Cranberries are grown in sunken bogs that can be flooded to harvest the fruit. (photo by Vinson Doyle)
Plants and fungi have an intimate relationship. Some fungi, like mycorrhizal fungi which help a plant’s roots use soil resources more efficiently, are beneficial to plants, while others, like powdery mildew on squash leaves, are obviously harmful. However there are many fungi that exist somewhere on the continuum between friend and foe. To further complicate the matter, whether an individual fungus is beneficial, neutral, or antagonistic may change over time such that apparently harmless fungi can become pathogenic.
Cranberries infected with pathogenic fungi. Many different species of fungi are responsible for causing cranberry fruit-rot, but Colletotrichum is one of the most prevalent in cultivated cranberries. (photo by Vinson Doyle)
Studying these fungi can be difficult; they do not always make their presence obvious. Imagine tracking an elephant through the forests of East Africa to understand what it eats, where it travels, and how it selects a mate. Now, imagine tracking an individual you can’t see in the wild, or if you can see it, you can’t tell it apart from its siblings. Tracking these wild fungi would have been impossible a decade ago, but with the advances being made in modern genetic methods both here at The New York Botanical Garden and around the world, we are finally able to address the big questions surrounding these tiny organisms.
My work focuses on understanding the genetic diversity of a single fungal species, Colletotrichum gloeosporioides. C. gloeosporioides is a sneaky fungus that is capable of shifting its place on the continuum between harmless and pathogenic to cranberry. The main focus of my research involves understanding how the spores of C. gloeosporioides are dispersed, what other plants it is associated with, and how it reproduces. I hope that a fuller understanding of this fungus will help cranberry growers formulate effective management plans.
But before we can find answers we have to find the fungus.
Flowering cranberries. While these plants are healthy, there are fungi living under the surface of the plant tissue. (photo by Vinson Doyle)A pure isolate of Colletotrichum growing on agar that was isolated from cranberry. Ascospores produced in the laboratory by a Colletotrichum species isolated from cranberry. (photo by Vinson Doyle)
My field work begins in the cultivated and wild cranberry bogs of North America in the hope that by finding the plant, we will find the fungus. In some cases, it is readily obvious that the plants have been infected by a pathogenic fungus. However, we frequently can’t determine which fungus has infected them, so we collect fruits, stems, and leaves and bring them back to the lab for further study. In other cases, we find plants that look perfectly healthy, but we suspect there are fungi lurking beneath the surface. So we take the material back to the Pfizer Plant Research Laboratory for more research. The hunt continues!
In order to study plant-associated fungi, that is, fungi that live within a plant such as C. gloeosporioides does, we must first coax the fungi out of the plant. To do this we place the plant pieces on a suitable growth medium that encourages the fungus to emerge from the plant and to populate the medium; in this way we are able to isolate the fungus and study it more carefully. Inevitably, many different species of fungi emerge onto the growth medium, which means we must isolate and identify each one.
A high elevation cranberry bog in the Monogahela National Forest in West Virginia. Cranberries are in flower along the banks of the stream (photo by Vinson Doyle)
Once we have isolated all the individual fungal strains, we use methods similar to those used in forensics to identify each one. In the Cullman Lab, we use DNA markers that allow us to identify each individual fungal strain within a single species in the same way that forensics specialists use DNA markers to establish whether an individual was at the scene of a crime.
Modern genetic methods have helped us determine that fungal strains are likely moving undetected (disguising themselves as harmless fungi) inside cranberry vines used to establish new farms in disparate regions before revealing themselves as harmful pathogens. This finding will hopefully allow researchers and farmers in the future to better understand the sources of disease epidemics. This knowledge should help farmers implement preventative measures and may lead to new methods for establishing cranberry bogs.
Jonathan Billing is GreenSchool Science Education Intern.
The GreenSchool is a classroom and a laboratory for school groups from New York City and beyond, but it’s not just the students who are in for a treat. Teachers and chaperones are also likely to be delighted by any trip to the GreenSchool. The journey of discovery begins as you step into the incredible Enid A. Haupt Conservatory, wend your way through the fascinating houses, and emerge into the Deserts of the Americas. Descend the stairs and turn right, you’ll see a turtle petroglyph carved by the Lenape tribe, and a mysterious set of slatted green doors labeled, “GreenSchool.” Behind those doors lies a world of wonder and scientific exploration.
My name is Jonathan Billig and it is my honor and privilege to work as the GreenSchool Science Education Intern. I have been here for the last seven months, and in two more I’ll have to move on, to make way for another eager educator. He or she will learn how to use inquiry-based education, perform administrative tasks such as arranging the GreenSchool schedule, and do a lot of minute work for a very great cause; I’m about to prepare 300 bean sprouts for kindergarteners to pry open and observe in next week’s Life Cycle classes.
Our greatest resources at the GreenSchool are the curiosity of our students, our amazing instructors, and the living library that is The New York Botanical Garden. Classroom work is important, don’t get me wrong, but kids really blossom when they can put their learning into a living context. “What? A Kapok tree sends water to its leaves 250 feet in the air so that it can do photosynthesis?” “What are those lines on the leaves? Are they like the veins in our arms?” The varied environments of the Conservatory, and the diverse collections outside, provide a wealth of educational experience that students rarely forget.
In the three rooms of the Green School, instructors help students explore the scientific wonders of botany, gardening, ecology, and more. Students visiting the GreenSchool might practice microscope skills by observing an Elodea leaf at 400x, or examine the flowers, stems, seeds, roots and leaves that make up our botanical diet, like broccoli. “Broccoli is a flower!? And it tastes so good. This is changing my life!” That was said by a second grade boy from the Bronx.
The GreenSchool is at its best when you see kids connecting first-hand experience to advanced scientific concepts. We teach about the water cycle first by asking kids to observe where they notice water in the Conservatory, or where they think it might be. Then, through drawing, discussion, and explanation in our classrooms, we contextualize that information. It’s a wonder to see students begin to understand how water moves through every ecosystem, from a distant rain forest to a tiny apartment!
So the next time you see those mysterious green slatted doors, hopefully you will be with a school group so you can come in and learn with us. If not, rest assured that there’s a whole lot of wonder behind those doors, and a whole lot you can learn outside of the GreenSchool, no matter your age!
Rachel Meyer (left) and Natalia Pabon-Mora (right)
In the Genomics Program, curators, post-docs, graduate students, and technicians, along with undergraduate and high school interns are studying how genes make plants different from each other–for instance why the seeds of some species are enclosed in an edible fleshy fruit like a tomato, whereas the seeds of other species are surrounded by a pod (also called a capsule) that dries and splits open to release the seeds. Graduate students Natalia Pabon-Mora (Judith and Andrew Economos Fellow) and Rachel Meyer and I are studying what makes a tomato fleshy and edible rather than dry and woody by comparing the genes that are active during the formation of tomatoes and closely related capsules.We have identified several interesting-looking genes that act differently during the formation of tomatoes and capsules, and are testing them to see how they contribute to tomato formation.
Rachel and Natalia have tested one of the genes so far, and have found that if it doesn’t function properly, the plant produces tomatoes that are large and lumpy, instead of small (we are working with a cherry variety) and smooth.
Even more interesting, the tomatoes have a very strange uneven blotchy coloration.
We noticed immediately that although these tomatoes are still relatively small, they resemble the large and lumpy shapes we often see in cultivated tomato varieties including oddly colored heirloom varieties. We think we may have found a gene that is responsible for some of the dramatic shapes and sizes of the tomatoes we buy at the grocery store and farmer’s market!
Each day had its findings. Each day came with at least one amazing plant that brought all work to a stop. That plant could be one we thought was special because of its rarity (restricted geographic distribution), or one that locals use in some interesting way; sometimes a plant could be deemed special just because it is simply too beautiful. We have selected some of our favorite plants to share them with you.
So what exactly does a botanist do in the field? In the field we look for plants that are in reproductive state, those bearing flowers or/and fruits. Reproductive structures are necessary to differentiate between closely looking species. For each species, we collect flowers, fruits, and leaves; these samples are processed and later dried for future study. The dried and mounted plant samples are called herbarium specimens and they are known to last for hundreds of years.
Las Orquídeas National Park is tucked into the westernmost mountain chain of Colombia, a part of the great Andean Cordillera. In the park the terrain is steep and rough and is crossed by many rivers and streams that originate in the upper part of the mountains. The constant presence of water makes these humid forests a source of abudant epiphytic plants. Epiphytes, like many bromeliads and orchids, are plants that grow on other plants without killing them. Epiphytes root in the humid mixture of mosses and decaying matter that cover the branches of the trees; they are a forest on top of the forest.
The Andes mountain chain, which crosses South America from north to south, is the longest in the world. The Andean forests of the northern range (Tropical Andes hotspot) are home to a level of plant diversity that is without match anywhere else in the world; they are also subject to high rates of deforestation, thus these forests are considered a top priority for conservation. Unfortunately, Andean forests remain insufficiently studied and protected. This lack of baseline information is often times the first impediment to effective conservation: It is impossible to efficiently protect what we do not know or understand.
Clean and fresh travelers. First day, at La Encarnación. Top row: Alirio Montoya, Hector Velásquez, Javier Serna, Arley Duque, María Fernanda González, Camila González, Giovanny Giraldo, Fredy Gómez. Lower row: Felix Escobar, Julio Betancur, Paola Pedraza-Peñalosa.
After 14 days collecting plants in the field, we returned to Bogotá, Colombia’s capital with nearly 700 plant collections, and more than 10,000 photographs. Behind us we left Las Orquídeas National Park‘s 32 thousand hectares of rare and endangered tropical and montane forests, which make it part of one of the most biologically rich ecosystems of the world: the Andean and Chocó forests. We left behind more than 2,000 species of vascular plants, some of them still unknown to the science and probably not found anywhere else.
February 8, 2011; Punta Arenas, Chile; final entry
On the morning of February 6, we arrived in Seno Término, an appropriate name for our last day in the field. The weather mirrored our reluctance to finish such an amazing expedition. The skies were heavily overcast and a constant light rain fell. It seemed reasonable that our last day in the field would be a wet one, like so many before it. Seno Término runs, more or less, east-west, meaning that where we anchored was quite choppy. Across the sound, where there was a less substantial barrier to the wind, sheets of rain flew by one after another.
Despite (or maybe because of) the weather, no one wanted to stay out of the field today. I chose a small band of forest at the base of a granite mountain; at least in the forest the wind is much less. Time zoomed by as I worked back and forth through the forest, reaching and ascending the lower parts of the mountain whenever I could. Even at this late date, with so many sites under our belts, interesting mosses continue to be found. I realized that here, on this last day, I had finally gotten in shape so that climbing a hill didn’t make me out of breath. Talk about a day late and a dollar short!
At lunchtime we moved to our final collecting site, Seno Ocasión, opposite Isla Aguirre, where we had visited earlier. The cold rain persisted, but what was really dampening our spirits was the realization that our expedition was all but over. The ship was tied to a rock wall and we were able to just jump ashore and begin our collecting. The destination-oriented collectors ran ahead in an attempt to reach a nearby rocky peak. Apparently in these exposed areas the wind was fierce and prevented much progress. On the other hand, Kimmy and I hadn’t made it far from the ship when I spotted a steep ravine that ran right down the sea (which the others had run past). It was wet and slippery, but it’s always harder going down than climbing up, so we decided to chance it. At times I had to remove my collecting pack and leave it behind in order to fit onto narrow ledges that I wanted to access. In the end my efforts were rewarded with a moss no one on our ship recognized. Having to crawl backwards to get off the ledge was a small price to pay.
February 5, 2011; unnamed sound northwest of Isla Georgiana, 54°35’S, 71°49’W
As we awoke in Seno Aragay, at the isthmus of the Brecknock Peninsula, a steady, cold rain fell. At least it wasn’t windy.
After a hot breakfast of freshly fried bread, we suited up in our rain gear and headed into the field. Due to the weather we decided three hours in the morning would be about all we could tolerate. Jim and Matt headed in one direction while Blanka and I headed in another. As I came to the summit of a rise I saw Juan and Kimmy being dropped off near the base of a waterfall. As I wandered over the terrain, I desolately picked up the standard mosses just to document their distribution. I got wetter and wetter and colder. On this next to the last day in the field, as we get nearer and nearer to heading home, it was proving hard to get up much enthusiasm as my hand-lens became useless as it was constantly fogged up. When I realized I still had almost two hours left before being picked up, I headed to the base of a dripping cliff.
Upon arriving there, in no time at all I completely forgot about being cold and wet. Instead I was focused on the mosses that grew in sheltered areas under rock overhangs. Here they get less rain (even though, in addition to the rain I was continuously being dripped on from the water running off the cliff) and so i found a completely different suite of species. A couple of these were ones I had not seen before on this trip and I became completely oblivious to my physical discomforts.
I finally saw Blanka on a slope below me and I called to her to come up to where I was. Like me before her, she looked pretty miserable, at least until she got to the cliff base. Instantly her excitement grew as she found liverworts she hadn’t been seeing elsewhere. Quite quickly, Blanka’s promise of only staying there for 10 minutes grew to over 30 minutes. Ultimately, we had to leave to get down to the shore, far below, for our scheduled rendezvous with the zodiac. We were the last to get back to the ship and so the engine room, where we hang wet clothing to dry, was already packed. However, having this space to dry clothing is a godsend; in only a few hours the wettest piece of clothing is dry and warm.
February 4, 2011; unnamed sound directly east of Seno Mama, 54°35’S, 71°34’W
Yesterday was a busy day and I didn’t finish working on my specimens until 10:30 p.m., at which time I just wanted to hit my bunk, not my notebook! The day before yesterday we worked in a beautiful wet forest and we all collected lots of specimens, almost all of which were saturated with water. Not surprisingly, we’re baling in more collections than our drying system can handle, especially with five bryologists in the field. Most collections take about two days to dry on the lowest rack and longer on the upper shelves. At this point we all have wet specimens awaiting dryer space. And it certainly didn’t help that I made almost 100 collections yesterday.
After awhile I am sure that all these places are starting to sound the same to you, especially since you are not here. Quite honestly, at this point, many of our sites are even beginning to merge in my mind. I can distinctly remember the moment when I collected a moss and what the microhabitat looked like, but on which island or in which sound I found it is another story entirely. I assume that this will only get worse in the upcoming days because we are now hitting various sounds that go into the southern shore of Isla Grande (i.e., the large island) of Tierra del Fuego.
Yesterday afternoon we stopped at our final two small islands. We anchored in the canal separating Isla Brecknock from Isla Macías. The last time we divided our group between two islandsJim felt he got the less interesting island and so this time I let him pick first. He and Matt chose Isla Brecknock because it is the larger of the two islands and had a nice waterfall descending near where we were. Blanka, Kimmy, and I took Isla Macías.
