Abstract Detail

Mycology

Nash, Jake [1], Looney, Brian [2], Bleich, Andrew [1], Hameed, Khalid [1], Vilgalys, Rytas [1].

Populus root-associated fungal communities undergo strong and host-specific successional turnover.

Although most trees associate with either arbuscular mycorrhizal fungi or ectomycorrhizal fungi, a subset of tree species associates with both guilds of mycorrhizal fungi - termed "dual-mycorrhizal." Fungal communities colonizing dual-mycorrhizal plants often follow a predictable succession from dominance by arbuscular mycorrhizal fungi early in growth to dominance by ectomycorrhizal fungi as the plant develops. However, it is not well understood how temporal patterns of fungal colonization vary between dual-mycorrhizal plants or how individual fungal species vary in their temporal colonization patterns. We conducted a controlled growth experiment to understand 1) how the abundance of different root-associated fungal guilds differs by plant developmental stage, 2) how different species of Populus vary in their temporal patterns of root fungal association, and 3) how much variability there is between species of fungi in their successional patterns. We grew two species of Populus - P. tremuloides and - in microcosms inoculated with field soils from mature Populus stands and comprehensively characterized the root-associated fungi at seven and 12 months using long-read RNA sequencing of transcribed fungal 28S sequences. At 7 months, both species of Populus were dominated by endophytic fungi. By 12 months, colonization by endophytes sharply declined in both species, with P. trichocarpa becoming extensively colonized by arbuscular mycorrhizal fungi and P. tremuloides becoming dominated by ectomycorrhizal fungi with very sparse arbuscular mycorrhizal colonization. Prominent ectomycorrhizal taxa included Hebeloma, Tuber, Cenococcum, Ceratobasidium, Sebacina, Wilcoxina, and Hyaloscypha.  Arbuscular mycorrhizal fungal taxa included Glomus, Rhizophagus, Funneliformis, and Claroideoglomus. Despite the general trend of increasing dominance by ectomycorrhizal fungi on P. tremuloides, certain ectomycorrhizal fungi declined in abundance by 12 months, including Cenococcum and members of the Helotiales. These findings show that endophytic fungi can be important root-associated fungi and should be considered as a third fungal guild on Populus with unique successional dynamics. Our findings also show that even closely related dual-mycorrhizal plants can vary widely in their temporal patterns of fungal colonization. Further work will characterize changes in plant-fungal signaling through time by measuring small secreted proteins and lipochitooligosaccharides.

1 - Duke University, Biology
2 - Clark University, Biology

Keywords:
Populus
Mycorrhizae
PacBio Sequencing
Ectomycorrhizae
Arbuscular mycorrhizae
Endophytes
Mycology.

Presentation Type: Oral Paper
Session: MY4, Mycology: Endophytes, Communities, Hydrophobins, and Transporters
Location: /
Date: Wednesday, July 21st, 2021
Time: 1:15 PM(EDT)
Number: MY4004
Abstract ID:98
Candidate for Awards:MSA Best Oral Presentation Award by a Graduate Student