Bacterial community assembly in the rhizosphere and endosphere of different perennial alfalfa varieties with low fall dormancy rates

doi:10.11686/cyxb2025190

Abstract

Abstract:

Plant growth and stress resilience rely on beneficial interactions between roots and symbiotic microorganisms. Low fall dormancy alfalfa （Medicago sativa） varieties exhibit strong adaptability to short-day and low-temperature conditions， but the characteristics of their root-associated microbial assemblies and cultivar-specific variations remain unclear. In this study， four low fall dormancy alfalfa cultivars-‘Lanmu No. 1’， ‘Gongnong No. 1’， ‘Golden empress’ （all M. sativa）， and ‘Gannong No. 1’ （Medicago lupulina） -were cultivated at a field experimental station in Gannan， Gansu Province. Using 16S rRNA gene amplicon sequencing， we analyzed rhizospheric and endophytic bacterial communities and their assembly mechanisms. The results show that bacterial alpha diversity was significantly higher in the rhizosphere than in endosphere， with distinct community structures observed among cultivars. Compared with the other cultivars， the cold-tolerant cultivar ‘Lanmu No. 1’ was uniquely enriched with Streptacidiphilus in the rhizosphere， showed increased endophytic bacterial diversity， and greater complexity and connectivity of microbial co-occurrence networks. Analysis of community assembly processes revealed that both rhizospheric and root endophytic communities were primarily governed by heterogeneous selection （42%-55%） and homogeneous selection （56%-83%）. Notably， deterministic selection had a stronger influence on root-associated communities in ‘Lanmu No. 1’， ‘Gongnong No. 1’， and ‘Gannong No. 1’ than in ‘Golden empress’. This study elucidates the assembly patterns and cultivar-driven divergence of root-associated microbiomes in low fall dormancy alfalfa. These results provide a theoretical foundation for microbiome manipulation to improve forage crop adaptability in cold， high-altitude regions.

Key words: perennial alfalfa, rhizosphere, endosphere, variety differences, co-occurrence network, community assembly

Zhao-ming WANG, Li-na ZHENG, Yue-hua ZHANG, Wei ZHAO, Xiang CHEN, Zhen-yu JIA. Bacterial community assembly in the rhizosphere and endosphere of different perennial alfalfa varieties with low fall dormancy rates[J]. Acta Prataculturae Sinica, 2026, 35(2): 195-207.

Figures/Tables 7

Fig.1 Field experiment setup （a， b） and sample collection and processing （c， d） in Gannan， Gansu Province

Fig.2 Differences in rhizosphere and endosphere microbial richness （a， b， c） and phylum level species composition （d） among different alfalfa varieties

Fig. 3 Beta diversity of rhizosphere and endophytic microorganisms in different alfalfa varieties

Fig.4 Number of microorganisms with significant differences in rhizosphere and endosphere abundance among alfalfa varieties and the taxonomy of microorganisms enriched in endosphere

Fig.5 Differential analysis of rhizosphere microorganisms between Lanmu No.1 （Lan1） and other varieties

Fig.6 The topological structures of the interaction network of rhizosphere and endophytic bacteria in different varieties

Fig.7 Community assembly processes of rhizosphere and endosphere bacteria in different alfalfa varieties

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