Unraveling PDMA's Influence on Rhizosphere Microbial Communities

The rhizosphere is shaped by various exudates released by plant roots, which act as intermediaries between the plant and the soil. These exudates modify the root’s immediate environment, facilitating nutrient uptake and influencing the surrounding microbial community.

In response to iron-deficient conditions, Poaceae crops have developed a specialized strategy involving the targeted release of phytosiderophores. One such phytosiderophore, 2'-Deoxymugineic acid (DMA), effectively solubilizes otherwise inaccessible iron.

Plants like maize and peanuts absorb these DMA-iron complexes, enabling them to thrive despite iron scarcity. However, the practical application of DMA is limited due to its instability and high production costs. To address these challenges, researchers have synthesized a DMA analog, proline-2'-deoxymugineic acid (PDMA).

PDMA retains DMA’s key benefit of enhancing soil nutrient availability while overcoming its limitations. This makes PDMA a valuable tool for studying the impact of phytosiderophores on rhizosphere microbial communities, offering insights that could improve nutrient uptake efficiency in agriculture.

Professor Yuanmei Zuo’s research found that PDMA significantly altered the microbial community structure within the rhizosphere. In particular, PDMA application led to a notable enrichment of Actinobacteria at the phylum level in the peanut rhizosphere. At the genus level, Actinobacteria comprised six out of eleven enriched genera.

Further correlation analyses revealed a strong positive association between the relative abundance of Actinobacteria (and several of its genera) in the peanut rhizosphere and the bioavailability of key nutrients in both plants and soil. Notably, Cellulosimicrobium and Marmoricola appear to play critical roles in the activation of iron and zinc within the rhizosphere.

Network analysis showed that PDMA application resulted in a highly interconnected microbial network with tightly linked nodes. Additionally, PDMA enhanced environmental information processing, cellular processes, and genetic information processing capabilities in rhizobacteria.

Secondary pathway analysis further indicated that PDMA improved the biodegradation and metabolism of exogenous substances, signal transduction, cellular processes, and membrane transport in rhizobacteria.

This study underscores PDMA’s ability to establish a robust and interconnected microbial network in the rhizosphere, facilitating communication among microorganisms. It highlights PDMA’s potential as a novel functional fertilizer that strengthens the dynamic relationship between plants and beneficial rhizobacteria. The research was published in the Journal of Frontiers of Agricultural Science and Engineering.