Isolation, characterisation and genome analysis of a novel ginsenosides hydrolysing bacterium Ginsengibacter hankyongi gen. nov., sp. nov. isolated from soil

Recycled Phosphorus Bioamendments from Wastewater Impact Rhizomicrobiome and Benefit Crop Growth: Sustainability Implications at Water-Food Nexus

Phosphorus recovery through enhanced biological phosphorus removal (EBPR) processes from agricultural wastes holds promise in mitigating the impending global P shortage. However, the complex nutrient forms and the microbial augments, expected to exert a profound impact on crop rhizomicrobiome and thus crop health, remained unexplored. In this study, we investigated the impacts of EBPR biosolids on crops growth and rhizomicrobiome in comparison to chemical fertilizer and Vermont manure compost. Our findings revealed that EBPR biosolid augmentation promoted the best maize shoot growth traits with the least nutrient deficiency, evidencing its agricultural benefits. Biosolid augmentation significantly impacted the rhizomicrobiome with decreased biodiversity but higher activities with enriched taxa capable of utilizing various carbon sources. The novel single-cell Raman spectroscopy phenotyping technique uncovered the surprisingly high abundance (up to 30%) of polyphosphate-accumulating organisms (PAOs) in the rhizosphere and their distinctive variations in different biosolid amendments. Furthermore, the interactions between EBPR-derived PAOs such as Candidatus Accumulibacter phosphatis and soil native plant growth promoting rhizobacteria highlighted the previously overlooked status and yet-to-be-characterized functions of PAOs in P cycling. This study provides a novel perspective leveraging EBPR biosolids to facilitate plant growth with agronomic benefits, thereby contributing to more sustainable and ecologically responsible agricultural practices.

The Rhizosphere Microbiome of Ginseng

The rhizosphere of ginseng contains a wide range of microorganisms that can have beneficial or harmful effects on the plant. Root exudates of ginseng, particularly ginsenosides and phenolic acids, appear to select for particular microbial populations through their stimulatory and inhibitory activities, which may account for the similarities between the rhizosphere microbiomes of different cultivated species of Panax. Many practices of cultivation attempt to mimic the natural conditions of ginseng as an understory plant in hilly forested areas. However, these practices are often disruptive to soil, and thus the soil microbiome differs between wild and cultivated ginseng. Changes in the microbiome during cultivation can be harmful as they have been associated with negative changes of the soil physiochemistry as well as the promotion of plant diseases. However, isolation of a number of beneficial microbes from the ginseng rhizosphere indicates that many have the potential to improve ginseng production. The application of high-throughput sequencing to study the rhizosphere microbiome of ginseng grown under a variety of conditions continues to greatly expand our knowledge of the diversity and abundance of those organisms as well as their impacts of cultivation. While there is much more to be learnt, many aspects of the ginseng rhizosphere microbiome have already been revealed.