Lawrence ChongBIOE 20B Winter 2014Instructor: Dr. Robin DunkinAssignment: Getting to Know Your Food DUE: In Class March 4, 2014

Our relationship with plants is intimatewe eat them everyday! But few us understand how plants go from seed to table and all of the bugs and battles that benefit and sometimes devastate food plants. In the following series of short videos from one of my favorite podcasts Science Friday you will learn more about what goes into producing the food we eat as well as some of the amazing things that these ordinary plants do when not on your dinner plate. Please answer the questions below for each video or podcast. These podcasts are also fair game for the exam.

You can access the podcasts either on the eCommons website or on the Science Friday website:http://www.sciencefriday.com/. The episodes that you need to listen to include:

1) Cultivating the Perfect Pepper, air date 9/22/20112) Battling Blight, air date 5/25/20113) Late Blight Up Close (audio only), air date 9/18/20094) Unwinding the Cucumber Tendril Mystery, air date 08/31/2009

Cultivating the Perfect Pepper:1) What species of pepper does Ed Curry grow? What peppers are members of this species?The species that Ed Curry grows is Capsicum Annuum. Peppers that are members of this species includes bell peppers, jalapenos, and Anaheim crosses.

2) What kinds of traits does Ed Curry select for in his cultivars?The kinds of traits that Ed Curry selects for in his cultivars are mostly skin thickness and flavor.\

3) What is the chemical responsible for giving peppers their spice? Why do different peppers burn differently in your mouth? Where in the pepper is this chemical found?Capsaicinoids are responsible for giving peppers their spice, with capsaicin being one of the most common of the chemical. The location of the burn and its intensity are related to which capsaicinoids are present. In the pepper, this chemical is found as a bead of oil along the placenta wall of the pepper.

4) For which popular food is it critical to have peppers with stable amounts of heat?It is critical to have peppers with stable amounts of heat in salsa. Salsa is one of the most popular foods, being used as a condiment more commonly than even ketchup. Since it is commercially mass produced, its important that it tastes the same every time you buy a bottle of it.

Battling Blight:1) What other organisms is late blight most closely related to?

3Other organisms that light blight is most closely related to are singled celled organisms such as diatoms.

2) What plants are susceptible to late blight? Give a few examples of plants in this family.Plants in the Solanaceae family are susceptible to late blight. A few examples of plants in this family include potatoes, eggplants, and peppers.

3) What are the perfect weather conditions for late blight?The perfect weather conditions for late blight includes unseasonably cold and rainy conditions. Sometimes the market also sells already infected plants.

4) How are the zoospores of late blight spread? What is the scientific name for this plant pathogen?The zoospores of late blight can be spread through water or get dispersed by the wind. The scientific name for this plant pathogen is Phytophthora infestans.

5) How do larger farms protect against late blight? What are the issues that uniquely face smaller organic farmers in dealing with late blight?Larger farms protect against late blight with fungicides, along with possibly copper. Smaller farmers that deal with late blight face the unique issues of being having to be financially viable and stable enough to continue farming, as tomatoes are what could very well be what allows farmers to continue their business as theyre breaking even or losing money on revenue from other crops.

Late Blight Up Close1) What kind of organism is late blight? Why did it used to be classified as a fungus? What other organisms is it most closely related to?Late blight is microbe, fungus-like organism (only since it kills crops) that infected potatoes and tomatoes, as well as other plants. Its been called a fungus back to the days of taxonomy by anatomy, because it looks like a fungus. Other organisms it is most closely related to are diatoms and kelp.

2) What is different about the spores of late blight that distinguish it from a fungus?The spores of late blight have flagellum and they can swim.

3) Why is sequencing the genome of late blight potentially helpful for battling this pathogen?Sequencing the genome provides a deep data set which shows whats going on at the molecular level. In essence its a comprehensive parts list for the organism which will be available to other researchers. The location of different genes is known and how they work can be studied in detail.

4) What is unique about the genome of late blight? What is Dr. Nusbaums theory for how this unique property may bestow pathogenicity (aggressiveness) of the pathogen?The genome is larger and full of transposons, parasitic gene elements that jump around copy themselves. Regions that are full of transposons are basically what attribute to the pathogenic ability and behavior. There are so many transposons that DNA replication starts to make mistakes so that you add or subtract copies of the late blights genes over the generations. The genes become modernized and changes so frequently that the host plants defenses cant keep up with the pathogen.

5) What does Dr. Nusbaum mean by a two speed genome?Dr. Nusbaum refers to the two speed genome as a genome which has many transposons, such as the late blights genome. It has an evolutionary speed advantage since the copied genes change so fast as an effect of having so many transposons which induce more mistakes among attack genes.

6) How does late blight seem to kill the plant?There are sets of genes that the pathogen will secret onto the plant cell. There are signals coded on it such that they will be taken up into the plant cells. The pathogen grows between the cells of the plant and sucks up the juices.

Unwinding the Cucumber Tendril Mystery1) What are some of the types of stimuli that trigger plant movement?Some types of stimuli that trigger plant movement are sunlight and gravity.

2) What famous scientists first described the mystery of the cucumber tendrils?Charles Darwin and Asa Gray first described the mystery of the cucumber tendrils.

3) What is the main purpose of the tendril?The tendril provides an alternative way for the plant to pull itself up to sunlight. It circles around and starts to coil itself around an object once it senses its hit that object.

4) What is strange about the tendrils coil?Whats strange about the coil is that the helix changes directions in the coil.

5) What is the other weird thing that happens when these tendrils uncoil?The other weird thing that happens is that when you pull on them, the coil doesnt unwind but it overwinds and adds more turns to the coil.

6) What did the researchers discover about the internal structure of the coil?The researchers discovered that the tendril changes its internal structure to make the coil. Inside the coil is a flat fiber ribbon. When the tendril grabs onto something, the ribbon shrinks only on one side. The cells on that side contracts and that causes the tendrils to curl.

7) What happens to the cells in the tendril when it curls? What else occurs in the tendril to cause it to have these strange properties?When the tendril curls, the cells on one side contract. The tendril also stiffens up by becoming lignifiedlignin locks the cells in a certain configuration.

8) What is the final closing thought about the differences between the universes that we and plants each inhabit?Plants and animals share the same physical universe, but they have a different temporal universe.