Soil microbial community restructuring and functional changes in ancient kauri (Agathis australis) forests impacted by the invasive pathogen Phytophthora agathidicida. (November 2020)

• Record Type: Journal Article
• Authors: Byers, Alexa-Kate; Condron, Leo; O'Callaghan, Maureen; Waipara, Nick; Black, Amanda
• Is Part Of: Soil biology and biochemistry. Volume 150(2020)
• Publication Date: 2020-11
• Subjects: Soil borne pathogen -- Soil microbial communities -- Soil microbial function -- Disease suppressive soils -- Secondary disease impacts; Soil biochemistry -- Periodicals; Soil biology -- Periodicals; Sols -- Biochimie -- Périodiques; Sols -- Biologie -- Périodiques; Sols -- Microbiologie -- Périodiques; Bodembiologie; Biochemie; 631.46
• DOI: 10.1016/j.soilbio.2020.108016
• Languages: English
• ISSNs: 0038-0717

Abstract

Abstract: New Zealand's culturally iconic, ancient kauri ( Agathis australis ) forests are threatened with extinction as a result of dieback caused by an invasive and highly virulent soil-borne pathogen ( Phytophthora agathidicida ). Kauri trees function as a foundation species in their forests, supporting an ecologically distinct plant and soil environment. The impacts of disease outbreak and subsequent tree dieback on kauri forest ecosystems, in particular soil microbial communities, remains unknown. Using high throughput amplicon sequencing and GeoChip 5 S microarray analysis we analysed the differences in diversity, taxonomic composition and functional genes related to C and N cycling of soil microbial communities associated with asymptomatic and symptomatic mature kauri. Our results found significant differences in the fungal diversity and both fungal and bacterial community composition between asymptomatic and symptomatic kauri. Several microbial taxa known in the literature for their roles in disease suppression, such as Penicillium, Trichoderma, Enterobacteriacae and Pseudomonas, were identified as being significantly higher in asymptomatic kauri soils. These findings have provided a promising direction for the discovery of disease suppressive microbial taxa against kauri dieback. In addition, the composition and abundances of microbial genes related to C and N cycling also differed significantly. These findings highlight the potential long term impacts that dieback disease may have on the health and functioning of kauri forests. Highlights: Kauri dieback disease expression alters forest soil microbial diversity and composition. Microbial taxa related to disease suppression found higher in asymptomatic kauri soils. Functional microbial genes related to soil C and N cycling are impacted following dieback. Findings guide the identification of soil microorganisms which could be used as biocontrol agents against kauri dieback.