All posts by Jason Stajich

About Jason Stajich

Assistant Professor, UC Riverside

ZyGoLife visitors

Last week we hosted several visitors from our ZyGoLife collaborative team in sunny California. I wrote a few notes on Nicole Reynolds and Javier Tabima’s visit for the zygolife site on their extended research stay. We also got to host the Zygofornia Zygolife team meeting.  Here are some pictures I took from the desert and mountain visits.

Zygolife team photo, minus Jason, in the UC James Reserve, San Jacinto Mountains, California
Lost in a forest? Or finding fungi? in the James Reserve, San Jacinto Mountains
bees love the water near a wash that had a little bit of moisture in Mojave, in Granite Mountain Desert Research Center
Jessie and Derreck bonded over fungi and bacteria
Lichens and mosses on granite rocks in Granite Mountain Desert Research Center
Sunset over Kelso Dunes in Mojave National Preserve
Lizards in Mojave National Preserve
Blooms among Lava in Mojave National Preserve
Sweeny Granite Mountain Desert Research Center, a University of California, Natural Reserve.

Kelso Dunes, Mojave National Preserve

Desert Adventures, 2018

Nat and Jason headed out to the Mojave National Preserve to meet up with Erik Hom and his StudyUSA class from Univ of Mississippi. We started at the Sweeney Granite Mountains Desert Research Center which is one of 39 Natural Reserves in the University of California.  We were there to teach a bit about cryptogamic crusts, show the Kelso dunes off, and explore some more of the desert crust sampling sites that our collaborator Nicole Pietrasiak (@drylandalgae) and Paul De Ley have collected from. Nothing like seeing sites that previously I only knew from pictures or tubes of soil!

A few pictures from our visit.

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Kelso Dunes
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Crusts symbioses of algae and cyanobacteria with fungi, bacteria, and many uncounted single celled organisms.

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Lichen Crusts galore across from the Kelso dunes
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Moss Crusts are also rich symbioses with a predominant moss.
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Old volcanic flow in the Cima area also has cacti and crusts
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Colorful lichens found on the granite faces. On closer looks, these are often 3 or more species competing for space on the same surface.

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The Joshua Tree Album

Our lab trip to Joshua Tree NP and photo session before the start of the quarter resulted in our 2017 album cover lab photo.

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We also visited one of Julia’s field sites where she is working on a lichen biodiversity inventory and some comparison of the genetic diversity of the fungi and algae symbiont along an elevation gradient in the park.
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Derreck is excited to collect some dung samples that may recover some zygomycete isolates for the Zygolife project. StajichLab-1-31

The rest of pictures from the day are in this flickr album.

Welcome new graduate students Tania and Julia

Welcome to first year graduate students Julia Adams (Plant  Biology) and Tania Kurbessoian (Microbiology). Tania joins us after completing a MS in Microbiology at Cal State-Northridge. She will starting out work on projects relating to genomics and physiology of extremophilic fungi,  black yeasts and efforts to culture and describe diversity of desert fungi. Julia completed a BS at Wellesley and has worked on a variety of projects related to lichen fungi. She will focus on lichen fungi from desert regions and will use genomic and potentially metabolomic tools to study evolution and unique properties of some lichenized fungi endemic to Joshua Tree National Park and the Mojave desert.

Congrats Nat on passing qualifying exam

Congrats to Nuttapon (Nat) who passed his qualifying exam this week and is now a PhD Candidate. Along with Derreck he is the second Plant Pathology graduate student in the lab and is working towards his PhD on microbial diversity of cryptogamic or biological soil crusts found in the desert. His primary research area is Joshua Tree National Park and desert areas in the UC Reserve System. Nat and Jason have benefited greatly from collaboration with New Mexico State Univ Professor Nicole Pietrasiak who is an expert in crusts, desert algae, and did her PhD work in Joshua Tree which harbors tremendous diversity of biological soil crust types.

Biological Crust
Cross section of crust. Image by N. Pietrasiak

 

Chytrid Opsin structure paper published

Great work by former graduate student Steven Ahrendt (@sahrendt0), visiting student and current Duke graduate student Edgar Medina (@WhippingFungi) on the publication of a manuscript describing a Type II Opsin found in the zoosporic fungi.  “Exploring the binding properties and structural stability of an opsin in the chytrid Spizellomyces punctatus using comparative and molecular modeling” in PeerJ! Thanks also to co-author and collaborator Chia-en Chang in Chemistry Dept at UCR who helped mentor Steven on homology modeling and docking analyses. I also learned a lot through this project and was excited to be able to merge evolutionary and computational approaches. The project lead to the surprising findings of a gene important for light sensing that is shared among just the zoosporic (fungi with a flagellate life stage) and animals.

This project has been going for a while … Edgar and I discovered this protein in ~2008 when we started independently analyzing the Batrachochytrium genome, the first chytrid fungus sequenced. Based on sequence similarity we realized it looked like an animal rhodopsin, a 7 transmembrane G-protein coupled receptor (GPCR). These rhodopsins are called type II opsins and typically respond to green light.  We went looking for this in the first place because of work published in 1997 from Ken Foster’s lab which showed that zoosporic chytrid fungi respond to green light and that likely this behavior is due to a rhodopsin or rhodopsin-like GPCR  We found longer intact copy in the genome of the chytrid S. punctatus, so decided to focus on that copy – though we later discovered additional modifications of the predicted gene structure appeared necessary. We decided to do some homology modeling with the solved structure of a squid rhodopsin as shown in Figure 1. This confirmed that the sequence was compatible with the Type II Opsin structure. The paper documents several other computational simulations to test for the likely binding chromophore and hypothesis testing about the stability of the protein structure. Overall this work provides confidence that the sequence encoded in the genome of the zoosporic fungus can fold into a structure compatible with an opsin.

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Figure 1A: Structural alignment of S. punctatus homology model (grey) with T. pacificus crystal structure (light purple)

It still remains to be tested if this opsin-like gene can biochemically function in this way. We hope to explore more of that with some additional work in the future. We have also nearly completed our manuscript analyzing the evolutionary history of this protein in fungi and related species to give a better picture of the timing of the emergence of this receptor-like protein. This project has helped advance some ideas about how zoosporic fungi interact with their environment based on genomic and computational analyses. This gene is a good candidate for future investigations into environmental sensing and signaling in zoosporic fungi.

Asilomar and beyond

Just back from another fantastic Fungal Genetics Conference at Asilomar. An amazing number of helpful tweets under the #Fungal17 hashtag. Sarah Unruh (@sau916) and I are talking about how to best archive or building a storify this so it is easier to read. Always a fun meeting to see friends and nosh at the smorgasbord of fungal genetics, epigenetics, genomics, ecology, evolution, and chemistry that is going on. Jason got to give a Plenary talk and express the utility of sequencing fungal genomes in studying their evolution. Lab Alumnus Steven Ahrendt won a poster award on his work on Cryptomycota fungi and also gave a talk. 


Also got some good news that our paper on structural analyses of a rhodopsin-like protein in the chytrid fungi has been accepted at PeerJ after some helpful revisions – (see the preprint).

Onward!