December 13, 2013

In the United States, corn (maize) is a 63 billion dollar per year industry, and it is estimated that each American consumes 25 pounds of corn annually (U.S. EPA). Corn is an important dietary stable across the globe. It is estimated that food consumption will continue to increase for at least the next thirty years (Food and Agriculture Organization of the United Nations), creating a greater need for successful corn harvests. One significant threat to corn production is drought. In 2012, the United States suffered its most severe drought in 25 years, affecting 70-75% of corn production (USDA). Understanding how maize responds to drought stress could help create more resistant plants. Pre-exposure to stress may alter plants’ subsequent responses, implying that plants exercise a form of stress memory (Ding et al. 2012). We demonstrated known stress-response genes including bZIP60 and zmPLC1 were expressed at higher-than-normal levels in drought-stressed B73 maize seedlings. We then demonstrated that plants pre-exposed to drought stress respond differently to the subsequent stress when compared to plants that experienced drought for the first time. Both zmPLC1 and bZIP60 were expressed at higher levels upon the second stress, indicating that maize seedlings may “remember” the previous drought and respond more strongly.

References

Ding Y, Fromm M, Avramova Z (2012) “Multiple Exposures to Drought ‘Train’ Transcriptional Response in Arabidopsis.” Nat Commun. 2012 Mar 13;3:740. doi:10.1038/ncomms1732.

Food and Agriculture Organization of the United Nations. “How to Feed the World in 2050.” Web. United States Department of Agriculture (2012) "USDA ERS - U.S. Drought 2012: Farm and Food Impacts." USDA ERS - U.S. Drought 2012: Farm and Food Impacts. Web.

United States Environmental Protection Agency (2013) “Major Crops Grown in the United States.”

Web. http://www.epa.gov/oecaagct/ag101/cropmajor.html.

Enhydra Lutris, otherwise known as the sea otter, is one of 13 species of otter. It is the only species that can live its entire life in the water making it the smallest true marine mammal. What allows it to do so are two characteristics: the thickest fur of any animal, and a high metabolism. Sea otters are a keystone species and their populations, specifically California sea otters, nearly went extinct in the early 1900's. They have made a comeback to around 2,700 otters, but something is preventing the population from growing more. Sarcosystis neurona and Toxoplasma gondii are two pathogens that have been detected in Enhydra lutris causing peritonitis from protozoal induced encephalitis. This presentation will focus on a study which examined the effects prey choice has on pathogen susceptibility of Enhydra lutris in resources-limited coastal systems. Extensive observation on 118 sea otters and their foraging habits for 5 years revealed relationships between diet specializations and pathogen infection rates. 2 sample t-tests were performed on other variables such as distance to shore, depth, and number of dives in kelp, but none of these showed a relationship with being infected by T. gondii.