Listening to plant's Esperanto via root exudates: reprogramming the functional expression of plant growth‐promoting rhizobacteria

Abstract

Summary Rhizomicrobiome plays important roles in plant growth and health, contributing to the sustainable development of agriculture. Plants recruit and assemble the rhizomicrobiome to satisfy their functional requirements, which is widely recognized as the ‘cry for help’ theory, but the intrinsic mechanisms are still limited. In this study, we revealed a novel mechanism by which plants reprogram the functional expression of inhabited rhizobacteria, in addition to the de novo recruitment of soil microbes, to satisfy different functional requirements as plants grow. This might be an efficient and low‐cost strategy and a substantial extension to the rhizomicrobiome recruitment theory. We found that the plant regulated the sequential expression of genes related to biocontrol and plant growth promotion in two well‐studied rhizobacteria Bacillus velezensis SQR9 and Pseudomonas protegens CHA0 through root exudate succession across the plant developmental stages. Sixteen key chemicals in root exudates were identified to significantly regulate the rhizobacterial functional gene expression by high‐throughput qPCR. This study not only deepens our understanding of the interaction between the plant–rhizosphere microbiome, but also provides a novel strategy to regulate and balance the different functional expression of the rhizomicrobiome to improve plant health and growth.

Dynamic microbial regulation of triiron tetrairon phosphate nanomaterials in the tomato rhizosphere

“…Plants transfer photosynthate into the rhizosphere as root exudates, resulting in a notable distinction in the composition of the rhizosphere microbiome compared to that in bulk soil. 67 PGPR colonization in the rhizosphere is linked to root exudates, which serve as crucial signals mediating interactions between roots and microorganisms, 68 that can meet varying demands during the plant development stage, ultimately promoting plant quality and yield.…”

Biochar Enhances the Resistance of Legumes and Soil Microbes to Extreme Short-Term Drought

“…Trichoderma, as plant growth-promoting bacteria, can induce plant resilience to drought [ 85 , 86 ]. In return, plants can modulate the responses of soil microbes and root-associated microbes to drought via those tight linkages during extreme droughts [ 41 , 87 ]. Beneficial associations between plants and underground microbes may enhance plant tolerance to drought.…”

“…Additionally, the soil microbial community can interact with plants and influence plant resistance to drought [ 39 , 40 ]. Legume plants convene nitrogen-fixing bacteria in their nodules in order to obtain more N [ 41 , 42 ]. Legume cortical cells have the ability to divide, which allows them to form rhizomes to convene nitrogen-fixing bacteria [ 43 ].…”

Insight into bacterial and archaeal community structure of Suaeda altissima and Suaeda dendroides rhizosphere in response to different salinity level

“…On the other hand, plants adapt to biotic stress by changing their root exudation chemistry to assemble health-promoting microbiomes ( 32 ). This was be called “cry-for-help” hypothesis, and plants also can reprogram the functional expression of inhabited rhizobacteria to improve their adaptation and resistance to the stress ( 33 , 34 ). However, the composition of root exudates can vary among plant species, leading to the rhizosphere microbial community that varies due to different microbial preferences for root exudates ( 35 ).…”