Andres SE, Emery NJ, Rymer PD, Powell JR. Soil chemistry and fungal communities are associated with dieback in an Endangered Australian shrub.
PLANT AND SOIL 2023;
483:47-70. [PMID:
36211803 PMCID:
PMC9525234 DOI:
10.1007/s11104-022-05724-7]
[Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 09/23/2022] [Indexed: 05/08/2023]
Abstract
BACKGROUND AND AIMS
Field surveys across known populations of the Endangered Persoonia hirsuta (Proteaceae) in 2019 suggested the soil environment may be associated with dieback in this species. To explore how characteristics of the soil environment (e.g., pathogens, nutrients, soil microbes) relate to dieback, a soil bioassay (Experiment 1) was conducted using field soils from two dieback effected P. hirsuta populations. Additionally, a nitrogen addition experiment (Experiment 2) was conducted to explore how the addition of soil nitrogen impacts dieback.
METHODS
The field soils were baited for pathogens, and soil physiochemical and microbial community characteristics were assessed and related to dieback among plants in the field and nursery-grown plants inoculated with the same field soils. Roots from inoculated plants were harvested to confirm the presence of soil pathogens and root-associated endophytes. Using these isolates, a dual culture antagonism assay was performed to examine competition among these microbes and identify candidate pathogens or pathogen antagonists.
RESULTS
Dieback among plants in the field and Experiment 1 was associated with soil physiochemical properties (nitrogen and potassium), and soil microbes were identified as significant indicators of healthy and dieback-affected plants. Plants in Experiment 2 exhibited greater dieback when treated with elevated nitrogen. Additionally, post-harvest culturing identified fungi and other soil pathogens, some of which exhibited antagonistic behavior.
CONCLUSION
This study identified candidate fungi and soil physiochemical properties associated with observed dieback and dieback resistance in an Endangered shrub and provides groundwork for further exploring what drives dieback and how it can be managed to promote the conservation of wild populations.
SUPPLEMENTARY INFORMATION
The online version contains supplementary material available at 10.1007/s11104-022-05724-7.
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