植物农业中的连作障碍具有潜在意义。
