|CHENG, LIANG - Cornell University - New York|
|GAN, HUIJIE - Cornell University - New York|
|WICKINGS, KYLE - Cornell University - New York|
|PETROVIC, MARTY - Cornell University - New York|
|KAO-KNIFFIN, JENNY - Cornell University - New York|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/22/2020
Publication Date: 7/26/2020
Citation: Panke-Buisse, K., Cheng, L., Gan, H., Wickings, K., Petrovic, M., Kao-Kniffin, J. 2020. Root fungal endophytes and microbial extracellular enzyme activities show patterned responses in tall fescues under drought conditions . Agronomy Journal. 10:1076. https://doi.org/10.3390/agronomy10081076.
Interpretive Summary: Maintaining or improving plant production systems and yield under drought stress conditions is, and will remain, a growing challenge into the foreseeable future. The communities of microorganisms, or microbiomes, in the rootzone of plants are an untapped resource for enhancing the drought tolerance of plants in the field. This work takes the initial step of looking at the identity and activity of soil microbial communities across multiple grass genotypes of varying drought tolerance to identify potential ecological trends and microbial mechanisms associated with drought tolerance. This work lays the foundation for leveraging microbial communities as a potential avenue for enhancing drought tolerance in plants.
Technical Abstract: Plant responses to abiotic stress can be altered by the soil microbial community, but its role in plant genotype-specific tolerance is unclear. We imposed drought conditions on 116 tall fescue genotypes using a rainout shelter, and then irrigated plots to stimulate drought recovery. Soil extracellular enzyme activities and microbial community profiles were assessed at three points: pre-drought, peak drought, and post-drought recovery. We hypothesized that rhizosphere microbial structure and function shift across different levels of drought tolerance in tall fescue, which would reveal potential microbial taxonomic and functional traits indicative of drought tolerance in the plant host. Bacterial 16S rRNA gene and fungal ITS sequencing showed shifts in microbial communities patterned across the pre-drought, peak drought, and post-drought recovery treatments, but microbial community structure was largely identical across drought tolerance levels. However, microbial function differed with potential chitinase and phenol oxidase activities increasing in rhizospheres of the most drought tolerant genotypes. Additionally, lower rates of dark septate endophyte infection in tall fescue roots were associated with the most drought tolerant genotypes. These observations suggest that taxonomic information from 16S rRNA gene and ITS sequences provided no indicators of microbial impacts on drought tolerance of the host plant, but microbial extracellular enzyme activities and root fungal infection methods revealed specific patterns across drought tolerance levels.