Maize and peanut intercropping improves the nitrogen accumulation and yield per plant of maize by promoting the secretion of flavonoids and abundance of Bradyrhizobium in rhizosphere

Abstract

Belowground interactions mediated by root exudates are critical for the productivity and efficiency of intercropping systems. Herein, we investigated the process of microbial community assembly in maize, peanuts, and shared rhizosphere soil as well as their regulatory mechanisms on root exudates under different planting patterns by combining metabolomic and metagenomic analyses. The results showed that the yield of intercropped maize increased significantly by 21.05% (2020) and 52.81% (2021), while the yield of intercropped peanut significantly decreased by 39.51% (2020) and 32.58% (2021). The nitrogen accumulation was significantly higher in the roots of the intercropped maize than in those of sole maize at 120 days after sowing, it increased by 129.16% (2020) and 151.93% (2021), respectively. The stems and leaves of intercropped peanut significantly decreased by 5.13 and 22.23% (2020) and 14.45 and 24.54% (2021), respectively. The root interaction had a significant effect on the content of ammonium nitrogen (NH4+-N) as well as the activities of urease (UE), nitrate reductase (NR), protease (Pro), and dehydrogenase (DHO) in the rhizosphere soil. A combined network analysis showed that the content of NH4+-N as well as the enzyme activities of UE, NR and Pro increased in the rhizosphere soil, resulting in cyanidin 3-sambubioside 5-glucoside and cyanidin 3-O-(6-Op-coumaroyl) glucoside-5-O-glucoside; shisonin were significantly up-regulated in the shared soil of intercropped maize and peanut, reshaped the bacterial community composition, and increased the relative abundance of Bradyrhizobium. These results indicate that interspecific root interactions improved the soil microenvironment, regulated the absorption and utilization of nitrogen nutrients, and provided a theoretical basis for high yield and sustainable development in the intercropping of maize and peanut.

Microbiome convergence enables siderophore-secreting-rhizobacteria to improve iron nutrition and yield of peanut intercropped with maize

“…Furthermore, we found Azotobacter , a typical plant beneficial non-symbiotic nitrogen-fixing bacterial genus, to be cross-enriched from peanut to maize, possibly also contributing to improved nitrogen nutrition in maize. Our results are in line with previous findings on microbiota-dependent improvement of nitrogen nutrition 31 , 32 , 34 – 36 . Overall, legume/gramineae combinations are promising candidates for intercropping and are therefore the subject of intensive research in soil science and plant nutrition.…”

“…Maize and peanut could engage in a ‘giving-receiving feedback’ interaction through the convergence of their microbiomes in intercropping. Peanut plants are legumes and host nitrogen-fixing bacteria in their root nodules 31 , such that peanut could improve nitrogen acquisition of maize 27 , 32 . We indeed found evidence for this hypothesis.…”

AMF colonization affects allelopathic effects of Zea mays L. root exudates and community structure of rhizosphere bacteria

“…The potential role of plant root exudates has been verified by many researchers ( Baetz and Martinoia, 2014 ), which includes the effect of root exudates on plants themselves ( Li et al., 2019 ), on other plants ( Dong et al., 2022 ), on microorganisms and even on soil ecosystems ( Tian et al., 2021 ). In this study, it was found that maize root exudates inhibited the seed germination of radish, cucumber, lettuce, pepper, and ryegrass, and AMF colonization alleviated the inhibition of maize root exudates on the seed germination of the above recipient plants.…”

The effect of white grub (Maladera Verticalis) larvae feeding on rhizosphere microbial characterization of aerobic rice (Oryza sativa L.) in Puer City, Yunnan Province, China

“…We observed that M. verticalis larvae-feeding significantly enriched Bradyrhizobium (bacterial genus) and Talaromyces (fungal genus), and the relative abundance of Bradyrhizobium and Talaromyces gradually increased with the elevation of the larvae density. Notably, Bradyrhizobium is one of the most cosmopolitan and diverse bacterial group modulating a variety of host legumes, which can promote growth, increase yield, and improve abiotic stresses resistance [ 47 , 48 ] in various plants, including rice [ 49 ] peanuts [ 50 ], and maize [ 51 ]. In addition, Talaromyces can promote plant growth and inhibit pathogenic fungi and insects [ 52 – 54 ], such as Talaromyces apiculatus reduced linear mycelial growth of Ganoderma boninense , elevated area and bole girth of oil-palm seedlings, and increased shoot and root biomass, and nutrient contents in seedlings [ 52 ].…”