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JTGP collaborator Chris Smith profiled on Tucson.com

Tucson.com, the online edition of the Arizona Daily Star, has a big new profile of Joshua Tree Genome Project collaborator, and now lead PI on the collaborative NSF grant supporting the project, Chris Smith. Smith grew up in Tucson and earned his undergrad degree at the University of Arizona, and the article goes in-depth on his longtime love of desert landscapes and the organisms that make a living in them:

Smith’s early work focused on yucca plants in isolated desert mountain ranges known as “sky islands” and the cactus longhorn beetle, a strange flightless bug that feeds on prickly pear and cholla in northern Mexico and the Southwestern U.S.

Then he met renowned evolutionary biologist Nils Olof Pellmyr, who steered him toward the fascinating bond between Joshua trees and the highly specialized yucca moths that live on them.

(“Olle” Pellmyr, who passed away in 2017, also mentored JTGP collaborators Jim Leebens-Mack and Jeremy Yoder.)

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LISTEN: Collaborators Chris Smith and Jeremy Yoder on Nevada Public Radio

Joshua Tree Genome Project collaborators Chris Smith and Jeremy Yoder were on today’s episode of Nevada Public Radio’s “State of Nevada” news show, talking Joshua tree history, natural history, and genomics with host Doug Puppel. You can catch the rebroadcast of the episode tonight at 7pm, or stream the segment on demand on the KNPR website.

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The Joshua Tree Genome Project gets big boost with NSF funding

Joshua trees in Tikaboo Valley, Nevada (Jeremy Yoder)

New collaborative grants from the National Science Foundation will support the Joshua Tree Genome Project in studying how one of the most distinctive plants in the Mojave Desert has adapted to the drought and heat of its home range, how extreme desert climates shape the trees’ peculiar relationship with pollen-carrying moths, and how the genetic information within genomes is re-organized over millions of years.

The grants to Willamette University and California State University Northridge, totaling more than $1.5 million, will pay for the assembly of a Joshua tree reference genome and extensive tests of Joshua tree seedlings in experimental gardens. From this, it will be possible to identify genes that help the trees cope with different climate conditions, and pinpoint how different environmental factors have affected their evolution. To conduct the work, the grants will support research experiences for undergraduate students and interns, graduate student thesis projects, and the expansion of a pilot program in which community volunteers across the Mojave learn to map and monitor Joshua tree populations in their own backyards.

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Watch JTGP collaborators discuss the project’s progress, and where it’s headed

Last week, Joshua Tree Genome Project collaborators Chris Smith and Jeremy Yoder spoke in a webinar series given by the Joshua Tree National Park Association’s Desert Institute. The talk ended up being a good overview of our plans for the JTGP, as well as an update on the work of assembling a Joshua tree reference genome. So when the Desert Institute posted the video on their YouTube channel, we thought we’d share it here:

Enjoy! And check out the rest of the Desert Institute video catalog, which includes all sorts of great natural history about Joshua Tree National Park and the Mojave Desert.

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“Wait, how many branches was that?” — Community monitoring of Joshua trees launches with leadership training

Earlier this month, community members from across the Mojave Desert came together at the Transitions Habitat Conservancy field station in Puma Canyon in the desert hills above Wrightwood, California, with a deceptively simple mission: to figure out how to count Joshua trees.

The volunteer leaders — from the California Native Plants Society, the Mohave Desert Land Trust, and the Transitions Habitat Conservancy — spent the Veteran’s Day weekend at Puma Canyon to learn a protocol for demographic surveys of Joshua tree populations, guided by Willamette University Associate Professor of Biology Chris Smith and his collaborators on the Joshua Tree Genome Project, US Geological Survey ecologist Todd Esque and CSU Northridge Assistant Professor of Biology Jeremy Yoder

USGS ecologist and JTGP collaborator Todd Esque explains how the challenges faced by Joshua tree at different stages of its life cycle. (Photo by Jeremy Yoder.)
USGS ecologist and JTGP collaborator Todd Esque explains the challenges faced by Joshua tree at different stages of its life cycle. (Photo by Jeremy Yoder.)
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Seeking Partners For Community Science

Volunteers set out for a survey of trees in Tikaboo Valley, Nevada (Photo: Chris Smith)

Volunteers set out for a survey of trees in Tikaboo Valley, Nevada (Photo: Chris Smith)

The Joshua Tree Genome Project and its partners are excited to announce a new community science program: Mapping Joshua Trees for Climate Change Resilience.

Working with local conservation organizations and teams of community scientists, we will develop a comprehensive map of the current distribution of Joshua trees, and assess population health through on-the-ground demographic surveys. The results of this study will allow us to develop a conservation plan for Joshua trees in the face of climate change. We are currently seeking local leaders from communities across the Mojave Desert to assist us with the project, and will hold a series of training events beginning in November, 2018.

To request more information, or become involved as a community scientist or a conservation leader click here and fill out the registration form.  For more information, keep reading.

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Return to Tikaboo Valley

Sunset over the contact zone (Jeremy Yoder)

We had a whole aisle to ourselves at the Henderson, Nevada, Super Wal-Mart. The shopping list for a month of desert fieldwork with a team of up to twenty filled half a dozen shopping carts — apples and oranges by the five-pound bag, piles of potatoes and pasta and oatmeal, twenty-five dozen eggs, three different kinds of Oreos, dishes and five-gallon water jugs and an extra folding table. We stacked it all in a rental RV, and the next morning we drove north.

For years, JTGP collaborator Chris Smith has organized trips to Tikaboo Valley, a site at the northernmost end of the Mojave Desert where the two species of Joshua tree meet. Over the course of each flowering season, Chris leads a team of Willamette University students, field staff, out-of-town collaborators, and willing volunteers in an ongoing experiment to understand how the trees match two different, highly specialized, pollinator species. Tikaboo provides a natural “common garden” where it’s possible to swap the pollinator species between the two Joshua trees, to see how things work out for all of them.

I drove up from Los Angeles to join Chris and his advance team in setting up camp in advance of the arrival of more than a dozen Willamette students for this week’s spring break. I was sorry to head back before things got properly underway, but I had a couple days to spend with the team scouting for flowering trees — a fine tour of Tikaboo Valley at the very beginning of spring.

Click on the gallery below to scroll through some images of the trip!

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How association genetics can find genes that help Joshua trees beat the heat

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Joshua trees in Tikaboo Valley, Nevada (jby)

This post is by JTGP collaborator Jeremy Yoder, an Assistant Professor in the Department of Biology at California State University, Northridge, who studies ecological and evolutionary genetics.

Since we first launched the Joshua Tree Genome Project, we’ve told you that one big reason we want to sequence a Joshua tree genome is to find genes that are important for adaptation to climate, which could help us makes sure that Joshua trees survive and thrive in a climate-changed future. But we haven’t discussed in detail how we’ll find those climate-adapted genes. The key to that part of the project is association genetics, a method for sifting through the genome to find the parts that contribute to traits we care about.

Figure 1. An example of a “candidate gene” experiment testing whether different diploid genotypes are associated with different trait values, or phenotypes. Points are the phenotypes of individual trees, grouped by their diploid genotypes at a candidate gene; overlaid box plots show that trees with different genotypes differ strongly in their phenotypes. (jby)

To understand how association genetics works, first consider a case in which we already know of a gene that might be important for a particular Joshua tree trait, like height or flower shape or physiological performance — or even just growing in places that are hotter or cooler. To figure out whether different variants in the sequence of our “candidate gene” are related to differences in the trait, we could measure the trait in many trees and then sequence that gene in all of those trees. We would test the hypothesis that the gene shapes the trait by comparing the trait values of trees carrying different variants of the gene sequence. Figure 1 gives an example of what this might look like in a hypothetical case, with tree phenotypes plotted against diploid genotypes at our candidate gene — “homozygous” trees carrying two copies of the G variant have higher phenotype values than homozygous trees carrying two copies of the A variant, and “heterozygous” trees with one copy of each have intermediate phenotypes. In this case, we’d probably conclude that the candidate gene has some effect on the phenotype we decided to measure, because different variants of the gene are associated with significantly different phenotype values.

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Plant physiology, the key to understanding how Joshua trees could adapt to a warming world

Karolina Heyduk is a postdoctoral researcher at the University of Georgia, and a co-PI on the Joshua Tree Genome Project. Karolina studies comparative genomics and the physiology of photosynthesis (Karolina Heyduck)

This is a post by JTGP collaborator Karolina Heyduck, a postdoctoral researcher at the University of Georgia.

Our Joshua tree proposal has been submitted to the National Science Foundation! Now we wait to hear if we’re granted to green light to study sources of adaptation in these remarkable desert species.

So what does “adaptation” mean anyway?

Adaptation refers to the process by which species over time acquire traits that allow them to succeed in a given habitat. A habitat includes both biotic elements – herbivores, pollinators, and pathogens – as well as abiotic phenomena like water availability, nutrients, light intensity, and temperature. Our research team is interested in both aspects. We suspect both pollinators and environment (temperature and water availability) are playing a role in Joshua tree speciation and adaptation, but we hope to test this with help from the NSF. Plant species that have become especially adapted to their environment didn’t arise in a single generation; instead, over many years, plants have passed down traits to their offspring that allowed these species to survive and thrive in tough conditions. However, when these abiotic environments change quickly – for example, due to climate change – plants may not be able to adapt fast enough, especially if they are long-lived with many years between generations.

For Joshua tree, which can live over 100 years, adapting to their changing climate will be critical to their survival. Joshua trees are already showing signs of trouble (check out this National Geographic article on them), and the Mojave is only expected to become warmer, forcing Joshua trees to either adapt or die. Currently Joshua trees are found across both high elevation (cooler) and lower elevation (warmer habitats). In both of those elevational levels, we also find Joshua trees in drier and wetter habitats. We might hypothesize that those Joshua trees already found in the hottest and driest habitats might survive best in the future, but we simply do not know. One big goal of our NSF grant will be to screen populations from different habitat types for traits that will help them succeed in the changing Mojave. But how do we do that?

We will measure chlorophyll fluorescence with a fluorometer to determine photosynthetic efficiency and overall plant stress. (Wikimedia Commons: Felipe Jo)

Our first step will be to collect seeds from different populations across both high/low elevations and with varying degrees of rainfall. We will grow these seedlings and plant them in gardens across the Mojave desert. Once they stabilize, we begin screening them for a long list of characteristics relating to water use efficiency and photosynthesis – two huge traits when it comes to desert survival. Water use efficiency refers to how much water a plant loses for every molecule of CO2 is gains. Plants take in CO2 through their open stomata, tiny pores on the surface of the leaf, but stomata also allow water vapor to escape from the leaves. This loss of water to the atmosphere is important for plants to pull water from the soil, forming a suction force like when you drink from a straw, but too much water loss in the desert can be deadly. Plants can minimize water loss by closing stomata, but this must be balanced by the need to take in atmospheric CO2 for sugar production. Photosynthesis is also important for plant survival, but can be impaired by extreme temperatures and a lack of water (Figure 1).

Measuring these traits will take us a while, and can only be done with the help of both undergraduate students and citizen scientists. Once we’re done measuring our traits of interest, we can begin to determine which Joshua tree populations are most flexible – and therefore might be the quickest to adapt – to changing environmental conditions. Understanding how Joshua tree physiology interacts with their habitat is critical for our understanding of how to help this magnificent species persist into the future

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By Invitation Only: The Next Step in Funding the Joshua Tree Genome Project

Hard at work on the full proposal. (CIS)

Back in January we wrote to you about preparing a proposal for the National Science Foundation. Now, we have some encouraging news to share.

Don’t break out the champagne yet though.

Last month we received the good news that our proposal had been ‘invited for a full proposal’.

As research funding has become more and more competitive, the National Science Foundation has turned to using ‘preliminary proposal’ system. Each January scientists from around the country put together short summaries of their latest and greatest research ideas. From the hundreds of preliminary proposals they receive, about eight dozen (approximately 25%) will be invited to submit a full proposal.

And (drum roll, please!) our proposal was one of the lucky ones invited to prepare a longer form description of our research proposal. So, while the rest of you are out enjoying the summer sun (or hiding from triple digit heat if you live in the Mojave), here at the Joshua tree genome project we’ve been hard at work trying to make the best possible case for our work. In a little less than a week we will send off our full proposal. And then we will wait …

We probably won’t hear a final funding decision until December at the earliest, and statistically, our chances are slim. But, at the moment, our thoughts are occupied with all the things that we will do if we were funded.

Here is a partial list of what we have in mind:

  • Completing, assembling, and annotating the full Joshua tree genome
  • Surveying genetic diversity across the entire range of the Joshua tree
  • Common garden experiments to identify genes involved in climate adaptation
  • An expanded citizen science program with Cal Native Plants
  • Public Lectures at the Desert Institute
  • Research internships for underrepresented minority students
  • Outreach to public school teachers in southern California

It’s a long and ambitious list. We hope that it’s enough to make our work stand out. Wish us luck!

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