Vitis ripariais a grape species native to North America that grows over a wide geographic area and is subject to a range of environmental stresses. It was one of the rootstocks imported to Europe to help vines there recover from the phylloxera epidemic of the late 19th century. It is a riverbank grape and so is commonly not thought to be drought-tolerant.

“With the global climate change increasing concern about water use, we were interested in looking at what was Vitis riparia’s response to a water deficit, or decreasing water amounts, and what signaling was taking place between the roots and the shoots,” Fennell explained. “It’s been hypothesized by some researchers that a key component of drought response signaling takes place in the root parenchyma cells.”

The SDSU researchers are trying to learn more about the drought signaling mechanism by using a laser capture microscopy unit that allows them to identify and examine specific cells.

“If we fix the tissue correctly, we can capture the cells and capture the information in those cells by extracting RNA, which is the DNA converted to message. We can look at the message, say, between a drought-stressed and a non-stressed plant and identify what’s going on in the drought-stress process,” Fennell said.

Vaughn will then use a whole grape genome microarray — somewhat like a “molecular portrait,” since it monitors differences in the gene expression for many thousands of genes at one time — to determine how cells of the grape plant under stress are responding compared to a plant that isn’t facing drought stress.

The study will generate data that can be compared to other grape genotypes that are more tolerant of water stress.

“It’s valuable for grapes because we’re concerned about sustainability of our crops and water use and the interaction of that roots stock and the top part of the plant that produces the fruit. But it’s also important for providing information for people working on other crops,” Fennell said. “It can give information, say, for somebody that’s working in alfalfa — is this the right tissue to be looking at, what is the signaling that’s going on?”

Vaughn has won a scholarship amount of $4,450, plus tuition and fees, for the work. She is on track to graduate from SDSU in August 2011 with a master’s degree in biological sciences with a specialization in horticulture.