Metagenomics-based exploration of key soil microorganisms contributing to continuously planted Casuarina equisetifolia growth inhibition and their interactions with soil nutrient transformation

• Published in: Frontiers in plant science 2023-12, Vol.14, p.1324184-1324184
• Main Authors: Wang, Yuhua, Lin, Shaoxiong, Li, Jianjuan, Jia, Xiaoli, Hu, Mingyue, Cai, Yuhong, Cheng, Pengyuan, Li, Mingzhe, Chen, Yiling, Lin, Wenxiong, Wang, Haibin, Wu, Zeyan
• Format: Article
• Language: English
• Subjects: C. equisetifolia; continuous planting; gene function; metagenome; nutrient transformation; Plant Science; soil enzymes
• ISSN: 1664-462X; 1664-462X
• DOI: 10.3389/fpls.2023.1324184

( ) is an economically important forest tree species, often cultivated in continuous monoculture as a coastal protection forest. Continuous planting has gradually affected growth and severely restricted the sustainable development of the industry. In this study, we analyzed the effects of continuous planting on growth and explored the rhizosphere soil microecological mechanism from a metagenomic perspective. The results showed that continuous planting resulted in dwarfing, shorter root length, and reduced seedling root system. Metagenomics analysis showed that 10 key characteristic microorganisms, mainly , , and , were responsible for continuously planted trees. Quantitative analysis showed that the number of microorganisms in these three genera decreased significantly with the increase of continuous planting. Gene function analysis showed that continuous planting led to the weakening of the environmental information processing-signal transduction ability of soil characteristic microorganisms, and the decrease of trees against stress. Reduced capacity for metabolism, genetic information processing-replication and repair resulted in reduced microbial propagation and reduced microbial quantity in the rhizosphere soil of trees. Secondly, amino acid metabolism, carbohydrate metabolism, glycan biosynthesis and metabolism, lipid metabolism, metabolism of cofactors and vitamins were all significantly reduced, resulting in a decrease in the ability of the soil to synthesize and metabolize carbon and nitrogen. These reduced capacities further led to reduced soil microbial quantity, microbial carbon and nitrogen, microbial respiration intensity, reduced soil enzyme nutrient cycling and resistance-related enzyme activities, a significant reduction in available nutrient content of rhizosphere soils, a reduction in the ion exchange capacity, and an impediment to growth. This study provides an important basis for the management of continuously planted plantations.