Zhang Ruifu Research Group of Nanjing Agricultural University Adv. SCI: The simplest rhizosphere synthetic flora inhibits the assembly process and mechanism of action of Fusarium species

Innovation: The team took the inhibition of Fusarium corn as the starting point, established a process for constructing rhizosphere simplification and stable flora, and added the unique advantages of "structural stability" and "composition simplification" on the basis of the traditional microbiota synthesis concept.
At the same time, the synthetic flora in this study has a unique cooperation mode and mechanism
of "core strains attacking enemies and other members increasing efficiency".
This study provides a new understanding for the construction of crop rhizosphere simplification and stabilization of microflora and inhibition of pathogenic bacteria, which has great scientific research value and application prospects
.

Keywords: species-borne pathogenic bacteria, rhizosphere core strains, simplified synthetic flora, synergistic and efficient

The rhizosphere microbiome plays an important role in plant growth and health, and regulating the rhizosphere microbiome can promote plant growth and improve the ability
of plants to tolerate environmental stresses.
Therefore, finding stable functional connections from complex plant-microbial interactions, and designing rhizosphere synthetic flora with high stability and strong colonization power for crops, can provide efficient inoculating agents for agricultural production.

Taking Fusarium corn seed as the starting point, this study first compares the differences in the composition of healthy and diseased maize rhizosphere bacterial communities under the two strategies of limit dilution and root exudate culture, excavates the characteristic bacterial taxa that is significantly enriched in healthy maize rhizosphere, and uses its pure culture strains to construct rhizosphere synthetic flora, and then optimizes the synthetic flora to a minimal synthetic flora
according to the characteristics of stable rhizosphere colonization, efficient disease suppression, and metabolic and growth synergy 。 Furthermore, through strain plate confrontation, genomic analysis and key gene mutant verification, it was proved that the effect of synthetic flora in inhibiting Fusarium is mainly the antibacterial lipopeptide fencain synthesized by Bacillus core.
Other members of the synthetic flora can enhance the functional expression of the core strain, such as promoting the growth of the core strain, increasing the expression level of the synthetic gene of the core strain of fencain, improving the expression of genes related to plant growth promotion of the core strain, and improving the stability of the synthetic flora by metabolic mutual trophic (Figure 1).

The minimally constructed synthetic bacterial group "combat unit" has formed a unique interaction mode and mechanism of "core strain attacking the enemy and other members increasing efficiency", which has an efficient prevention and control effect on the species transmission of Fusarium of the main maize cultivars in various planting areas in China
.
This study elucidates for the first time the mechanism of synergy and efficiency among members of synthetic flora from the perspective of internal interaction of synthetic flora, and also provides a new understanding
for the construction of crop rhizosphere simplification and stability of microflora and inhibition of pathogenic bacteria.
The research group also further explored and developed the high-density mixed fermentation technology of synthetic flora, which has the effects of minimizing substrate consumption, efficient resource utilization, maximizing strain biomass and homogenizing strain composition, and the relevant patents have entered the substantive examination stage, and the research results have strong application potential
.

Figure 1.
Conceptual diagram
of synthetic flora synergistic interaction to efficiently inhibit Fusarium in maize species.
This synthetic group consists of core functional strains (Bacillus sp.
), and can promote the growth of core strains (Burkholderia sp.
), promote core strain antagonistic gene expression (Pseudoxanthomonas sp.
and Stenotrophomonas sp.
), and promote core strain growth-promoting gene expression (Acinetobacter sp.
, Pseudoxanthomonas).
strains of sp.
, Pseudomonas sp.
and Stenotrophomonas sp.
), as well as strains
that promote synthetic flora stabilization (Pseudoxanthomonas sp.
, Enterobacter sp.
and Lysobacter sp.
).

The work was published in Advanced under the title "Sustained Inhibition of Maize Seed-Borne Fusarium Using a Bacillus-Dominated Rhizospheric Stable Core Microbiota with Unique Cooperative Patterns.
" Science (DOI:10.
1002/advs.
202205215), the first author of the article is Associate Professor Xun Weibing of Nanjing Agricultural University, the corresponding author is Professor Zhang Ruifu of Nanjing Agricultural University, Zhongshan Young Researcher Ren Yi and graduate students Yan He, Ma Eyuan, Liu Zihao, Wang Lingling and many teachers in the research group participated in the research work
.
The research was also supported by the National Key Research and Development Program of China and the National Natural Science Foundation of China
.

WILEY

Paper Information:

Sustained Inhibition of Maize Seed-Borne Fusarium Using a Bacillus-Dominated Rhizospheric Stable Core Microbiota with Unique Cooperative Patterns

Weibing Xun*, Yi Ren, He Yan, Aiyuan Ma, Zihao Liu, Lingling Wang, Nan Zhang, Zhihui Xu, Youzhi Miao, Haichao Feng, Qirong Shen, Ruifu Zhang*

Advanced Science

DOI：10.
1002/advs.
202205215

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