International Centre of Insect Physiology and Ecology, P.O. Box 30772-00100, Nairobi, Kenya.
Department of Zoology and Entomology, University of Pretoria, Private Bag x20 Hatfield, Pretoria, South Africa.
BMC Microbiol. 2024 Mar 18;24(1):92. doi: 10.1186/s12866-024-03238-z.
The soil biota consists of a complex assembly of microbial communities and other organisms that vary significantly across farming systems, impacting soil health and plant productivity. Despite its importance, there has been limited exploration of how different cropping systems influence soil and plant root microbiomes. In this study, we investigated soil physicochemical properties, along with soil and maize-root microbiomes, in an agroecological cereal-legume companion cropping system known as push-pull technology (PPT). This system has been used in agriculture for over two decades for insect-pest management, soil health improvement, and weed control in sub-Saharan Africa. We compared the results with those obtained from maize-monoculture (Mono) cropping system.
The PPT cropping system changed the composition and diversity of soil and maize-root microbial communities, and led to notable improvements in soil physicochemical characteristics compared to that of the Mono cropping system. Distinct bacterial and fungal genera played a crucial role in influencing the variation in microbial diversity within these cropping systems. The relative abundance of fungal genera Trichoderma, Mortierella, and Bionectria and bacterial genera Streptomyces, RB41, and Nitrospira were more enriched in PPT. These microbial communities are associated with essential ecosystem services such as plant protection, decomposition, carbon utilization, bioinsecticides production, nitrogen fixation, nematode suppression, phytohormone production, and bioremediation. Conversely, pathogenic associated bacterial genus including Bryobacter were more enriched in Mono-root. Additionally, the Mono system exhibited a high relative abundance of fungal genera such as Gibberella, Neocosmospora, and Aspergillus, which are linked to plant diseases and food contamination. Significant differences were observed in the relative abundance of the inferred metabiome functional protein pathways including syringate degradation, L-methionine biosynthesis I, and inosine 5'-phosphate degradation.
Push-pull cropping system positively influences soil and maize-root microbiomes and enhances soil physicochemical properties. This highlights its potential for agricultural and environmental sustainability. These findings contribute to our understanding of the diverse ecosystem services offered by this cropping system where it is practiced regarding the system's resilience and functional redundancy. Future research should focus on whether PPT affects the soil and maize-root microbial communities through the release of plant metabolites from the intercrop root exudates or through the alteration of the soil's nutritional status, which affects microbial enzymatic activities.
土壤生物群由微生物群落和其他生物体组成，这些生物体在不同的农业系统中差异显著，影响着土壤健康和植物生产力。尽管它很重要，但对于不同的种植系统如何影响土壤和植物根际微生物组的研究还很有限。在这项研究中，我们调查了农业生态系统中的谷物-豆科伴作种植系统（推-拉技术，PPT）中的土壤物理化学性质以及土壤和玉米根际微生物组。该系统在撒哈拉以南非洲地区已被用于农业 20 多年，用于管理虫害、改善土壤健康和控制杂草。我们将结果与玉米单作（Mono）种植系统的结果进行了比较。
PPT 种植系统改变了土壤和玉米根际微生物群落的组成和多样性，并导致土壤物理化学特性的显著改善，与 Mono 种植系统相比。在这些种植系统中，细菌和真菌属的独特种类在影响微生物多样性的变化方面起着至关重要的作用。真菌属 Trichoderma、Mortierella 和 Bionectria 以及细菌属 Streptomyces、RB41 和 Nitrospira 在 PPT 中的相对丰度更高。这些微生物群落与植物保护、分解、碳利用、生物杀虫剂生产、固氮、线虫抑制、植物激素生产和生物修复等重要的生态系统服务相关。相反，在 Mono 根际中，与病原菌相关的细菌属 Bryobacter 更为丰富。此外，Mono 系统中真菌属 Gibberella、Neocosmospora 和 Aspergillus 的相对丰度较高，这些真菌属与植物病害和食物污染有关。在推断的代谢物功能蛋白途径的相对丰度方面观察到显著差异，包括丁香酸降解、L-蛋氨酸生物合成 I 和肌苷 5'-磷酸降解。
推-拉种植系统对土壤和玉米根际微生物组产生积极影响，并增强土壤物理化学性质。这突出了其在农业和环境可持续性方面的潜力。这些发现有助于我们了解该种植系统在实践中提供的各种生态系统服务，以及该系统的弹性和功能冗余性。未来的研究应集中于 PPT 是否通过间作根渗出物中植物代谢物的释放或通过改变土壤的营养状况（影响微生物酶活性）来影响土壤和玉米根际微生物群落。
