Biology subjects

Buss, W.

Publications and source records attributed to Buss, W..

3 recordsLinked to original sources

bioRxiv2023

Stabilisation of soil organic matter with rock dust partially counteracted by plants

Soil application of Ca- and Mg-rich silicates can capture and store atmospheric carbon dioxide as inorganic carbon but could also have the potential to stabilise soil organic matter (SOM). Synergies between these two processes have not been investigated. Here, we apply finely ground silicate rock mining residues (basalt and granite blend) to a loamy sand in a pot trial at a rate of 4% (equivalent to 50 t ha-1) and investigate the effects of a wheat plant and two watering regimes on soil carbon sequestration. Rock dust addition increased soil pH, electric conductivity and soil-exchangeable Ca and Mg contents, as expected for weathering, but decreased exchangeable levels of micronutrients Mn and Zn, likely related to soil pH. Importantly, it increased mineral-associated organic matter by 22% due to the supply of secondary minerals and associated sites for SOM sorption. Additionally, in the non-planted treatments, rock supply of Ca and Mg increased soil microaggregation that subsequently stabilised labile particulate organic matter as organic matter occluded in aggregates by 46%. Plants, however, reduced soil exchangeable Mg and Ca contents and hence counteracted the silicate rock effect on microaggregates and carbon within. We attribute this cation loss to plant exudates released to solubilise micronutrients and hence neutralise plant deficiencies. The effect of enhanced silicate rock weathering on SOM stabilisation could substantially boost its carbon sequestration potential when pH and micronutrient effects are considered.

plant biology↗

bioRxiv2022

An autoactive NB-LRR gene causes Rht13 dwarfism in wheat

Semidwarfing genes have greatly increased wheat yields globally, yet the widely used gibberellin (GA) insensitive genes Rht-B1b and Rht-D1b have disadvantages for seedling emergence. Use of the GA sensitive semidwarfing gene Rht13 avoids this pleiotropic effect. Here we show that Rht13 encodes a nucleotide-binding site/leucine-rich repeat (NB-LRR) gene. A point mutation in the semidwarf Rht-B13b allele autoactivates the NB-LRR gene and causes a height reduction comparable to Rht-B1b and Rht-D1b in diverse genetic backgrounds. The autoactive Rht-B13b allele leads to transcriptional upregulation of pathogenesis-related genes including class III peroxidases associated with cell wall remodelling. Rht13 represents a new class of reduced height (Rht) gene, unlike other Rht genes which encode components of the GA signalling or metabolic pathways. This discovery opens new avenues to use autoactive NB-LRR genes as semidwarfing genes in a range of crop species, and to apply Rht13 in wheat breeding programmes using a perfect genetic marker.

plant biology↗

bioRxiv2021

Soil organic carbon fractionation and metagenomics pipeline to link carbon content and stability with microbial composition - First results investigating fungal endophytes

Society needs to capture gigatons of carbon dioxide from the atmosphere annually and then store it long-term to limit and ultimately reverse the effects of climate change. Bringing lost carbon back into agricultural soils should be a priority as it brings the added benefit of improving soil properties. Linking soil organic carbon (SOC) fractions of different stability with soil microbial composition can help understand and subsequently manage SOC storage. Here we develop a pipeline for evaluating the effects of microbial management on SOC content using rapid and low-cost SOC fractionation and metagenomics approaches. We tested the methods in a wheat pot trial inoculated with 17 individual endophytic fungal isolates. Two fungi increased total SOC in the area under the plant stem by ~15%. The fractionation assay showed that the medium stability soil aggregate carbon fraction (AggC) was increased by one of these fungi (+21%) and the chemically recalcitrant proportion (bleach oxidation) of AggC by the other (+35%). Both fungi increased mineral-associated organic carbon (MAOC), the long-term SOC storage, by ~10%. We used rapid, portable, low-cost, whole metagenome long read sequencing to detect a shift in the microbial composition for one of the fungi-inoculated treatments. This treatment showed a more diverse microbial community and a higher quantity of DNA in soil. The results emphasise the link between composition and abundance of soil microorganisms with soil carbon formation. Our dual carbon fractional and metagenomic analysis pipeline can be used to further test the effects of microbial management and ultimately to model the soil factors that influence SOC storage, such as nutrient and water availability, starting SOC content, soil texture and aggregation.

genomics↗