Your salad may hold the secret to evolution

July 23, 2012

David Domozych
Professor David Domozych

Mention a winning trifecta during the summer in Saratoga Springs, and most people think of cashing in at the famed Saratoga Race Course. But Skidmore Biology Professor David Domozych has scored a trifecta of another sort, through research conducted in Skidmore’s Microscopy Imaging Center (SMIC).

For Domozych, SMIC’s director, the research has been instrumental to three recent articles published in top peer-reviewed journals.

He performed immunocytochemical research as part of a team that researched and reported on “The identification of cutin synthase: formation of the plant polyester cutin” which is the cover story of the current issue of Nature Chemical Biology (July 2012, Vol. 8, No. 7).

In addition, Domozych, a cell biologist, is the lead author for a mini-review article in the May 8, 2012, edition of Frontiers in Plant Science titled “The cell walls of green algae: a journey through evolution and diversity.”

He also wrote an invited review titled “The quest for four-dimensional imaging in plant cell biology: it’s just a matter of time,” for a special issue of Annals of Botany on the topic of root biology, published in late May.

It is a rare triple play, particularly for a scientist based at a liberal arts college instead of a major research university. For Domozych, that’s what makes these recent publications gratifying. He’s completed sophisticated research and analysis in Skidmore’s Dana Science Center and shared his work with scholars around the globe. Best of all, he’s been able to introduce undergraduates to advanced technology and encourage them to collaborate with him.

“It is so valuable for students to have a chance to use the kinds of technology available at Skidmore,” said Domozych, explaining that the tools available in the SMIC as well as the Skidmore Analytical Interdisciplinary Laboratory (SAIL) and the College’s GIS lab “are critical for future scientists.”

He added, “Making certain that our students have the tools, knowledge, technology, and training in microscopy is the key to helping them grow as researchers.”

Having access to tools to facilitate his analysis and the ability to share outcomes via the Internet helped Domozych to join with fellow scientists around the world without putting his own research or teaching schedule on hold. This was especially true for the cutin research featured in the Nature article, which was spearheaded by scientists at Cornell University who collaborated with scholars in Denmark, China, and Israel.

The thick, lipid-like cuticle of the tomato taken with a transmission electron microscope
The thick, lipid-like cuticle of the tomato taken with a
transmission electron microscope. The specimen was
chemically fixed and sectioned before imaging.

Their work focuses on the tomato plant and the surface of the tomato itself, which has played a fundamental role in the plant’s ability to adapt. Approximately 450 million years ago as plants emerged from the water to the land, subtle changes in their make up helped them to adapt and grow in a new environment. Tomatoes developed cuticles, a waxy surface that restricts water loss and prevents attacks by pathogens. Essential for growth, durability, and staying power of the plant and its fruit, the cuticle features a key component—cutin. The scientists knew the genetic composition of the cutin polymer but they did not know where and how cutin polymerization took place. To learn more, they zeroed in on mutant tomatoes—those with cutin deficiencies—to determine what happened during their development, and why. “The production of cutin in the developing tomato fruit is profoundly important to its defense against pathogens and resistance to desiccation,” said Domozych.

Noting that tomatoes are “good to eat and simple to play with,” Domozych explained that the plants are one of the most frequently manipulated in science.  As proof, he said, “They came from the tropics and now can be grown in the Arctic Circle.”

A total of 11 scientists collaborated on the research; Domozych’s assignment involved tracing the biosynthesis of the tomato cuticle, in which he used the transmission electron microscope to perform an immunogold analysis. Here, nano-gold particles attached to antibodies were employed to trace the biosynthetic process.

The study shows for the first time that cutin synthesis occurs extra-cellularly and rapidly during the production of the growing tomato fruit. “This process is essential for the development of the fruit," said Domozych. He believes the next step in this research will be to analyze the evolution of different types of tomatoes in the wild to see what has happened to the cuticle over many generations of tomato plants.

Collaboration is often the key to scientific developments, and geographical distance is no longer the barrier that it once was. For his Frontiers in Plant Science mini-review article, Domozych teamed up with scientists in Argentina and Denmark to further examine the cell walls of green algae, which have long been his research specialty.

The researchers called the emergence of green algae onto land “one of the most important events in the history of life” on earth, and explained that today, humans depend on the offshoots of green algae—land plants—for food, textiles, building material, fuel, and pharmaceuticals, among other things. Greater knowledge of the extracellular matrices that cover most green algae—including evolutionary trends in relationship with higher plants—has potential application in the food and pharmaceutical industries, the researchers maintain.

For the Annals of Botany article, on four-dimensional imaging in plant cell biology, Domozych reflects on current technological advances and promotes his belief that 4-DI is the next, best step to analyze plant cell dynamics over time. He notes that modern fluorescence, confocal laser scanning, transmission electron and scanning electron microscopy “provide effective conduits for synthesizing data detailing live cell dynamics and highly resolved snapshots of specific cell structures.” Nevertheless, there are downsides for each of these technologies that limit the opportunity to obtain 4-DI, which he believes is “critical to our understanding of plant cellular genetics and a plant’s response to environmental stress.”
 
This summer, the collaborative research expands as SMIC and Domozych play host to researchers from the University of Copenhagen, the National University of Ireland, Cornell University, and the University of Vermont. Research topics include the elucidation of the evolution of green algae, analysis of root hair growth and investigation of the cell wall of a new model plant, Penium, an alga isolated from a nearby wetland and first cultured at Skidmore.

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