Effect of Two Different Sugarcane Cultivars on Rhizosphere Bacterial Communities of Sugarcane and Soybean Upon Intercropping

Abstract

Intercropping of soybean and sugarcane is an important strategy to promote sustainable development of the sugarcane industry. In fact, our understanding of the interaction between the rhizosphere and bacterial communities in the intercropping system is still evolving; particularly, the influence of different sugarcane varieties on rhizosphere bacterial communities in the intercropping process with soybean, still needs further research. Here, we evaluated the response of sugarcane varieties ZZ1 and ZZ9 to the root bacterial community during intercropping with soybean. We found that when ZZ9 was intercropped with soybean, the bacterial diversity increased significantly as compared to that when ZZ1 was used. ZZ9 played a major role in changing the bacterial environment of the root system by affecting the diversity of rhizosphere bacteria, forming a rhizosphere environment more conducive to the growth of sugarcane. In addition, our study found that ZZ1 and ZZ9 had differed significantly in their utilization of nutrients. For example, nutrients were affected by different functional genes in processes such as denitrification, P-uptake and transport, inorganic P-solubilization, and organic P-mineralization. These results are significant in terms of providing guidance to the sugarcane industry, particularly for the intercropping of sugarcane and soybean in Guangxi, China.

Rhizosphere Bacterial Networks, but Not Diversity, Are Impacted by Pea-Wheat Intercropping

“…In intercropping, biodiversity and structure of rhizosphere bacterial community of plant species/cultivars did not differ significantly from sole cropping in any of the two experiments ( Figure 1 ). This is consistent with previous reports made on wheat-fababean IC ( Tang et al, 2016 ) and on sugarcane varieties IC ( Liu et al, 2021 ). Differences between intercropping and sole cropping were only detected in pea, when pooling data from the two experiments.…”

“…Concerning IC co-occurrence network, Tang et al (2021) showed, through a shotgun metagenome analysis, that sugarcane and peanut IC increased the abundance of bacterial genes involved in organic matter turnover comparing to SC, without correlating these differences to changes in microbiota diversity. Liu et al (2021) showed differences between the co-occurrence networks between two sugarcane varieties in IC. None of these studies analyzed the differences in co-occurring network between bacterial taxa in IC and SC.These complex interactions may account for the increased yield of the IC but also of the following crop, indicating a positive legacy effect of multispecies cropping systems (Wang et al, 2020).…”

“…It has been hypothesized that this choice is also crucial to value beneficial plant-plant-microbe interactions. This is supported by the different responses of the root bacterial community of two sugarcane varieties when intercropped with soybean (Liu et al, 2021). Thus, identifying the appropriate plant partners in IC represent a major issue, this require to test different combinations of plant genotypes/cultivars.…”

“…Thus, attempts have been to assess the impact of IC on rhizosphere microbiota. Total microbial communities ( Taschen et al, 2017 ; Li et al, 2018 ; Gao et al, 2019 ; Liu et al, 2021 ; Tang et al, 2021 ) and specific functional guilds (e.g., ammonia oxidizing bacteria, Song et al, 2007 ; diazotrophic Proteobacteria, Solanki et al, 2020 ) from the total root systems of plant genotypes associated in IC have been analyzed. These reports evidenced that rhizosphere microbiota from IC and sole-cropping (SC) differ significantly, these differences being more strongly expressed for bacteria than for fungi ( Gong et al, 2019 ).…”

“…Biotic interactions do not only occur between plant-plant and plants-microbes, but also among microorganisms. An increasing attention is given to interaction networks between rhizosphere organisms ( van der Heijden and Hartmann, 2016 ) and the impact of IC on these networks has recently been stressed ( Liu et al, 2021 ; Tang et al, 2021 ). Thus, co-occurrence networks have been proposed as an additional parameter to characterize microbial communities ( Barberán et al, 2012 ; Berry and Widder, 2014 ; Morriën et al, 2017 ; de Vries et al, 2018 ; Li and Wu, 2018 ; Jacquiod et al, 2020 ).…”