[Plsfaculty] Brooke Sykes, Dissertation Defense, Monday, 4 August, 10 AM Marley 230

[Mark A Beilstein]

Please join us on Monday, August 4th at 10:00 AM in Marley 230 when Brooke
Sykes will defend her PhD Dissertation titled “Temporal, spatial, and
phylogenetic factors that structure foliar fungal endophyte communities
across scales.”


You may also attend virtually at:
https://arizona.zoom.us/j/6254403122?omn=85445796521
<https://www.google.com/url?q=https://arizona.zoom.us/j/6254403122?omn%3D85445796521&sa=D&source=calendar&usd=2&usg=AOvVaw053ny5JDb1KsOE5Gy_jQCU>

Password: Fungi


Abstract: Fungal symbioses are an ancient and essential component of plant
life in the terrestrial landscape. Foliar fungal endophytes, which occur
within photosynthetic structures of all plants, play key functional roles
in enhancing plant health and resilience. In studies that link genetic
variation, phylogenetic structure, and aspects of environment, I seek to
define factors that shape the communities of these hyperdiverse and
understudied symbionts. First, I test hypotheses about community assembly
at a small spatial scale, considering the interplay of hosts’ genetic
variation and microenvironmental factors. My collaborators and I show that
environmental factors, especially relevant to stress, are important in
defining the endophyte communities in North America’s most endangered
conifer. I next consider the degree to which coevolution has shaped
communities of endophytic fungi, with a focus on gymnosperms. My
collaborators and I show that endophytes of gymnosperms vary regionally and
do not exhibit strong evidence of phylosymbiosis at a deep phylogenetic
level. However, endophytes in some families (Pinaceae, Podocarpaceae)
recapitulate their hosts’ phylogeny and have conserved associations with
different fungal classes, highlighting the importance of host genetic
background to endophytes worldwide. Recognizing the need to encompass
timelines beyond the present, in my third chapter I focus on the potential
for dried plant specimens, housed in herbaria, to serve as time capsules of
endophyte diversity. Against the backdrop of the rapidly changing Arctic,
my collaborators and I use historical plant collections to observe
endophyte diversity and host affiliations over the past century. I show
that both in the present day, and over collections made from 1886 to 2024,
Arctic endophytes are diverse and climate-sensitive. Taken together, my
work scales from nurseries to continents to characterize these fundamental
symbioses over time, geography, and evolutionary history.
___________________
Mark Beilstein, Ph.D.
Associate Professor
Director of Graduate Studies
Bart Cardon Fellow
School of Plant Sciences
P.O. Box 210036
Forbes Building, Room 303
Tucson, AZ 85721-0036
mab-lab.org
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