Amend Lab | Univ of Hawaii

Research

I. Diversity and Evolution of Fungal Endophytes in Native Hawaiian Plants

Found inside the healthy leaf tissue of every plant species yet examined, foliar fungal endophytes have been shown to play a critical role in mediating how hosts interact with their abiotic environment and with other organisms. Though invisible to the naked eye, endophytic fungi form ubiquitous and hyperdiverse communities spanning hundreds of millions of years of evolutionary history. It is suspected that these cryptic symbionts comprise a large portion of the estimated 98% of fungal species diversity that remains undocumented.

Combining culture-based methods, next-generation environmental sequencing and stored banks of genomic DNA from critically endangered (and extinct) species, we plan to survey foliar fungal endophyte communities from every habitat on each major island in the Hawaiian archipelago, including at least a single representative of most of the 165 native eudicot genera. Plants from two of Hawaii’s most species-rich adaptive radiations will be sampled near-completion to enable insight into evolutionary aspects of host-symbiont dynamics. 

Ultimately we hope to develop phylogenetic hypotheses for Hawaiian endophytic fungi and their plant hosts in order to study the evolution of specificity among endemic symbionts.

Hawaiian plantHawaiian plant

II. Biogeography of Small Organisms

Despite the longstanding dogma that “everything is everywhere, but the environment selects” in microbial biogeography, very few studies have actually tested this directly.  Our work examines the roles that reproductive strategy, dispersal limitation and environmental selection (such as temperature or moisture tolerance) play in shaping population structure, species ranges and community composition.  We’ve worked at scales ranging from centimeters to continents, including the oceans between them. 

pink flowersplant

 

III. Linking Evolution to Ecosystem Function

Soil fungi provide many ecosystem services including symbiotic interactions with plants and decomposition of complex carbon sources like lignin, cellulose and chitin.  Predicting how soil fungi will respond to changing climates is an important question for understanding future nutrient cycling rates. Because there are probably millions of soil fungal species, however, it is difficult to predict how any single fungus will fare in future climates.  To make this problem more tractable, we make use of the fact that the more closely related are two species, the more similar will be their response to global change.  By combining phylogenetic information about evolutionary relationships with field and microcosm manipulation experiments, we can better understand how shifts in soil fungal communities will affect our changing world.

field station
field station

IV. Microbial Diversity and Thermal Tolerance in Reef Building Corals

While researchers have focused considerable attention on fungal symbioses in terrestrial systems, marine fungal symbioses have remained largely unexamined.  Corals have long been portrayed as a model mutualistic symbiosis consisting in a colonial invertebrate and a photosynthetic dinoflagellate.  Our recent research has shown that microbial diversity within corals contains a surprisingly high diversity fungi that are distinct from those located in the adjacent water column.  We are interested in how these fungal communities are structured and whether they mediate the interaction between the coral and warming oceans.

acroporapetri dishes 

V. Diet and Conservation of the Endangered Tree Snail, Achatinella Mustelina

Achatinella mustelina is one of several tree snail species in an genus endemic to Oahu that make up a spectacular adaptive radiation.  Multiple labs and  agencies are working to conserve this species via predator exclosures, captive breeding programs and population modeling.  We are using high-throughput sequencing technology to assess the fungal diet of this species, and how this varies across sites and among host plants.

tree snail 

Data Download

Coral-associated marine fungi form novel lineages and heterogeneous assemblages

Data published in ISME Journal, 2012

Download file

Indoor fungal composition is geographically patterned and more diverse in temperate zones than in the tropics

Data published in PNAS, 2010

Download file