Rhizosphere microbiome engineering for plant drought stress resilience using a fungal volatile organic compound

Abstract

Rhizosphere microbiomes have long played a crucial role in building plant resilience to environmental stressors such as drought. Fungal volatile organic compounds (FVOC) play a key role in plant-microbe interaction including host-microbiome recognition, assembly, and maintenance using chemical signals. This study investigated the impact of a FVOC on plant biomass and rhizosphere bacterial abundance of drought stressed pasture (perennial ryegrass and white clover) under glasshouse conditions. Rhizosphere samples were collected when plants had recovered from three consecutive drought events. Roots with rhizosphere soil firmly attached were placed in phosphate buffered saline and processed by shaking for 10 min, filtering using 100 μm cell strainers, and centrifuging for 5 min at 3000 x g. Bacterial genomic DNA was extracted using Qiagen DNeasy PowerSoil Pro Kits. The V5 and V7 regions of the 16S rRNA amplicons were sequenced using the DNA nanoball (DNB) sequencing platform, with sequence denoising using the DADA2 pipelines, and microbiome analyses conducted via MicrobiomeAnalyst. FVOC treatment increased plant dry weight 19% and 17% and rhizosphere soil bacterial population by 44% and 99% compared to the control, under well-watered and drought conditions, respectively. Three main bacteria genera, Thermoactinomyces, Laceyella, and Geobacillus, were 90%, 64%, and 107% respectively, more abundant in the FVOC treatment than the control. These three bacterial genera are involved in promoting plant growth and enhancing plant drought stress resilience. These results suggest that this FVOC can selectively manipulate beneficial microbial taxa in the rhizosphere to promote plant drought stress resilience, which could be a potential strategy for enhancing crop performance under drought conditions.