Abstract Detail

Mycology & Phycology

Sykes, Brooke [1], Crown, Jessie [1], Lutzoni, Francois [2], Renwick, Annabel [3], Skarha, Shannon [4], Arnold, A. Elizabeth [1].

Using an ex-situ conservation nursery to identify a core mycobiome in the endangered tree Torreya taxifolia.

Nurseries often serve as important sources of young trees for forestry and conservation purposes. Ex-situ nurseries for endangered plants can be especially important when plants in natural habitats are threatened by biotic or abiotic factors that limit their success in the wild. In conservation nurseries, botanical gardens, and arboreta, plants host diverse fungal symbionts, including rhizosphere symbionts and foliar endophytes. In natural settings, such fungi vary among plant species, change in composition under different environmental conditions, and interact closely with plant tissues, influencing plants’ resilience to stress, pathogens, and pests over ecological and evolutionary time. In nurseries, fungal symbionts may include distinctive taxa not known from other plants in the nursery area, consistent with seedborne transmission or introduction with seedlings at the planting stage. Alternatively, plants in such nurseries may acquire fungal symbionts characteristic of the nursery location, which may represent species with which they have little shared coevolutionary history due to geographic distance from the plant species’ native range. In the latter case we would expect (1) highly variable fungal communities among host individuals or genotypes in nursery settings, and (2) high similarity to fungal communities in plants occurring near the nursery site. To test these predictions we examined foliar endophyte and rhizosphere fungal communities in Torreya taxifolia (Taxaceae) in an ex-situ nursery. Torreya taxifolia has been critically endangered for over two decades following reductions in the small remaining wild population by a novel Fusarium pathogen. The nursery is located in a forested area in which extensive collections have characterized endophytes in diverse plant taxa over the past 20 years. We used culturing and high-throughput metabarcoding to characterize fungal communities in leaves and soil from multiple plants in each of three T. taxifolia genotypes. Consistent with our first prediction, foliar- and soil fungal richness and abundance varied markedly by individual: the number of fungal isolates, community composition of endophytes and soil fungi, and relative abundance of fungal taxa differed strongly from plant to plant. Consistent with our second prediction, endophyte communities contained many species known from other plant species in the area, with common endophyte genera of the region well represented in the T. taxifolia endobiome. However, we also detected several taxa in leaves of T. taxifolia that were distinct relative to those of diverse plants in the nursery region. We predict that these fungi are closely affiliated with T. taxifolia, potentially reflecting a shared evolutionary history and likely important in plant health. Overall, our data show that plants in conservation nurseries may acquire communities of symbionts that reflect the nursery area and surrounding plant communities. However, by distinguishing endophyte communities in nursery plants from those in plants that occur locally, it may be straightforward to detect a ‘core mycobiome’ affiliated with plants of conservation interest. Such a core mycobiome is likely unique, functionally important, and relevant to the conservation of its host species. Thus ex-situ conservation nurseries may be important tools for selecting and preserving important fungi relevant to the health and preservation of endangered plants.

1 - University Of Arizona, School Of Plant Sciences, 1140 E South Campus Drive, Forbes 303, Tucson, AZ, 85721, United States
2 - Duke University, Department Of Biology, Box 90338, Durham, NC, 27708, United States
3 - Duke University, Sarah P. Duke Gardens, 420 Anderson St., Box 90341, Durham, NC, 27708, USA
4 - Duke University, Department of Biology, Box 90338, Durham, NC, 27708, USA
5 - University Of Arizona, School Of Plant Sciences, 1140 E South Campus Drive, Forbes 303, Tucson, AZ, 85721, United States

Keywords:
plant-microbe
endophyte
mycology
nursery.

Presentation Type: Poster
Number: PMP004
Abstract ID:380
Candidate for Awards:None