Urease producing microorganisms under dairy pasture management in soils across New Zealand

Urea, the most commonly used nitrogen fertiliser in New Zealand, can be quickly lost from the system via ammonia volatilisation or nitrate leaching following hydrolysis of urea by urease producing soil microorganisms (UPSMs). This study investigated UPSMs involved in urea degradation for upcoming research to reduce soil urease activity. Soils from under dairy pasture management across New Zealand, with a pasture species component of ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) and aged between 9 months to 60 years old, were collected, and UPSMs were isolated and identified using both polymerase chain reaction (PCR)-based molecular and conventional methods. The fungal genera belonged to diverse taxonomical groups including the phylum Ascomycota: class: Dothideomycetes, Eurotiomycetes, Leotiomycetes and Sordariomycetes, the phylum Basidiomycota: class: Tremellomycetes and the phylum Zygomycota: order: Mucorales, all of which have a role in urea degradation in soil. Pasture soil-resident urease producing bacteria belonged to the Gammaproteobacteria and Betaproteobacteria. Cupriavidus sp. and Mucor hiemalis showed strong urease activity when cultured on urease medium. This is the first report on the urease activity of the pasture soil inhabitants Pochonia bulbillosa, Mariannaea elegans and Gliomastix sp. This study was part of a larger study underway to investigate control of UPSMs in soil to improve the efficiency of urea utilisation

Research priorities for harnessing plant microbiomes in sustainable agriculture

Feeding a growing world population amidst climate change requires optimizing the reliability, resource use, and environmental impacts of food production. One way to assist in achieving these goals is to integrate beneficial plant microbiomes-i.e., those enhancing plant growth, nutrient use efficiency, abiotic stress tolerance, and disease resistance-into agricultural production. This integration will require a large-scale effort among academic researchers, industry researchers, and farmers to understand and manage plant-microbiome interactions in the context of modern agricultural systems. Here, we identify priorities for research in this area: (1) develop model host-microbiome systems for crop plants and non-crop plants with associated microbial culture collections and reference genomes, (2) define core microbiomes and metagenomes in these model systems, (3) elucidate the rules of synthetic, functionally programmable microbiome assembly, (4) determine functional mechanisms of plant-microbiome interactions, and (5) characterize and refine plant genotype-by-environment-by-microbiome-by-management interactions. Meeting these goals should accelerate our ability to design and implement effective agricultural microbiome manipulations and management strategies, which, in turn, will pay dividends for both the consumers and producers of the world food supply